Deciduous Fruit Trees in Southern California - California Rare Fruit ...

Deciduous Fruit Trees
in Southern California
a
Tips for Growing and Selecting

The Right Plant In The Right
MICROCLIMATE
Place
Geographic Location
Elevation
Topography
Exposure

Microclimate and Sun / Heat
• Fruit trees generally
require at least 8 or
more hours of full,
direct sun per day.
• Deciduous fruit trees
can be grown in
locations which receive
less than optimum sun
exposure during the
winter months.
• Many fruit develop
sugar and sweetness in
response to sun and
heat.
• Some fruit and nut
Some fruit and nut
varieties require high
heat to properly mature
the fruit.

• Cold air flows like water
and settles in low
areas. Cold “pockets”
develop in low areas
and behind buildings
and obstacles on
slopes when airflow is
blocked.
• Frost sensitive fruit
trees should be placed
in protected areas or in
areas where cold air
drains away.
• Many deciduous fruit
trees have chilling
requirements that must
be met in order for
proper growth and fruit
production to occur.
Cold and Chill / Frost

Chill Hours
• Chill hours are the number of hours of cold that are required to break down or
degrade the growth inhibiting hormones that cause a deciduous fruit tree to enter
dormancy and that keep a plant dormant, so that normal growth can resume.
• They are most commonly defined as the number of hours that occur during the
dormant season of the plant which fall between the temperatures of 45 degrees and
32 degrees ees Fahrenheit.
e
• If day temperatures following a night of chill raise above 65-70 degrees, then the
hours above those temperatures are subtracted from the accumulated chill hours.
• Deciduous fruit trees often have chilling requirements of 600 or 1000 hours or more
that are needed for proper growth and fruit production.
• This definition iti of chill hours is not always accurate, but this is the most commonly
accepted definition.
• The average # of chill hours varies depending on the year and microclimate. In
San Diego the average # chill hours are:
– Coastal strip (within 10-15 miles of coast) = 50-250 chill hours
– Median areas (between 10 & 25 miles of coast – La Mesa, Clairemont, etc.) = 200-400 chill hours
– Inland areas (El Cajon, Spring Valley, Escondido, Jamul, etc.) = 400-600 chill hours

Tree Selection - Chill Hours
• The variety of the type of fruit is EVERYTHING! Most fruit types have
varieties that require relatively few hours of chill (100 – 400 hours =
low chill varieties).
• If a plant does not receive the required number of chill hours to grow
properly, the growth or performance of the plant will be impaired. The
difference between the number of chill hours required and the number of
chill hours received will determine the severity of the effect.
• If the difference is relatively minor, normal vegetative growth may occur,
however flowering and fruiting will be impaired.
• If the difference is greater, vegetative growth will be sluggish and will
develop at a less vigorous rate than normal. Flowering and fruiting may
be slight or non-existent.
• If the difference is relatively large, the tree will remain dormant much later
than normal. Growth will be sluggish and flowering will not occur. The
tree will enter dormancy earlier in the fall than normal.
• If chill hour requirements are not met for several consecutive years, death
of the tree will probably occur.

Chill Hours
• Having a low chill fruit tree in an area that receives a high number of chill
hours may also cause problems.
• In this case, the tree may receive the necessary number of chill hours to
overcome dormancy very early in the season. If a period of warm weather
occurs, the tree may break dormancy and begin growing. Subsequent
freezing temperatures will often kill this new growth.
• The tree may survive and re-grow when warm weather returns, however
flowering will often not occur during the new growth flush.
• If this pattern occurs more than once during the winter season, the tree
may be killed.
• Selecting fruit tree varieties with chilling requirements appropriate to
your microclimate is an important consideration for successful fruit
tree growing. (Visit the CRFG website at www.crfgsandiego.org)

Tree Size
• The mature size of a fruit tree is usually divided into 3 primary classifications.
Dwarf, Semi-Dwarf, and Standard.
• Size will vary from species to species and to a lesser degree variety to variety.
• Most fruit trees are grafted onto rootstocks, and many times, rootstocks will
influence the mature size of the tree.
• Correct pruning can reduce the mature tree size by roughly 25% or more.

Soil Percolation or “Drainage”
Percolation or drainage is the movement of water vertically into
the soil. A slope does not ensure good drainage.
Soil texture frequently affects the percolation rate.
Sand
– Good aeration and drainage. Does not compact
easily.
– Poor water retention. Nutrient poor, does not hold
nutrients well.
Clay
– Good water retention. Nutrient rich and retains
nutrients well.
– Poor aeration and drainage. Compacts easily.
Silt / Loam
– Best situation. Good water retention, aeration,
drainage, nutrient availability and retention. Does not
compact easily.

Soil Percolation and Drainage
• In order for tree roots to grow and survive, they must have a soil
environment that has the right balance of water and air. Too much or not
enough of either will result in root death.
• To perform a percolation test, dig a hole two to three feet deep and fill it with
water twice. The water in the hole should drain completely away within 12
hours to be considered to have adequate drainage for most trees. If above
average drainage is preferred (as for avocados, papaya, etc.), the water
should drain within 8 hours.
• Soil amendments DO NOT correct soils with poor drainage!
• Organic amendments only affect the soil environment in the area of the soil
that they are mixed. To be beneficial to plant growth, amendments must
be mixed into a large enough area to support a substantial portion of
the root system of the mature plant or plants.
• Organic amendments are only recommended or useful when preparing
an area for planting annuals and small perennials.

Organic Amendments
Mixing organic amendments into planting holes for trees and
shrubs is generally not recommended or beneficial.
• At best, these amendments do no good as the root system on healthy plants
will develop well beyond the amended planting hole.
• At worst, amendments in a planting hole can:
– Restrict or inhibit the development of roots into the non-amended “native” soil.
– Restrict the movement of water into the non-amended soil, forming a perched water table
and causing the soil in the planting hole to become saturated and soggy.
– Will decompose over time, causing the amended soil to compact and the crown of the plant
to settle below surface of the non-amended soil. This settling frequently causes crown rot
and can kill the plant.

Soil Percolation and Drainage
Methods of dealing with soils that have inadequate
drainage include:
1. Plant in raised beds or on mounds.
2. Install a French drain or a chimney drain.
3. Combine a French drain or a chimney drain
with a mound or raised bed.
4. Plant in containers.
5. Find another planting site.

Container Soils
• Potting or container soils are mixtures of
organic and inorganic components
designed to provide optimum water, air
and nutrients for plant root growth.
• Primarily organic soils, container soils
are subject to the same processes of
decomposition and compaction as inground
soils.
• Container soils high in wood and bark
products decompose more quickly than
those with a higher mineral content .
• Container soils should be considered as
temporary and need to be refreshed as
they decompose and compact.
• Always add fresh soil to the bottom of a
root ball and never bury the crown of a
plant by adding more soil to the top of a
potted plant unless the roots of the plant
are exposed.

Container Soils
• Commercially available “cactus soils” are low in organic materials. They
decompose less and they decompose more slowly than soils with a high
wood and bark content.
• An excellent long lasting container soil can be created by mixing ing cactus soil
50-50 with a potting soil that has rice hulls (which decompose much more
slowly than wood and bark products) and organic nutrients, such as
Kellogg’s ‘Patio Plus’.

Soil pH and “Salts”
• When planting into the soil, soil pH and
accumulated salts frequently affect the health
and performance of fruit trees.
• Sensitivity to soil pH and accumulated salts
will vary by fruit type. Avocado and litchi are
most easily damaged by salt.
• Frequently, the soils in Southern California
and the irrigation water we use are both high
in pH and in salt.
• Many fertilizers are also salts and many
manures contain high amounts of salt. Both
can affect the pH and salt level of the soil.

Soil pH
• Soil pH is the acidity or alkalinity of a
soil on a scale of 0-14 with a neutral
pH being 7.0, an acid pH being less
than 7.0, and an alkaline pH being
greater than 7.0.
• When the soil pH is relatively neutral,
all existing plant nutrients are
available to root systems.
• Very acidic and very alkaline soils
tend to tie-up plant nutrients which
result in nutrient deficiency
symptoms in plants.
• Soil pH also directly affects the soil
ecosystem and both the type and the
amount of life found in the soil.
The optimum pH range of
soil varies from plant to
plant but a pH range of 6.3
– 7.3 is generally
considered desirable for
most plants and soil life.

Lowering the pH of Alkaline Soils
• Sulfur - When sulfur is
added to a soil, it combines
with water and forms sulfuric
acid. This easily breaks
down and provides H+ to the
soil which, over time, lowers
the pH.
• Other products which help to make a soil more acidic:
• Oak leaves Bark Coffee grounds
• Pine needles Humus Canadian Peat Moss
• Cotton Seed Meal Compost Ammonium-type fertilizers
• Aluminum Sulfate
Lowering the pH of alkaline soils takes time and
Lowering the pH of alkaline soils takes time and
often relies on the biological activity of organisms
living in the soil!

Salt problems related to plant growth
Most alkaline soils have problems with excessive salt accumulation
due to low rainfall in the area as the salts are not leached from the
soil.
Problems related to high accumulated salts include:
• Reduced seedling germination and survival.
• Faster wilting of plants. It is harder for plant roots to take up water in soils high in
salts and in fact they may even lose water in very salty soils.
• Soils with excessive e sodium can break down soil aggregates and result in a
dispersed, sealed-off soil surface reducing the percolation rate of the soil.
• Salt toxicity to leaves causing dead margins.
• Salty water applied by sprinklers burning foliage.
• Inability of plant to obtain essential nutrients such as phosphorus and iron.

Reclaiming Salty Soils
• Mulches on the surface slow upward evaporation which can aid in reducing the
surface salts. As organic mulches decompose, they form humic acid which helps
to lower the soil pH, therefore making salts more soluble.
• Leaching
• Soil is flooded with water and the salts are leached through the root zone.
This is only practical if water low in salt is available & the soil drainage is
moderate to fast. Unfortunately, most saline soils are clay-like and have poor
drainage.
• For leaching, 12” of water is needed to remove about 70-80% of the salt
in the top 12” of soil.
• Gypsum CaSO 4
– gypsum will slowly replace the sodium in soil and
over time will improve soil structure - the
calcium cations bond together soil particles into
larger aggregates thus improving soil drainage .
– the sodium sulfate is now more easily leached
from the soil.
Gypsum works like this:
CaSO 4 + H 2 O + 2Na + =
Ca ++ + Na 2 SO 4 + H 2 O

Liquid
"Gypsum" and
“Liquid Thrive”
• Liquid "Gypsum" and “Liquid Thrive” contains a high level of soluble calcium
which displaces the sodium. This then creates pore spaces in the soil. The
effectiveness of the calcium is compounded by the use of a polyacrylamide (PAM)
that attaches to the soil particle and remains in the soil for years, helping the soil
structure to resist collapsing. The effect of the PAM is cumulative and long lasting.
• Benefits:
• Improves clay soils by displacing sodium immediately.
• Releases salts, lowering soil EC
• Improves soil drainage
• Reduces crusting and improves infiltration of water and nutrients
• 32 oz. = 200 lbs. dry gypsum

Proper Planting
• Planting hole should 2-3times
as wide and only as deep as
the trees’ root ball.
• Prune any damaged roots, cut
any circling roots and score
sides of the existing root ball.
• Backfill with native soil. Starter
fertilizers, gypsum, or
mycorrhiza can be added at
this time.
• Thoroughly water.
• Apply 2”-3” of organic mulch to
the soil surface, well away
from the tree trunk.
• A word about mycorrhiza.

Mycorrhiza
• Mycorrhiza have formed associations with plant roots for over 400 million years.
• Present in most undisturbed soils, mycorrhiza may be missing from areas where the top
layers of soil have been removed, where soils have been compacted, where fungicides
or excess fertilizers have been applied or in container (soilless) soil mixes.
• Mycorrhiza must come into direct contact with a plant’s root to form a symbiotic association
with the plant!
Benefits of Mycorrhiza:
• Enhanced plant efficiency in absorbing water and
nutrients (especially phosphorous) from the soil.
• Reduces fertility and irrigation requirements.
• Enhances plant health, vigor and drought resistance
and minimizes stress.
• Increased pathogen resistance/protection.
• Enhances seedling growth, rooting of cuttings, and
plant transplant establishment.

Organic Mulches
• Organic material which h falls or is applied to
the surface of the soil and decomposes is all
considered organic mulch.
• There, organisms feed on them and mix the
organic material with the upper soil layers;
these organic compounds become part of the
soil formation process, ultimately shaping the
type of soil formed.
• Mulches gradually incorporate into the soil
profile from the top down. Applying organic
mulches to the entire surface of a soil can
affect the soil in the entire growing
environment. Mulch will decompose and
needs to be reapplied at least annually.
• Mulches can also help to moderate the soil
environment by affecting soil surface
temperature and moisture level.

Mulches
• Mulching a large portion of the feeder root zone is one of
the most beneficial things you can do for your trees.
• Mulch should be at least 2 to 3 inches deep and should not
touch the trunk of the tree or plant. It should extend beyond
the drip line.
• Particle size, texture and degree of decomposition all affect
the physical and chemical properties of organic mulches.
– Coarse materials tend to
• Last longer
• Reduce soil compaction
• Suppress weeds
– Fine materials tend to
• Decompose more quickly
• Have better moisture holding ability as well as
provide more nutrients to the soil as the decompose
• Hold onto nutrients reducing the effects of leaching
• Act as binding agents

Proper Staking
• Stake(s) should be placed away
from the trunk and the tree tied
loosely in two or three opposing
directions if necessary.
• Stakes should only be as tall as
necessary to keep the plant
upright.
• Tree tie material should be at
least 1 inch wide wherever it
contacts the bark.
• Stakes should be removed as
soon as possible.
• Spread or train branches to
develop pproper p tree shape and to
develop strong branch structure.

Proper Planting and Staking
• Only light pruning is
recommended at planting and for
the first year!
• Remove dead or damaged branches,
co-dominant branches and branches
with narrow crotch angles.
• Leave temporary branches that will
be removed later as the tree grows.
• Do Not top the tree! Hormones
Scaffold branches should occur with which stimulate root development
vertical and radial spacing to develop are produced in the apical tips of
strong branch structure. branches. Topping results in poor
branch development and tree
structure.
• Spread or train branches to develop
proper tree shape and to develop
strong branch structure.

Training
• Training branches to grow in specific directions is often a viable option to pruning.
This can take advantage of growth which h has already developed d instead of pruning
off already grown branches and waiting for new branches to grow.
• Using training techniques can avoid the wounds made by pruning and therefore
reduce the problems associated with those wounds.
• Training should be done when branches are young and flexible enough to bend into
shape without breaking or splitting the branch or trunk. Weights, guy wires, stakes or
spreaders can be used to train branches.
• If ties are used, the tie material should be at least 1" wide wherever it comes into
contact with the bark of the tree to prevent damage to the bark.

Watering
fruit
• The trees age and size as well as the soil climate
The trees age and size as well as the soil, climate,
season and other factors affect watering. There are
three key principles to proper watering.

KEY TO PROPER WATERING #1
Water the proper area – the Feeder Root Zone!
Water near the trunk or stem on newly planted plants so that
you wet the original root ball.
Water at the dripline and beyond on plants which are
established in the ground. (The plant may take from a
few weeks to a one year or more to become established
depending on the type and size of the plant, the time of
year that it was planted, soil conditions, cultural practices
and other variables.)
Water further away from the trunk or stem as time progresses
and as the plant grows larger in diameter.

How Plant Roots Grow
• Trees growing in urban areas seldom develop
taproots. t Root systems actually consist of
larger perennial roots and smaller, short-lived,
feeder roots. Large, woody tree roots and their
primary branches increase in size and grow
horizontally.
These roots are usually located in the top 6 to
36 inches of soil.
• The small feeder roots constitute the major
portion of the root system's surface area.
• Feeder roots are located throughout the entire
area under the canopy of a tree. As much as
50 percent of the root system grows beyond
the drip line and may extend as far as two
to three times the height of the tree.
• A Trees feeder roots grow out from large
woody roots and usually grow up toward the
soil surface. At the surface, feeder roots mix
with lawn and shrub roots and compete for the
water, oxygen and minerals that are more
abundant near the surface.
Roots on trees have 3 main
functions:
1. Anchorage
2. Food Storage
3. Absorption of water and
nutrients = Feeder Roots

Depth of Water Extraction by Roots
• Most water is taken up by roots from the top 12” of soil
(40% - 70% or more).
• Up to 90% of the roots that take up water and nutrients
are located in the top 36” of soil.
• Watering methods can determine root depth:
– Light, shallow watering encourages shallow roots.
This results in plants that dry out easily and can blow
over in storms.
– Deep, infrequent watering is best to encourage roots
to penetrate deeply in the soil.
1” of water
penetrates the
ground 1’ in sandy
soil.
It takes 2”-3” of
water to penetrate
the ground 1’in clay
soil.

KEY TO PROPER WATERING #2
Water with sufficient amount of water – enough to
thoroughly wet the entire depth of the Feeder Root Zone.
1” of water penetrates the ground 1’ in sandy soil, it takes 2” of water to
penetrate the ground in clay soil.
90% of feeder roots are found in the top 3’ of soil! (70% are in the top 1’ of
soil.)
Water to an average depth of 1’ to 3’ at each watering for plants that have
been established in the ground. Smaller plants generally have shallower
root systems than larger plants. As a general rule, water to a depth of 6” to
1 foot for plants 1’ or less in height, to a depth of 2 foot for plants 1’ to 4-5
feet in height and to a depth of 3’ for plants larger than 5 feet in height.
For plants in containers, water with enough water to leach excess salts out of
the container and to thoroughly wet the entire root ball at each watering.

KEY TO PROPER WATERING #3
Water at the correct interval – often enough to keep the plant
from wilting, but infrequently enough to allow air to
penetrate the soil.
Roots can drown if the soil is kept constantly wet!
Watering frequency will vary with the time of year, location, size of the plants,
soil, weather conditions and many other variables.
On average:
Water new plants in the ground 1-2 times per week.
Water older established plants in the ground 1 time per week to 1 time per
month depending on the variables.
Water plants in containers 1-3 times per week.
There are very few exceptions where plants should be watered every
day! Watering too frequently will exclude oxygen from the soil and
cause roots to drown as well as promote diseases!

Fertilizers
• There are 17 elements that plants need in order to successfully grow and complete
their life cycle. These elements are called the “Essential Elements” . 14 of the
elements are minerals taken in by roots from the soil.
• These essential elements are broken down into two categories: macro elements and
micro elements.
• Macro elements are also know as major elements. The macro elements that are
minerals taken in by roots from the soil are nitrogen, phosphorus, potassium,
calcium*, magnesium*, and sulfur* These elements are needed in larger quantities
by the plant than the micro elements. (* elements are sometimes referred to as
secondary elements.)
• Micro elements are also know as trace or minor elements. The micro elements are
Boron, Zinc, Manganese, Chlorine, Iron, Molybdenum, and Copper and Nickel.
These elements are needed by the plant in smaller amounts than the macro
elements.
• The availability of these nutrients for plants to absorb from the soil are affected
by the soil pH and the microorganisms which live in the soil.

Fertilizer
Types
– Liquids: Generally fast acting but quickly lost from the soil
due to leaching. Must be applied more frequently than
other forms of fertilizer. Easily applied to a large portion of
the feeder root zone. Useful as a foliar fertilizer, commonly
used to correct micronutrient deficiencies .
– Stakes or spikes and tablets: Concentrate the fertilizer in
small areas. Only the roots near these locations have
nutrients available, resulting in a very small portion of the
feeder roots utilizing the fertilizer application. Must be
placed in the feeder root zone and must be placed in many
locations to maximize benefit. Most useful when used in
containers.
– Granules, meals, and manures: Easily applied to a large
portion of the feeder root zone. Frequently longer lasting
but slower acting than liquid fertilizers. May be subject to
being “washed away” if applied to slopes. User may have
a greater risk of over applying and “burning” their plants.
Apply fertilizer evenly
on mulched and
unmulched surfaces
out to about 1½
times the crown
radius.

Fertilizers
• Fast-release or water-soluble fertilizers are less
expensive than slow-release products, which release
nitrogen over an extended period; however, the
nutrients in a fast-release fertilizer may leach quickly
through the soil.
• Slow- or controlled-release fertilizers have extended
release periods compared to fast-release fertilizers
whose nitrogen is water-soluble and readily available
to the plants.
• Organic fertilizers– Most rely on soil organisms to
convert them to nutrients which are available for
absorption by plant roots. Often temperature
dependant and slow release. Many provide food for
soil organisms and help to improve the soil structure
and the soil ecosystem.
• Conventional ie. Synthetic fertilizers – More
formulations and types available. Not temperature
dependant. Provide nutrients but does not improve
soil health.

The Effect of Micro-organisms
on Nutrient Absorption by Plants
• Soil micro-organisms can directly affect nutrient absorption by plants. The
nutrients that are most affected include Nitrogen and Phosphorous.
• Sulfur (S) is usually found in low levels in soils and it is frequently obtained
by decomposing organic matter.
• The application of mulches, soil amendments or fertilizers that are high
in salts, release high levels of nutrients too quickly, modify soil pH
outside a desirable pH range, or cause soils to become too soggy,
excluding adequate aeration, can kill soil micro-organisms!
• Organic fertilizers and manures frequently provide food to the organisms
which live in the soil as well as provide necessary plant nutrients.
Byproducts of decomposition of these organic fertilizers and manures may
also be beneficial (such as humic acid).

Nitrogen - the nitrogen cycle.
• Nitrogen is both added to the soil environment and lost from the soil
environment by natural processes. This is known as the Nitrogen Cycle.
Nitrification
cato
• Nitrogen Fixation is the change of atmospheric nitrogen (N 2 gas) into NH 4 + by
bacteria and some algae. This NH 4 + is now or will soon be available to plant
roots.
• The decomposition of organic matter releases NH4+ into the soil for
absorption by plant roots. The amount of NH4+ depends on the origin of the
organic matter.

The Nitrogen Cycle - N Loss
– Denitrification
ifi ti
• Nitrate (NO 3 -) can be changed to N 2 gas by certain bacteria in the soil. This
occurs when soils are saturated and the bacteria are in need of oxygen.
• The bacteria take the oxygen from the nitrate and release it as N 2 gas. This gas
bubbles to the surface and the nitrogen is lost.
• Tends to be worse in soils high in manures and in soils with poor drainage.
- Immobilization
• Bacteria, fungi, and algae take up ammonium and nitrates from the soil for their
own growth and therefore make it unavailable for plants.
• This tends to occur when large amounts of organic matter are introduced to the
soil and is worse when the organic matter has a high C/N ratio.
• All of the nitrogen will be released to the soil upon the death of the
microorganisms.

Nitrogen (N)
• The most critical element in plant growth. This is the nutrient that is most
commonly lacking in soils and most frequently needs to be added to soils.
• Can be absorbed into roots in only two forms: NH 4 + (ammonium) & NO 3 - (nitrate).
The nitrate form of nitrogen is very prone to leaching.
• Sands and well drained soils tend to lose NO3- very easily during high rainfall or
frequent irrigation.
• Fertilizing with the ammonium form of nitrogen (NH4+) is less prone to leaching as
the + charge tends to bond with the negatively charged clay particles.
• Ammonium Volatilization occurs when ammonium fertilizers are applied to the
surface of alkaline soils. These soils, typically high in calcium and carbonate, can
react with the ammonium fertilizer and result in losses of up to 30% to the
atmosphere. Ammonium fertilizers should be incorporated into the soil to
lessen this loss or covered with mulches when applied to the soil surface.
• The addition of some form of nitrogen type fertilizer (organic or
inorganic) is most often needed to maintain plant health on most
types of plants!

Nitrogen Deficiency Symptoms
• Light green to yellow color on leaves. Older leaves show symptoms first
• Leaves may go completely yellow but still be alive. Yellowing occurs from the tip of
the leaf downward and may later dry up.
• Plants are spindly and stunted

Phosphorus (P)
• The second most needed d plant nutrient. t It is the least mobile in soil
and minimally affected by the leaching processes.
• Most plants get phosphorus by organic matter breakdown near
the roots.
• Even though phosphorus may be present in the soil, it can be easily
tied up by iron, aluminum, and calcium depending on the pH of the
soil.
• Mycorrhiza which have formed associations with plant roots can
greatly increase the ability of the plant to absorb phosphorous.
• Addition of phosphorus fertilizer is often necessary due to the
high need of plants and the ease of phosphorus tie-up. It is best
when it is worked lightly into the soil or when covered by an organic
mulch.

The Phosphorous Cycle

Phosphorus Deficiency Symptoms
• Leaves can show a dark green or purple color.
• Yellowing of the leaves later occurs and leaf drop follows
• Flowering is poor or non-existent.

Soil Nutrients
The Physical or Chemical Properties of Soil can also affect
the availability of certain soil nutrients. These include:
• Potassium (K) is usually very present tin soils in the mineral lform of
feldspar but is very insoluble resulting in a very small amount
available to plants. Therefore, fertilizers are often needed.
• Calcium (Ca) is very seldom deficient, except in very sandy soils.
Calcium is very soluble and wet, rapidly draining soils may leach
out calcium.
• Iron (Fe) is generally found in most soils but can be tied up on
alkaline soils.
• Manganese (Mn) is usually readily available to plants except in
highly alkaline soils. Can be a toxic element in highly acidic soils.
• Zinc (Zn) is tied up in highly alkaline soils and can also be leached in
sandy soils.

Potassium (K)
• Usually very present in soils in the mineral form of feldspar (KAlSi 3 O 8 )b but tis very
insoluble resulting in a very small amount available to plants. Therefore, fertilizers
are sometimes needed.
• Uses in the plant:
– helps iron move throughout the plant
– aids in fighting plant diseases
– strengthens cell walls
– aids in frost protection
Deficiency Symptoms
• Yellowing occurs mainly on the margin of the leaves and does not extent inward until
severe symptoms show
• Leaf edges turn brown and leaf edges dry up and curl under

Magnesium
• Rarely deficient in plants. Often naturally found in soils in the mineral dolomitic
limestone CaMg(CO 2 ) 2.
• Aids in the uptake of phosphorus.
Magnesium Deficiencies
• Bottom leaves are affected first but new leaves soon follow.
• Old leaves show interveinal chlorosis
• Puckering of the leaf surface is sometimes seen along with rapid leaf drop.

Iron (Fe)
• Generally found in most soils but can be tied up on alkaline soils.
• Symptoms show on young leaves first.
Iron Deficiencies
• Leaf show yellowing between the veins with the veins staying green (call iron
chlorosis).
• In severe cases, leaves turn whitish and then can blacken.
• Eventually, shoot tips may die.

Zinc (Zn)
• Tied up in highly alkaline soils and can also be leached in sandy soils.
• Mottled yellow spots occur
Zinc Deficiencies
• Small leaves es form, rosetting at tips of plants, short internodes

Fertilizers
• Over fertilizing can be detrimental to the
health of your plants, can increase pest
problems, can result in pollution to the
environment and can adversely affect the
health of the soil ecosystem.
• Use a soil analysis, leaf analysis, or look
for nutrient deficiency symptoms to
adequately determine plant nutrient
requirements.
• Timing fertilizer applications to season
growth and applying the proper nutrient
ratios can maximize the health and
performance of your fruit trees.

Timing Fertilizers to Seasonal Growth
Apply a
balanced
fertilizer to
promote
growth, and
fruit
production.
Apply low nitrogen-higher
phosphorous fertilizer in mid
fall to promote root growth,
flowering and fruit production
in Spring.
Apply a mild
nitrogen fertilizer
to promote a last
flush of growth
after the heat of
Summer is over.

Pest Control - Ants
• Ants “farm” many honeydew producing insects.
Controlling ants and keeping them out of your
trees can greatly help to reduce insect pest
problems.
• Ants can be kept out of trees by banding tree
trunks with sticky substances such as Tanglefoot.
• Trim branches to keep them from touching
structures or plants so that ants are forced to
climb up the trunk to reach the foliage.
• Protect young or sensitive trees from possible
injury by wrapping the trunk with a collar of heavy
paper, duct tape, or fabric tree wrap and coating
this with the sticky material.
• Check the sticky material every few days and stir
it with a stick to prevent the material from getting g
clogged with debris and dead ants, which will
allow ants to cross.

Ants
• When properly p used, baits are more effective and safer than sprays or
granules to control ants.
• Bait products must be slow-acting so that the foraging ants have time
to make their way back to the nest and feed other members of the
colony before they are killed.
• Ant baits contain either carbohydrates (e.g., sugars), proteins, or oils,
or some combination of these as attractants along with an active
ingredient (toxicant).
• Different attractants are more effective against different species of ants
and at different times of the year.
• In the case of Argentine ants, sweet baits are attractive year-round.
• Protein baits are attractive ti primarily il in the spring because they are
brought back to the colony to feed the developing brood.
• Offering a small quantity of each kind of bait and observing which
one the ants prefer is a good way to determine what to use.
• Control with baits may take several weeks or more to be
complete.

Pest Control
• Tolerance to low levels of plant pests is a key ingredient to successful pest
control.
• When pest numbers become large and damage to your plants becomes
unacceptable, control measures often become necessary.
• Proper timing is essential for control measures to be successful!
• Most soft bodied insects can be
controlled by using insecticidal
soaps.
• Soaps also help to clean your
trees and remove honeydew,
sooty mold, and dirt and dust.

• Many sucking insects
produce large
quantities of a sticky
excrement known as
honeydew, which often
turns black with the
growth of a sooty mold
fungus.
Sooty Mold
• Sooty mold blocks
sunlight and reduces
photosynthesis.

Pest Control
• Most pest control products used on fruit trees are
contact killers. They kill what they touch.
• The key to successfully using pest control products
are to be complete and thorough with your
applications and to be consistent with your follow up
applications!

Aphids
• Aphids affect nearly all fruit trees. They occur primarily on young foliage and shoot
tips.
• Large populations of aphids cause curling, yellowing, and distortion of leaves and
stunting of shoots. This may affect growth to the point of hampering the
development of fruiting wood and tree development.
Damage caused by Green Peach Aphids
• Aphids (as well as other “sucking” insects like soft scale and whitefly) can
produce large quantities of a sticky excrement known as honeydew.

Aphids
• Aphids have many generations a year. When the weather is warm, many
species of aphids can develop from newborn nymph to reproducing adult
in 7 to 8 days. Because each adult aphid can produce up to 80 offspring
in a matter of a week, aphid populations can increase with great speed.
• High levels of nitrogen fertilizer favor aphid reproduction.

Aphids
• A few aphid species attack parts of
plants other than leaves and shoots.
• The woolly apple aphid infests woody
parts of apple roots and limbs, often
near pruning wounds, and can cause
overall tree decline if roots are infested
for several years.

Pear Sawfly (Pear Slug)
• Host specific. Plants commonly
attacked: Pears, plums, cherry.
• Larvae feed on leaves causing a
“windowing” effect.
• Damage may cause reduced vigor
g y g
from loss of leaves.

Green Fig Beetle
• Plants commonly
attacked: Fig, soft
fruit.

Green Fig Beetles
• Large grubs (larvae) are
frequently found in
compost piles and in
soil that is rich in
organic material.
• Traps hung in trees
during the summer can
help reduce Fig Beetle
populations and can
help to reduce damage
to the crop.

Codling Moth
• The larvae of the codling moth (Cydia pomonella) )is
the common apple worm. It attacks apples, pears,
quince, walnuts, and other tree fruits.
• Codling moth adults are about 1/2 to 3/4 inch long
with mottled gray wings that are held tentlike over
their bodies. Their appearance blends well with most
tree bark, making them difficult to detect.
• Codling moths can be distinguished from other moths
by the dark, coppery brown band at the tip of their
wings.
• Codling moths overwinter as full-grown larvae within
thick, silken cocoons under loose scales of bark and
in soil or debris around the base of the tree.
• The larvae pupate inside their cocoons in early spring
and emerge as adult moths mid-March to early April.
• After mating each female deposits 30 to 70 tiny, discshaped
eggs singly on fruit, nuts, leaves, or spurs.
After the eggs hatch, young larvae seek out and bore
into fruit or developing nuts.

Codling Moth
• After completing development they leave the fruit and drop from the trees
to search out pupation sites and continue the life cycle in the soil or on
debris under the tree; some crawl back up the tree to pupate in bark
crevices.
• The rate of development will vary with temperature, proceeding more
rapidly in warmer weather and climates.
• Depending on the climate, codling moth can have two, three, and
sometimes four, generations per year.
• Trapping the adults can help to control this pest. Traps can also help time
pesticide applications. BT and spinosid are somewhat effective if applied
before the larvae chews into the fruit.

Oriental Fruit Moth
• The Oriental fruit moth (OFM), native to China, was
introduced to the United States from Japan about
1913 on infested nursery stock.
• The OFM is now found in all regions of North
America where peaches are grown.
• Although it is most important as a pest of peach, the
OFM has an extensive host range that includes
apple, quince, pear, plum, cherry, apricot, nectarine,
and some rosaceous ornamentals.
• The moths overwinter as full-grown larvae in
cocoons in tree bark crevices, weed stems and trash
on the ground. In the spring, the larvae change into
pupae. The adults begin to emerge about the time
peach blossom buds show pink.
• It may have five to six generations per year.
• The larva attacks the twigs and fruits of most host
plants.

Oriental Fruit Moth
• When the terminal parts of rapidly growing twigs are succulent, they are frequently
attacked by the Oriental fruit moth. Succulent peach twigs are exceedingly attractive
to the larvae. Plum, apple and cherry may occasionally be moderately infested. One
larva may enter two to five twigs or even more. Young trees are usually more heavily
attacked than old bearing trees.
• One larva may enter two to five twigs or even more. A full-grown larva will emerge
from a twig and seek a place to spin a cocoon.
• In peach fruit, two distinct types of injury are visible. One is caused by feeding on or
entrance into the side of the fruit early in the season when the fruit is small.
Frequently called "old injury," this is usually caused by larvae that have abandoned
the twigs and gone to the fruit. Injury caused by entrance at the stem, sometimes
called "new injury," occurs when the fruit is almost full grown. This injury is caused by
newly hatched larvae that go directly to the fruit.
• When a larva has completed its development in a peach it tunnels to the surface and
• When a larva has completed its development in a peach, it tunnels to the surface and
leaves the fruit through a clean hole.

Shothole Borer
• The shothole borer is a serious pest of many deciduous
fruit and nut trees, including stone fruits, apples, pears,
and almonds.
• Adult borers are tiny bullet-shaped, reddish black
beetles about 0.10-inch long.
• Female shothole borers bore small holes, which look
like shot holes, in the bark and lay eggs in a gallery 1 to
2 inches long running lengthwise down the cambium
layer of the tree.
• Hatching larvae feed and excavate secondary galleries
at right angles to the egg gallery, creating a gallery
system that looks like a centipede.
• Larvae spend the winter in their galleries beneath the
bark.
• Two or three generations occur a year in California.

• Shothole borers can and do kill
trees. Once a tree has been
seriously attacked, there is often
no way to save the tree.
• Systemic insecticides such as
imidacloprid can be beneficial if
used before extensive damage
occurs.
• Borers often attack stressed trees.
Keeping your fruit trees healthy is
the best way to prevent this pest.
• Healthy, vigorous trees can often
defend themselves from minor
borer attack.
• Dormant sprays do not control
borers.
Shothole Borer

Peach Twig Borer
• Larvae bore into the growing g shoots of twigs and
ripening fruit or nuts. Shoots and leaves wilt and die
back one to several inches from the growing tips of
twigs. In fleshy fruit, injury is usually superficial.
• Spraying during the growing season is difficult to time
pesticide applications effectively. Sprays must be
applied to control hatching larvae before they enter
twigs or fruit.
• In the fall, winter, and very early spring, peach twig
borers overwinter in limb crotches in cells called
hibernacula covered with chimneylike piles of frass
and sawdust.
• Larvae emerge in early spring and migrate up twigs
and branches, where they attack newly emerged
leaves and shoots. Pupation takes place in protected
t places on trees and occasionally in the stem cavity of
infested fruit.
Ad lt l ti i di id ll t i d f it i
• Adults lay tiny eggs individually on twigs and fruit in
the spring and summer and on young branches in the
fall.

Root Knot Nematodes
• Root knot nematodes attack a wide range of fruit
trees.
• Root knot nematodes are difficult to control and can
be spread easily from garden to garden in soil (for
example, on tools, boots, etc.) and plant parts.
• Root knot nematodes survive from season to season
primarily as an egg in the soil. After the eggs hatch,
the second stage juveniles invade roots, usually at
root tips, causing some of the root cells to enlarge
where the nematodes feed and develop.
• Root knot nematodes usually cause distinctive
swellings, called galls, on the roots of affected
plants. The nematodes feed and develop within the
galls, which may grow to as large as 1-inch in
diameter on some plants but are usually much
smaller.
• The water- and nutrient-conducting abilities of the
roots are damaged by the formation of the galls.

Root Knot Nematodes
• Above ground symptoms of a root knot nematode infestation include wilting, loss
of vigor, yellowing, and other symptoms similar to a lack of water or nutrients.
• Fewer and smaller leaves and fruits are produced, and plants heavily infested
early in the season may die.
• Damage is most serious in warm, irrigated, sandy soils.
• Some control may be achieved by using fruit tree rootstocks that are resistant
to nematode injury, increasing the organic material in the soil with the use of
mulches or soil amendments, or by introducing beneficial Steinernema feltiae
(Sf) nematodes.

Snails and Slugs
• Snails may lay eggs up to six times a year. It takes about 2 years for snails to
mature.
• Snails are excellent climbers and often will also feed on foliage and fruit of some
trees; citrus are especially susceptible to damage.
• The brown garden snail (Helix aspersa) is the most common snail causing problems
in California gardens; it was introduced from France during the 1850s for use as
food.
• The white garden snail, Theba pisana (Mueller), is the worst potential agricultural
pest of the helicid snails introduced to North America
• The snails were found and identified in August 1985 in San Diego, California, at
several localities in about a 10 square mile area

Snail and Slugs
• Most snail and slug baits have • Baits containing Iron Phosphate kill
mateldehyde as the main
snails and slugs but are of very low
active ingredient.
risk to dogs, cats, wildlife and
people. They are also less toxic to
fish than conventional snail baits.
• Mateldehyde is very toxic to
mollusks as well as dogs, cats,
wildlife, fish and people.
• As these baits break down they
become plant nutrients in the form of
iron and phosphorous.

Snail and Slug Control
• Snails and slugs cannot crawl over copper.

Birds
• Many birds eat insects in the garden, however, some also eat ripening fruit.
• Birds should be discouraged from you fruit, but never harmed or killed.
There are several products available to protect your crop from birds.
Scare Tape

Birds
• The most effective bird deterrents are nets. Any size net which
completely l encloses the tree will be effective against birds.
•1/4" mesh bird net from Bird-B-Gone is a solution for both birds and Fig Beetles.

Pests and Diseases
Pocket Gophers
• Fruit tree roots are a favorite food of
gophers, who can easily kill a large plant.
One passive method of control is to plant
the tree in a large aviary wire basket.
• The wire should have openings no larger
The wire should have openings no larger
than ½” and the top edge of the basket
should extend at least 2”-3” above the
surface of the soil.

Gopher Control Products
Traps, Baits and Gases
• Important in the effectiveness of these products is
that they should be placed in a fresh tunnel or run.
• Traps are often the most effective. Use in pairs and
placed back to back.
• Baits work well if used properly. A bait injector tool
is a useful tool.
• Gases are most effective when the soil is moist.
Gases are often the least effective of these options.

Peach Leaf Curl
• Fruiting plants affected by Peach Leaf Curl are limited
to Nectarine and Peach.
• Symptom appear on leaves in spring. Likes cool, wet
weather below 80 degrees. Leaves fall off as temp get
hot.
• May damage twigs & shoots causing them to die.

Peach Leaf Curl
Taphrina deformans
• Peach leaf curl affects the blossoms, fruit, leaves, and shoots of peaches and nectarines, and is
one of the most common disease problems for backyard gardeners.
• When severe, the disease can reduce fruit production substantially.
• Leaf curl first appears in spring as reddish areas on developing leaves. These areas become
thickened and puckered, causing leaves to curl and severely distort. The thickened areas turn
yellowish gray and velvety as spores are produced on the surface by the leaf curl fungus.
• Affected leaves later turn yellow or brown and can remain on the tree or may fall off; they are
replaced by a second set of leaves that develop more normally unless wet weather continues.
• The loss of leaves and the production of a second set result in decreased tree growth and fruit
production. In addition, defoliation in spring may expose branches to sunburn injury.
• The leaf curl pathogen also infects twigs and shoots. Affected shoots become thickened,
stunted, distorted, and often die.
• Only rarely do reddish, wrinkled areas develop on fruit surfaces; later in the season these
infected areas become corky and tend to crack. If leaf curl infection builds up and is left
uncontrolled for several years, the tree may decline and need to be removed.
• It takes about 2 weeks after leaves emerge from buds before leaf symptoms appear.

Peach Leaf Curl
Taphrina deformans
• The fungus survives the hot, dry summer on the tree’s surfaces.. In spring, the
fungus is moved by splashing water and can infect newly developed leaves.
• To prevent peach leaf curl, treat peach and nectarine trees every year after leaves
have fallen. Copper-based fungicides, calcium polysulfide, or synthetic fungicides
can be used.
• To be effective, copper-containingcontaining compounds must have at least 50% copper.
• It is be advisable to apply a second treatment in spring, preferably before buds
begin to swell, but definitely before bud break (when green color is first visible).
• Although symptoms of leaf curl are seen primarily in spring as new leaves develop,
there is little you can do to control the disease at this time. Normally, diseased
leaves fall off within a few weeks and are replaced by new healthy leaves unless it
is rainy.
• Development of leaf curl ceases when young tissue is no longer developing or
when weather turns dry and warm (80° to 85°F).
• If leaf curl symptoms occurred on your trees in spring, be sure to treat the
following fall, around mid December, to prevent more serious losses the next
year.

Coryneum Blight (Shot-Hole Fungus)
• Fruiting plants affected by Coryneum Blight : Almond, Apricot, Cherry, Nectarine,
Peach, Plum.
• Affects leaves, fruits, buds, blossoms & twigs. May kill buds, cause blossom blight,
shot-hole symptoms in leaves, cause twig cankers that may kill a branch.
• Gumming is common around infected buds & cankers.
• Spots on fruit become hard & rough with dry corky areas underneath.

Coryneum Blight (Shot-Hole Fungus)
• Reddish or purplish brown spots about 0.10 inch in diameter
occur on new leaves and shoots. The spots expand and their
centers turn brown.
• Tiny, dark specks sometimes form in the center of lesions,
especially on leaves. Spots on young leaves have a narrow,
light green or yellow margin and their centers often fall out as
leaves expand, leaving "shot holes."
• Buds of peach, nectarine, and sometimes apricot are killed in
the winter. Fruit may become rough and corky. Spotting
occurs on the upper surface. Concentric lesions may develop
on branches.
• The fungus that causes shot hole survives the dormant
season inside infected buds and in twig lesions. The spores
produced on lesions can remain alive for several months.
They are spread by splashing rain or irrigation water.
• Spores that land on twigs, buds, blossoms, or young leaves
require 24 hours of continuous wetness to cause infection.
Only the current season'ss growth is susceptible to infection.

Brown Rot
• Fruiting plants affected by Brown Rot include stone fruit (Apricot, Cherry,
Nectarine, Peach, & Plum) and Citrus.
• Infection consumes entire fruit as fruit ripens.
• Likes high humidity & warm temp. 55-75
75.
• Citrus infection start as soft leathery areas and develops an odor.
• Skirt lower branches to aid in preventing spread from spores in ground

Brown Rot
Pathogens: mostly Monilinia fructicola and M. laxa
• Ripe fruit rot caused by Monilinia results in firm, circular spots that spread rapidly
over fruit. Monilinia causes dark brown lesions on fruit that eventually turn black from
the development of pseudosclerotia (fungal tissue),
• Fruit with brown rot infections are shriveled and develop powdery tan masses of
spores. Individual fruit may be infected, but rotted fruit usually occur in clusters that
are stuck together.
• Injured fruit and fruit that touch each other are the most susceptible to brown rot
infections.
• When Monilinia-diseased fruit remain on the tree, they are known as mummies.
• Removing or turning under thinned fruit helps reduce fruit brown rot. Thinned fruit
can be a source of inoculum for brown rot on ripening fruit, especially if they are left
where they will come in contact with irrigation water.
• Fungicides are preventive, not eradicative; they must be applied to uninjured
fruit before infections occur. Injured fruit cannot be protected from rot caused
by Monilinia

Dormant Spraying
• Dormant Spraying helps to control over wintering insects on fruit trees and diseases
such as peach leaf curl, shot hole fungus and brown rot on stone fruit.
• Sprays should be applied between December and February when the trees are most
dormant.
• For the best control, spray two to three times approximately two weeks apart.
• Avoid applying dormant sprays if rain is expected within 48 hours of spraying.
• The most effective spray for controlling diseases is just before bud break as the buds
are swelling but before they have opened.
• If bud break has occurred and the buds are open and showing color, it is too late to
dormant spray.
• Two products are usually combined and applied as a dormant spray treatment.
One to control over wintering insects and the other to control dormant
diseases.

Dormant Spraying
• Oil sprays are used to suffocate over wintering
insects.
• Dormant sprays do not control boring insects
such as shot hole borer and peach tree borer!

Dormant Spraying
• Fungicides id are used to control dormant diseases.
• Fungicides containing lime sulfur (calcium polysulfide) are very effective.
• Lime sulfur smells like rotten eggs and can stain concrete and stucco.
• Do not apply lime sulfur sprays to apricots or apricot hybrids!
• Copper based sprays or fungicides using synthetic chemicals are also available for
dormant disease control.
• Copper fungicides should contain 50% copper to be most effective.

Apricot Eutypa Dieback
Pathogen: Eutypa lata
• Fruiting plants affected by Eutypa Dieback:
Apricot.
• Causes limbs or twigs to wilt & die suddenly in
late spring or summer with the leaves still
attached. Bark has amber gumming.

Apricot Eutypa Dieback
Pathogen: Eutypa lata
• Eutypa dieback, also known as Cytosporina, gummosis, and limb dieback,
causes limbs or twigs to wilt and die suddenly in late spring or summer with
the leaves still attached. The bark has a dark discoloration with ambercolored
gumming; infected areas in the interior of the wood are discolored
brown.
• This fungus infects fresh pruning wounds when rainfall occurs 2 to 6 weeks
after pruning. While infections can occur at any time of the year during rainy
periods, the greatest incidence is in fall and winter.
• Remove infected limbs at least 1 foot below any sign of the disease. The
preferred control method is to prune during July and August after harvest.
• Ideally, pruning should be completed at least 6 weeks before the first rains. If
pruning wounds are made outside of the preferred pruning period of
July/August, use a fungicide to treat the wounds.
• Pruning during the summer months may encourage bark boring
insects.

Powdery Mildew
• Fruiting plants affected by
Powdery Mildew include: Apple,
Quince, Stone Fruit, Grape,
Caneberries, Strawberry,
Mango, Papaya.
• Different powdery mildew fungi
cause similar symptoms.
• Does not require moist
conditions to establish & grow.
Like swarm temp.
• Attacks new growth, buds,
shoots, flowers, leaves & fruit.

Powdery Mildew
• The disease attacks new growth including buds, shoots, and flowers as well
as leaves. New growth is dwarfed, distorted, and covered with a white,
powdery growth.
• On apple, grape, apricot, nectarine, and peach, young fruits develop weblike
russetted scars and sometimes develop a rough corky skin.
• Grapes with a severe infection may also crack or split and fail to grow and
expand.
• Powdery mildew spores are carried by wind to new hosts. Moderate
temperatures and shady conditions are generally the most favorable for
powdery mildew development. Spores and mycelium are sensitive to
extreme heat and direct sunlight.
• The best method of control is prevention. Avoiding the most susceptible
varieties and following good cultural practices will adequately control
powdery mildew in many situations. However, where conditions are
favorable, susceptible fruit trees and berries may require protection ti with
fungicide sprays.

Rust
• Fruiting gplants affected
by Rust: Nectarine,
Peach, Caneberries.
• Cankers appear as
blisters or small splits in
bark.
• Leaf lesions occur
spring, summer & fall.
May cause defoliation.
• Lesions may occur on
fruit.
• The fungus survives in twig cankers or on other host parts.
• Airborne spores depend on wetness for infection.
• Infections of young twigs and leaves are the most common symptoms, but in
California, fruit infections may be a major component of the disease as well.

Rust
• Fruit symptoms may resemble damage caused by stink bugs; confirm rust by the
presence of rust spores within the fruit lesion or by leaf or twig symptoms.
• Twig cankers are the first symptoms of the disease in spring. Cankers develop after
petal fall on 1-year-old fruiting wood. They appear as blisters and longitudinal splits in
the bark about 0.12 to 0.25 inches long.
• Leaf lesions usually develop after cankers form in spring and may continue to
develop through summer and into fall. The lesions appear as bright yellow, angular
spots on the upper surface of leaves. The lower surface of the leaves contains brown
spore masses.
• A high incidence of early leaf infections may cause midseason defoliation and
numerous fruit infections at harvest. Early and severe defoliation also may reduce
yields and stimulate the production of new leaves and buds late in the growing
season.
• Fruit lesions may develop during the growing season after leaf symptoms. They first
develop as small, brownish spots (0.1 inch) with green halos on mature, yellow fruit.
When fruit reddens, lesion halos become greenish yellow. The lesions are sunken
and extend several millimeters into the fruit.
• In orchards where rust develops it is managed with a fungicide treatment in spring.

Scab • Fruiting plants affected by
Scab include: Apple,
Peach, Pear.
• Favors coastal areas where
spring & summers are cool
& moist.
• Apple leaves puckered,
black circular spots on
upper surface, velvety
spots on lower.
• Scabby areas on fruit occur
when fruit ½ grown & start
near stem. Fruit may be
stunted, misshapen or
crack.
• Cankers occur on stems of
peach.

Scab
Pathogen: Venturia spp.
• Scab is most severe in coastal areas where spring and early summer weather is cool
and moist. Infection occurs most rapidly between 55° and 75°F and leaves or fruit
must remain wet continuously for a minimum of 9 hours for infection to occur.
• Scab first appears as velvety, dark olive-to-black spots on fruit, leaves, and stems.
On leaves, infections cause leaf puckering and twisting and eventually tear with age.
Defoliation follows severe early leaf infection.
• When infections occur early, fruit spots become scablike with age and the fruit may
become misshapenand unsightly, rendering them unusable.
• The pathogen overwinters primarily in infected leaves on the ground. Primary spores
are discharged from fuiting bodies on dead leaves during spring rains and infect
young leaves and fruit during periods of prolonged moisture. These infections
produce secondary spores, which may cause further spread of disease during wet
periods.
• Overwintering twig lesions from secondary infections may also be an important
source of innoculum in spring.
• Late-season infections, which appear as black, velvety pinpoint spots on fruit and
leaves, generally can be tolerated in backyard trees because peeling fruit removes
the scabs, and fruit are less likely to be deformed.

Botrytis (Gray Mold)
• Fruiting gplants affected by Botrytis include: Stone Fruit,
Caneberries, Grape, Citrus, Guava, Strawberry, many others.
• Infects flower petals, young leaves & especially fleshy fruit.
Touching fruit spread disease. Spores are spread in dust-like
clouds
• Likes high humidity & moisture. Favors cool – warm spring &
summer rainy weather. Occurs at temperatures of 32 –80
degrees.
• Maintain good air circulation and sanitation! Topping or
heading trees can result in poor air circulation and can
promote this disease!

Fire Blight
• Fruiting plants
affected by Fire
Blight are: Apple,
Pear, Quince and
Loquat

Fire Blight
• Fire blight, caused by the bacterium Erwinia
amylovora, is a common and frequently
destructive bacterial disease of pome fruit trees.
Pear and quince trees are extremely susceptible.
• Fire blight infections can destroy limbs and even
entire shrubs or trees.
• Disease symptoms can appear as soon as trees
begin active growth. The first sign is a watery, light
tan bacterial ooze that exudes from branch, twig,
or trunk cankers . The ooze turns dark after
exposure to air, leaving dark streaks on branches
or trunks.
• Cankers may be inconspicuous and infections may
not be noticed until later in spring when flowers,
shoots, and/or young fruit shrivel and blacken.

Fire Blight
• New infections usually first enter through the flowers. Infected flowers and
flower stems wilt and turn black on pear trees, whereas on apple trees they
turn brown.
• Blight infections often move into twigs and branches from infected blossom
clusters, causing small shoots to wilt, forming a crook at the end of each
infected shoot.
• Eventually the infected portion of the shoot turns black. Dead, blackened
leaves and fruit cling to branches throughout the season, giving the tree a
scorched appearance, hence the name "fire blight."

Fire Blight
• The bacteria can be transmitted to nearby blossoms or succulent growing shoots by
splashing rain or insects, especially honey bees. Injuries caused by wind, hail, or
insect feeding to succulent tissues are easily invaded by fire blight bacteria.
• Ideal conditions for infection, disease development, and spread of the
pathogen are rainy or humid weather with daytime temperatures in the range
of 75° to 85°F, especially when night temperatures stay above 55°F.
• Once fire blight bacteria enter the blossoms, they may cause only a localized
infection and eventually die, or they may move into the twigs and branches.
• Fire blight bacteria that survive generally do not move through the bark uniformly
but invade healthy wood by moving in narrow paths up to 1-1/2 inches wide in the
outer bark ahead of the main infection. These long, narrow infections may extend 2
to 3 feet beyond the edge of the main infection or canker.
• Vigorously growing shoots are the most severely affected; therefore,
conditions that favor rapid shoot growth, such as high soil fertility and
abundant soil moisture, increase the severity of damage to trees.

Fire Blight Control
• Eliminate fire blight infections by pruning out diseased branches. Always cut an
infected branch at least 8 to 12 inches below the visible injury or canker.
• If a fire blight infection occurs on a trunk or major limb, the wood can often be saved
by scraping off the bark down to the cambium layer in infected areas. When
scraping, look for long, narrow infections that may extend beyond the margin of the
canker or infection site. If any are detected, remove all discolored tissue plus 6 to 8
inches more beyond the infection. If the limb has been girdled, scraping will not work
and the whole limb must be removed.
• To avoid spreading bacteria during pruning, dip or spray the pruning tool before each
cut with a 10% solution of bleach (one part bleach to nine parts water).
• A very weak (about 0.5%) Bordeaux mixture or other copper fungicide applied
several times as blossoms open can reduce new infections, but will not
eliminate all new infections nor those already existing in wood. The number of
applications needed depends on the blooming period. Once blossoms begin to open,
make the first application when the average temperature exceeds 60°F. Apply at 4-
to 5-day intervals during periods of high humidity and until late bloom is over. For
pear trees, this may mean five to twelve applications per season.

Fig Mosaic Virus
• Host specific, only affects figs. Formerly considered benign, probably
causes crop reduction.
• Symptoms resemble potassium deficiency. Leaves may be smaller than
normal and deformed. Premature defoliation and fruit drop often occur.
• Virus spread by cuttings and by eriophyid mite.
• Black Mission is the most seriously damaged cultivar.
• There are no cures for virus diseases.

Fruit Thinning
• Fruit should be thinned to prevent overbearing and
potential limb breakage on trees. Leaving fewer fruit
will result in larger, better quality fruit.
• Thinning fruit should be done when fruit is about the
size of a dime or a nickel.
• Fruit clusters should be thinned to only one or two fruit.
• Fruit should normally be thinned so that fruit are about
Fruit should normally be thinned so that fruit are about
two to four inches apart.

Pruning for structural strength, tree
health, fruit production and size
Traditional pruning methods have frequently
emphasized fruit production while sacrificing tree
health and long tree life. Skills needed to prune
trees properly take time to learn and training to
develop.
Instead of following pruning principles that promote
tree health and long tree life, it is a standard
practice and is often considered easier and
more “cost effective” to replace the trees after a
relatively short period of time (10 – 20 years).

Recent research on pruning by Richard Harris and
Alex Shigo (among others) has taught new
principles i and given new insights i on how plants
respond to pruning and how pruning affects tree
health.
This research has been adopted by the International
Society of Arboriculture to establish new and better
pruning standards for the way we should prune
trees.
Using these principles to prune fruit trees can
increase tree longevity and fruit production while
reducing maintenance costs as well as help to
reduce pest and disease problems on our fruit
trees!

Training
• Training branches to grow in specific directions is often a viable option to pruning.
This can take advantage of growth which h has already developed d instead of pruning
off already grown branches and waiting for new branches to grow.
• Using training techniques can avoid the wounds made by pruning and therefore
reduce the problems associated with those wounds.
• Training should be done when branches are young and flexible enough to
bend into shape without breaking or splitting the branch or trunk. Weights,
guy wires, stakes or spreaders can be used to train branches.
• If ties are used, the tie material should be at least 1" wide wherever it comes into
contact with the bark of the tree to prevent damage to the bark.

PRUNING:
• A pruning cut is a wound that is a possible entry point for
decay, diseases or insects.
• Plants "heal" a wound by a process called
compartmentalization. This process surrounds the wounded
area both internally and externally with tissue that has greater
resistance to decay. The wounded area never grows back
together and this wound remains a weakened area for the life
of the plant.

• Cutting a small branch
and making a small
wound is always more
desirable than cutting a
larger branch and
making a larger wound.
Larger wounds take
longer to "heal" (or
compartmentalize) e) and
have greater potential
for attack by decay
organisms, diseases
and insects.
PRUNING:

Pruning Sealers
• Although h pruning sealers have commonly been recommended d to use on
pruning wounds, studies have shown that these products are not
beneficial and should not be used!
• At best, they are purely cosmetic and do no good.
• At worst, they trap disease organisms against the wounded area and
encourage disease and decay as well as impair i the ability of the tree to grow
over the wounded area and compartmentalize the wound!
• Do not use these products when pruning your trees!

REASONS TO PRUNE
Structural Strength:
• Pruning for structural strength is
especially important on fruit trees. Heavy
crops of fruit can easily break branches,
severely damaging main scaffold limbs or
splitting trunks. Basic guidelines for
structural pruning are as follows:
• Train scaffold branches to be spaced
along the trunk both vertically and radially
when trees are young.

REASONS TO PRUNE
• Increase the crotch
angle of branches
to greater than 30
degrees by
spreading branches
apart or by pruning
off one of the
branches.
Structural Strength:

REASONS TO PRUNE
Structural Strength:
• Remove co-dominant leaders by removing or reducing one of the branches.
• Occasionally one of the branches can be redirected into a lateral branch by
spreading the branch. This redirected branch will no longer be co-dominant.
The crotch angle should be spread to 30 degrees or larger.

REASONS TO PRUNE
Structural Strength:
• Prune off branches which are attached to the
bottom side of attached branches. (Unless this is
going to become the new terminal end of the
branch.)
• If these branches break, ripping or tearing of the
bark of the supporting branch often results.

REASONS TO PRUNE
Health:
• Prune off the four D's: Dead, Damaged, Diseased and Dysfunctional
branches.
• Dysfunctional branches are branches which are pointing towards the ground
or are crossing or rubbing other branches.

REASONS TO PRUNE
• Prune to leave flowering and
fruiting wood for specific fruit
types. (Fruiting spurs, last
season's growth/ one year old
wood, or current season's
s
growth.)
Fruit or Flowers:
• Thin branches and
fruiting wood to allow
adequate light
penetration and air
circulation for proper p fruit
development for each
fruit tree type.

Prune for Fruit Production
Fruit trees may bear fruit on fruiting spurs, as in plums, apricots apples and pears; on last years
growth, as in peaches, nectarines, and some figs, or on current season growth, as in figs,
mulberries and pomegranates.
It is extremely important to know the fruiting habits of the fruit tree you are pruning in order to
be able to prune correctly and to maximize fruit production.

FRUITING HABITS OF COMMON
Current-Season's Shoots
• Fig — second crop
• Mulberry
• Persimmon
• Quince
• Walnut
FRUIT AND NUTS
Previous-Season's Spurs and Shoots
• Apple — minor
• Apricot and Aprium - short-lived spur
• Cherry, sour
• Pear — minor
• Pomegranate
Previous-Season's s Shoots
• Fig — first crop
• Filbert
• Nectarine
• Peach
• Pistachio
• Quince
Long-lived Spurs
• Almond
• Apple
• Cherry, sour
• Cherry, sweet
• Jujube
• Pear
• Pecan
• Plum, European
• Plum, Japanese
• Pomegranate

REASONS TO PRUNE
Shape:
• Prune trees to
specific shapes
for best fruit
production.
• Open vase or
modified open
vase for trees in
the genus Prunus.
• Central leader or
modified d central
leader for all
others.

Open Vase
• The open vase style resembles a
bowl or vase.
• Scaffold branches and
secondary scaffold branches
make up the sides of the bowl.
• All branches that t grow towards
the center of the bowl are
shortened or removed to allow
light and air to reach the interior
of fthe tree.

•The modified open vase pruning
style differs from the open vase style
by having more than one level or
layer. Each level or layer is made up
of a smaller "bowl" above and within
the larger, lower bowl.
• Sufficient distance must be
maintained between these layers to
allow for good air circulation and good
light penetration to the lower layer or
layers.
•Large trees can have up to 3 layers,
so that the overall appearance of the
tree resembles candelabra. This
results in a larger tree and greater
fruit production than the open vase
style.
Modified Open Vase

Central Leader
• Except for the stone fruit, all other
fruit trees are generally pruned to a
central leader or a modified central
leader shape.
• A tree pruned into a central leader shape
resembles the shape of a Christmas tree.
Pruned to this shape, the tree will be the
tallest and will produce the greatest
amount of fruit.
Central Leader

Modified Central Leader
• The modified d central leader pruning style differs from the central leader by
having a more rounded top. The dominant leader of the central leader tree
is suppressed with drop-crotch pruning or training techniques and secondary
leaders are allowed to develop. Each outer leader becomes progressively
shorter as they move outward from the center of the tree.
• These secondary leaders divide the growing energy or dominance between
several growing points and the overall effect is a lower growing tree with a
more rounded shape.

Shape:
• Many fruit trees can also be pruned or shaped for specific
function in the landscape such as shade or patio trees,
hedges, screens or espaliers.

REASONS TO PRUNE
Direct or Redirect Growth
• Manage the growth in the tree so
that one branch or side of the tree
does not overgrow the other
portions of the tree and so that the
tree keeps a balanced shape.
• Prune to a terminal branch to direct
growth in that direction.
• As branches bend downward from
the weight of fruit, foliage, or wood,
they often need to be pruned back
into an upright growing position.
Use drop-crotching pruning
techniques to a side or top branch
to redirect growth.

REASONS TO PRUNE
Direct or Redirect Growth
• As branches bend downward,
redirect growth using drop-crotch
pruning techniques to a side or top
branch to redirect growth upwards.

• Fruit trees which are
pruned to their maximum
size will produce the
greatest amount of fruit.
These trees are pruned
into central leader or
modified open vase
shapes.
REASONS TO PRUNE
Size:
• To keep fruit trees
smaller for ease of
picking the fruit, to get
more trees into an area,
or because of space
limitations, prune to
modified central leader
or open vase shapes.

Never top or head branches or trees!!!
• Topping or heading has many harmful effects on tree growth and tree health. The
results include excessive, poorly attached branch growth, disease and decay, and
starvation among others and never results in reducing the size of the tree long
term!
• The only
exception is
when you are
pollarding a tree
or creating a
hedge.

Never top or head branches or
• Reduce the height or
width of a tree, or the
length of a branch with
thinning cuts by the
pruning technique
known as dropcrotching.
trees!!!

• Drop crotch pruning is to
prune a branch by dropping
back from the apical tip to a
lower lateral branch. This
lateral branch should be at
least 1/3 the diameter of the
branch which is being
removed.
• A pruning cut is then made
at the top of the collar of the
lateral branch.
Drop Crotch Pruning

Drop Crotch Pruning
• Each branch is pruned
individually, reducing the height
or width of the entire tree.

REASONS TO PRUNE
Managing Suckers: (Root Suckers)
• Most deciduous fruit trees are grafted.
• All growth arising below the graft or from the root system should be
removed to prevent the root stock from dominating and dwarfing out or
killing the desired grafted tree.

REASONS TO PRUNE
Managing Water Sprouts:
• Water sprouts are vigorously growing upright shoots arising from above the graft
union on grafted trees.
• In some cases, water sprouts can be trained to form strong branches and may be
beneficial.
• If water sprouts are excessively crowded have narrow crotch angles are crossing or
If water sprouts are excessively crowded, have narrow crotch angles, are crossing or
rubbing, or are causing poor branch or tree structure, they should be removed.

Timing:
• Improper timing can predispose plants to attack by insects,
diseases, or damage from sunburn or sunscald.
• Most pruning should be done during the winter months on
deciduous fruit trees when the trees are dormant and when
insect populations are suppressed by the winter cold.
• In some cases, lighter summer pruning can be beneficial for
keeping trees smaller, however many bark boring insects are
promoted by summer pruning. If these insects are common in
your area, keep summer pruning activities iti to a minimum.
i

Deciduous Fruit Trees in
Southern California
Tips for Growing and Selecting