PLANT PROTECTION 1 – Pests, Diseases and Weeds

PLANT PROTECTION 1 – Pests, Diseases and Weeds
Conditions favoring (contd)
Climate change (Sutherst 2000).
As the limiting effects of rainfall are largely offset by
irrigation, the southern distribution of QFF is limited by
temperature. It is expected that the impact of QFF on
Australian horticulture will progressively increase over
the next few decades. With longer and more favorable fly
seasons leading to more generations per year and
reduced winter deaths, it is likely that QFF populations
will increase and become established over a wider area.
Potential consequences include:
Threat to the sustainability of area freedom in the
current Fruit Fly Exclusion Zones (FFEZ).
Increased damage and control costs for commercial
growers in endemic areas except northern Australia.
Increased damage to backyard growers
especially in SA and Vic. Thus the QFF poses a real
threat to southern states under modest projected
increases in temperature to the extent that the likely
cost increases raises doubts about the ability of some
industries in southern areas and remain viable.
Management (IPM)
There is a National Fruit Fly Strategy (NFF).
www.planthealthaustralia.com.au/fruitfly
1. Plan in advance and obtain advice for your
situation. Control measures vary according to where
you live, whether you are a commercial grower or
home gardener, etc.
2. Crop, region. Seek advice from local authorities to
ensure your plan is for your fruit crop in your region.
3. Identify the fruit flies likely to be found in you area.
Understand their life cycle, host range, how they
'overwinter', spread, etc. Is your fruit fly a pest species?
Consult a diagnostic service if needed (page xiv).
4. Monitor presence of male fruit flies using synthetic
pheromone traps in an area so that baits or cover sprays
may be timed more precisely. Use correct lure as some
fruit flies are not attracted to lures. Many fruit flies
caught in traps are native species. Exotic fruit flies
are trapped in northern Australia and in other in pest-free
areas. Fruit Fly Hotlines in SA may be contacted by the
public who find maggots in fruit from gardens or
bought from a shop.
Fruit should also be checked for stings (egg laying
activities) by female fruit flies.
Control activities can then be directed towards either
the eggs and maggots in fruit, or towards the adults.
Fruit flies may be so serious that monitoring may be
irrelevant, eg on guava in some areas.
Male annihilation. Traps with pheromones to attract
male fruit flies and an insecticide, help to reduce
numbers but do not satisfy quarantine regulations.
5. Thresholds. There is nil tolerance in a FFEZ and for
many export markets. To control and eradicate QFF and
MedFly in a FFEZ, treatment measures are prescribed.
Thresholds are available for some species of fruit fly,
they vary with the crop. How much damage can you
tolerate economically or aesthetically before you
implement control measures? Growers in some regions
must consider whether likely damage is sufficient to
warrant spraying.
6. Take appropriate action when a threshold is
reached (depends on whether it is a quarantine,
commercial grower or home garden problem. Keep upto-date
with official advice, information and legal
obligations. If in a FFEZ, immediately report sightings
of fruit flies to local authority/department of agriculture.
Costly suppression or eradication programs may be
under-taken by government/agricultural agencies.
Treat other nearby susceptible fruit crops.
Both cover sprays and bait sprays may be used
concurrently in commercial orchards.
Pre and post harvest treatments may be required to
gain entry to southern and export markets.
Contingency plans are in place for exotic fruit flies
should they be detected in any part of Australia.
Programs are available for organic growers, eg
Organic Farming : Managing Fruit Fly in Citrus
www.dpi.vic.gov.au/
7. Evaluation. Review your monitoring and treatment
records. Decide whether an improved program is
needed for next season.
Control methods
Each state/region has particular requirements for
the control of fruit flies and the local regulatory
authorities should be contacted for information
on control or if fruit fly is suspected. Control
measures for quarantine officers, local councils,
commercial growers and home gardeners vary
according to the region in which you live, ie if it
is a fruit-fly free zone (FFEZ), if fruit fly is a
major economic cost for commercial growers, if it
is an area where exotic fruit flies may enter, or if
it is in an area where fruit fly is a sporadic
problem not requiring control in some seasons.
Legislation.
It is the responsibility of the occupier of land to
prevent infestation by fruit fly. Each State/
Territory has particular requirements for the
control of fruit flies. Consult the appropriate local
authority for current regulations for the area in
which you live, these usually include sanitation
measures, quarantine regulations and insecticide
applications. There are also import/export
quarantine regulations. Search for fruit fly at:
www.aqis.gov.au/
Cultural methods.
Some climatic areas are not suited for the
continued development of fruit fly.
Grow early maturing varieties and harvest
before fruit fly populations build up.
Some commodities can be harvested at a mature
stage before they are susceptible to fruit fly.
Prune trees to a manageable size to facilitate
picking, spraying and baiting.
Cultivate soil around trees and keep weed-free.
Boil fruit for
at least
10 minutes.
Burn. Is this
permitted?
Immerse fruit in water
inside covered container
for at least 3 days.
Secure fruit inside a plastic
garbage bag. Expose bag
to sun for at least 3 days.
Fig. 42. Sanitation measures for treating fruit infested with fruit fly maggots.
70 Insects and allied pests - Diptera (flies)