PLANT PROTECTION 1 – Pests, Diseases and Weeds

PLANT PROTECTION 1 – Pests, Diseases and Weeds
Control methods
Control in trees. No system provides total
control against termites, but risk of termite attack can
be minimized. For most horticulturists, termite
control is a specialist task and trained pest control
specialists should be consulted to identify, locate and
deal with the infestation. Incorrect or rough attempts
to control termites may cause the termites to withdraw
from the treated area, to another location, spreading the
problem. Standards are available for termite prevention
and control in buildings and structures.
Cultural methods.
During maintenance avoid mechanical injury to
trunks and limbs of trees.
The best treatment for all tree problems is to ensure
that the trees are as healthy as possible.
Sanitation.
Prior to planting clear old stumps, roots and timber
that might attract termites from within 100 meter
radius. Burn or completely remove tree stumps.
Clearing and cultivating land for dryland cropping
can eliminate termites from these soils.
After planting. Keep ground under trees free of
weeds and logs.
After attack. Check current legislation regarding
tree removal. Obtain professional advice from an
arborist (tree surgeon) to assess hazard and damage,
and under-take treatments, eg apply insecticide to
trunk. Find nest or colony, if possible, and destroy it.
Biological control.
Natural predators. Winged reproductives are eaten
by lizards, snakes, frogs, birds, ants, dragonflies and
other insects. Echidnas use the long, sharp claws on
their feet to dig open termite and ant nests and
subterranean galleries to feed on workers and soldiers.
Ants, some beetles and other insects feed on young
termites, eggs and termite wastes in termite nests.
Commercially available agents. may be able to
treat established infestations in the future:
– Green muscardine fungus (Metarhizium sp.).
– A nematode (Steinernema carpocapsae).
Resistant/tolerant varieties. CSIRO
releases timber durability ratings, termite hazard
potential maps and decay potential for the whole of
Australia to ensure that correct timber is used. Some
timbers have some resistance to some termite species,
eg Jarrah (Eucalyptus marginata) is resistant to
Coptotermes acinaciformis but susceptible to
Nasutitermes exitiosus. Resistant timbers will not
protect buildings.
Plant quarantine. Serious termites overseas:
Formosan termite (Coptotermes formosanus)
West Indian drywood termite (Cryptotermes
brevis) was first detected in Qld in 1964 but is not
established throughout the country. Infestations in
buildings are fumigated.
Physical & mechanical methods.
Destroy nests on the ground by breaking open and
burning (if local regulations permit).
Turn over compost regularly.
Insecticides.
Most insecticides used for termite control may
only be applied by Licensed Pest Control Operators.
Safety precautions prevent personal exposure to
insecticide.
Because of toxicity problems, fewer and fewer
insecticides are available for termite control.
Before or during planting. In areas of high
termite activity, nests should be found and destroyed,
planting holes and soil may need treatment.
After attack.
– Small trees and shrubs. When the tree itself
cannot be treated, insecticide may be pressure
injected to soil around the base of the affected tree.
– Large trees. Boring holes about 15mm in diameter,
sloping slightly downwards into the tree at several
levels above the ground. This will give you some idea
of the extent of the damage and decide whether the
tree should be treated or removed.
– Locate nest by probing the trunk, crown or
between the roots. Ideally, holes are drilled into the
hollow center of the trunk above the nest and
insecticide run or forced into galleries. If the nest
cannot be located, it may be necessary to drill into
the galleries and flood them with insecticide. Nests
high in trees made by arboreal termites may be
removed and insecticide run into the galleries.
– Suppressing or eliminating a colony. A bait
toxicant in timber or cellulose matrix can be placed
in a bait station or the colony indirectly by dusting
aggregated termites. Bait stations may be below and
above ground. The Sentricon Termite Colony
Elimination System acts as a monitoring device
to detect foraging termites. The bait can be
replaced with a bait toxicant when termites are
found. Following cessation of termite activity, the
bait matrix is replaced with wood and monitoring
resumed.
Table 36. Termites in trees, stumps – Some insecticides.
What to use?
NESTS IN TREES
Group 1B, eg Chlorpyrifos , Deter , Dursban (chlorpyrifos);
Maldison (malathion)
Group 2B, eg Termidor (fipronil)
Group 3A, eg Ambush (permethrin); Generex , EnviroGuard ,
various (bifenthrin); Prevail , Stedfast (alphacypermethrin)
Group 4A, eg Imidacloprid Termiticide, Premise Foam
(imidacloprid,
Group 15, eg Intrigue (triflumuron)
BAITS STATIONS
Group 15, eg Recruit , Sentricon (hexaflumuron);
Nemesis , Requiem (chlorfluazuron) termite bait;
Flurox Termite Bait (flufenoxuron)
When & how to apply?
Application by Licensed Pest Control Operators.
Make an effort to locate the nest.
Application by Licensed Pest Control Operators.
Licensed pest control operators will provide advice on
the location of bait stations and prepare a diagram of
buildings, grounds and trees etc., inspect fences etc.
Insects and allied pests - Isoptera (termites, ‘white ants’) 179