Pest
Management
IV. Conventional Pesticides
Relatively few
conventional pesticides are registered for greenhouse tomato production,
and this situation is not likely to change. If anything, fewer new materials
are likely to be registered, and older materials are likely to become
less effective as pests develop resistances. There are also detrimental
effects of most pesticides on bumblebees and introduced beneficial insects.
Thus growers should adopt integrated pest management practices rather
than relying exclusively on insecticides.
V. Cultural
Practices
The best way
to control insects is to prevent their entry through air intakes and entryways.
Placing screens directly over the air intakes would reduce circulation
too much, but screening boxes can be built out around the intakes to allow
air to circulate more freely. Charts available from screening manufacturers
allow calculation of the volume of these screening boxes. Double-entry
doors with positive pressure are the best way to prevent pests coming
in with workers. Within the greenhouse, pest populations should be monitored
with yellow sticky traps and control measures instigated as soon as adults
are detected. Great care should also be taken to avoid introducing pests
through infested transplants or ornamentals, which can be sources of
thrips,
mites, and whiteflies.
The best way to prevent diseases is to maintain a good greenhouse environment as discussed above: good air circulation, optimal plant temperatures, low humidity, and no dripping of condensate on plant leaves. In addition, plant wastes should be removed and destroyed promptly.