Managment Strategies and Tactics
EXCLUSION
Growers need to make every effort from the beginning of a crop until
been used in agriculture for many purposes, but the primary use has been
production by covering the narrow raised beds in a full-bed polyethylene
mulch production system.
SANITATION
Sanitation is closely related to exclusion and should be practiced to
manage insects and mites as well as diseases. The following practices are
strongly recommended:
• Burning, burying, or hauling away all leftover roots and other plant
parts so that there is no chance that insects in the egg, larval,
nymphal, pupal, or adult stages could remain in the greenhouse.
• Sanitation must be practiced not only during preplant times but
also throughout the growing period. Workers should immediately
dispose of plant parts generated by pruning, such as leaves and
stems. Culls (undesirable) or overripe fruit should be removed from
the greenhouse and surrounding areas. Insects are often attracted
to and can live for long periods on these plant materials.
• Weeds should not be allowed to grow around or within the greenhouse.
A 10–30-ft vegetation-free zone around the greenhouse
can be created with a heavy-duty geotextile weed barrier material
typically used in the container nursery industry as a groundcover.
• A clean transplant program will aid in keeping pests out. Plants
coming from other locations should be carefully inspected for
insects, mites, and diseases and temporarily quarantined until it is
clear that the plants are free of pests. Workers should avoid wearing
yellow clothing because it is highly attractive to insects, which may
hitch rides into the greenhouse or from one greenhouse to another.
BIOLOGICAL CONTROL
Biological control in the greenhouse environment means providing or
releasing insect or mite predators, parasitoids (specialized parasites that
ultimately kill their hosts), nematodes, or disease-causing organisms (fungi,
bacteria, and viruses) that attack insect pests. Some biological controls
cannot be used with most insecticides. Reducing or eliminating chemical
pesticides leads to a safer working environment, can reduce production
costs, and, in the case of organic production, can result in premium prices
for the crop. Biological control, however, is much more management-intensive
than conventional insecticides and miticides, and requires a greater
knowledge of pest biology and pest numbers. Many factors contribute to the
success or failure of biological control: type and quality of the natural enemy
selected, release rates, timing, placement, temperature and humidity, and
the previous use of insecticides and miticides.
Suppliers can provide technical advice on the optimum use of their
products. Some have detailed websites. In general, releases must be made
better adapted to particular temperature and humidity conditions than
others, and some do better on some crops than others. The life span of the
parasitoid or predator will determine how often it has to be reintroduced. It is
important to note that if all the pests are eliminated, the natural enemies will
the life of parasitoid wasps. Yellow sticky cards may have to be temporarily
removed to avoid trapping predators and parasitoids.
INSECTICIDES AND MITICIDES
Even when a good biological control program has been established,
there may be times when a conventional insecticide or miticide is needed.
Biorational insecticides, such as insecticidal soaps, oils, neem products, and
Bacillus thuringiensis
although active against pest species. Systemic insecticides, insect growth
regulators, and pheromones used for mating disruption also fall into this
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sects and not others. Oils, for example, are toxic to lacewing eggs and adult
parasitoid wasps, but have relatively little effect on adult lady beetles and
lacewings. Soaps are toxic to young lady beetle larvae. Neem and Bt products
are generally safe for use with natural enemies. Other advantages of
biorational insecticides are shorter reentry intervals and safety for workers.
Conventional insecticides and miticides also have a place in IPM, if it is
not feasible to use biological controls and if biorational insecticides do not
registered pesticides. The development of resistance to insecticides is more
likely if a product is used repeatedly. Therefore, pesticides with different
modes of action should be used in a sequence that will help prevent
resistance.
The following steps are suggested when using any pesticide:
Step 1: Choose the right insecticide or miticide.
insecticide or miticide be selected. Insecticides and miticides are sometimes
effective against one pest but useless against other closely related pests.
stage, while others may be effective against a different stage, or even
against all developmental stages. Properly identifying the pest and understanding
its biology and life cycle allow the grower to make wiser decisions
when choosing an insecticide or miticide. Growers should consult UF/IFAS
Extension resources, pesticide companies and dealers, published literature,
and, ultimately, the pesticide label, for helpful information.
Step 2: Use the correct amount of pesticide.
After choosing the pesticide, the grower must carefully read the label to
determine the correct amount to use. Sometimes this decision will be based
on the size or stage of the pest and whether the population is high or low.
For example, small caterpillars may require the lowest recommended label
rate, while large ones may require the highest.
It is critical that the quantity of pesticide be accurate; growers should buy
a set of graduated cylinders that are marked in ounces (oz) and milliliters
(cc or mL), as well as a set of good-quality measuring cups. Plastic syringes
(minus the needles) are very useful for measuring thick liquids, such as
suspension concentrate (SC) formulations. These are available in several
sizes from suppliers of animal feed. A scale is essential for weighing dry
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es, such as graduated cylinders, should have pouring lips and graduated
markings that enable accurate measurements. Plastic is generally safer
of chemicals and money, and the reduction or elimination of phytotoxicity
(burning).
Proper measuring devices also play an important role in the overall safety
and handling of pesticides. They aid in preventing spills of concentrated
materials. Pesticide concentrates are usually handled when the sprayer is
loaded and diluted sprays are being prepared. Special handling precautions
are necessary at this time. The applicator must be particularly careful in
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ous concentrated material. Workers must be mindful, cautious, and use all
pesticides according to the label.
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