Considerations when ordering and using commercially available natural enemies for biological control

Before ordering

■ Know the specific pests that you need to control. Identifying the pest as simply "whitefly"or "aphid" is not sufficient because different species of these pests require different natural enemies.

■ Determine the general level of infestation. If it is very high, it may be necessary to use other methods to reduce the pest population to allow biological control a better chance to be effective.

■ Know the best natural enemies available for the specific pests. In some cases, combinations of natural enemies may work better than individual species.

■ Know the proper timing of release of natural enemies, based on the life cycles of both the pest and the predator or parasite. Often in greenhouses there may be overlapping and continuous generations of the pest, resulting in the presence of the susceptible stage in its life cycle at all times.

■ Know the proper release rate for each natural enemy.

■ Calculate the amount of natural enemies needed, based on the release rate, the level of infestation, and the area to be covered.

■ If multiple releases are necessary, know the recommended frequency of release. A program of multiple shipments can be arranged with a call to your supplier.

■ Provide your supplier with a safe delivery address, where the shipment will be cared for as soon as it arrives and where it will not be exposed to temperature extremes.

■ Understand proper release practices so that you will be prepared to make the release as soon as the shipment arrives.

■ Know proper storage conditions in case release can not be made immediately after arrival.

■ Be sure all greenhouse vents are adequately screened to prevent escape of the released natural enemies (important for most insects, but not for predatory mites).

■ Do not apply broad-spectrum insecticides for at least 2-3 weeks prior to an intended release of natural enemies.

■ If you have questions about any of these matters, be sure to discuss them with your supplier. If you are just starting a biological control program, contact several suppliers initially and pick one that seems competent and professional in dealing with your specific pest problems.

When the shipment arrives

■ Minimize exposure to hot or cold temperatures.

■ Inspect the shipping container and contents for damage.

■ Determine if you received the species and quantities you ordered.

■ Attempt to assess the condition of the natural enemies.This is easier to do with larger insects shipped in mobile stages than with very tiny insects or mites, or with insects shipped as inactive eggs or pupae. Mobile natural enemies should not be stressed. It's not unusual for a few to die during shipping, but most should be in good condition.

■ Make release as soon as possible after receipt.

■ Store under proper conditions if it is necessary to delay release. In many cases, predatory and parasitic insects can be stored only a few days before they start to lose vigor and effectiveness.

■ Make releases based upon recommendations of your supplier. Releases should generally be made during a cooler part of the day.

■ As you are making releases, check once again for quality characteristics.

After release

■ Check during the following few days to see if the natural enemies appear to be active and searching for the pests.

■ Attempt to evaluate the impact by monitoring changes in the pest population and by checking for evidence of predation or parasitism (such as mummified aphids or parasite cocoons).

■ Keep records of your releases and their results. Biological control programs sometimes need modification and adjustment and your previous records will be essential in this process.

96 Glossary

Abiotic control. Those natural environmental factors that help control the numbers of a pest population that do not involve living organisms or life processes.Weather events that kill many insects, such as severely cold winters and heavy rains, are good examples of abiotic controls.

Action threshold. A level of pest population at which controls should be applied to prevent economic damage to the crop.See also economic injury level (EIL); economic threshold (ET).

Augmentation of natural enemies.

One of the three general approaches to biological control. It is the periodic release of captured or commercially produced natural enemies to supplement those that occur naturally; it increases the effectiveness of biological control. Also called augmentative biological control. See also inoculation; inundation.

Banker plant. An alternate host plant used to raise hosts and natural enemies in large numbers in a greenhouse for later movement into the crop.

Biological control. The management of pest populations by the purposeful manipulation of beneficial organisms called natural enemies. See also augmentation of natural enemies; conservation of natural enemies; importation of natural enemies; natural enemies.

Cocoon. A silken case formed by an insect larva as protection for pupation.

Complete metamorphosis. Type of insect development in which the insect passes through a pupal stage before becoming an adult.

Conservation of natural enemies. One of the three general approaches to biological control. It is the provision of food, shelter, and other needs for natural enemies, and the avoidance of practices that kill natural enemies or interfere with their beneficial activities, such as the use of broad-spectrum insecticides.

Cosmopolitan. Occurring throughout most of the world.

Diapause. A period of prolonged inactivity in insects.

Economic injury level (EIL). The population level at which pests cause economic damage if left untreated.

Economic threshold (ET). The pest population level at which control measures should be initiated to prevent the population from exceeding the economic injury level (EIL).

Ectoparasite. A parasite that feeds and develops on the outside of its host.

Endoparasite. A parasite that feeds and develops inside its host.

Entomopathogenic. Capable of causing disease in insects.

Exoskeleton. The external skeleton of an insect, composed of hard cuticle (the "skin").

Facultative. Organisms that normally are free-living but have the ability to adapt to a parasitic or semi-parasitic mode of life.

Frass. Fecal material and food fragments produced by an insect in feeding.

Gregarious parasite. A species in which numerous immature individuals develop within a single host.

Hermaphroditic. Having both male and female reproductive organs; the nature of an individual possessing both ovaries and testes.

Host-feeding. A form of prédation. Many adult parasitic wasps feed from the same types of hosts as they deposit eggs in. Although such wasps are usually described as parasites or parasitoids, these terms properly refer to the feeding method of the larval stage.The adult wasps may also be beneficial by preying on other individuals of the same species used as hosts for their offspring.

Hyperparasite. A parasite whose host is another parasite.

Importation of natural enemies. One of the three general approaches to biological control. Undertaken primarily by the U.S. Department of Agriculture, universities, and state departments of agriculture, importation involves seeking natural enemies in the native home of the pest, and introducing and permanently establishing these natural enemies in the pest's present habitat.This approximates permanent natural control.

Inoculation. A preventive method of augmentative biological control in which relatively small numbers of natural enemies are released periodically for sustained management of the pest population below damaging levels. Also called inoculative release. See also augmentation of natural enemies; inundation.

Insectary. A facility for rearing insects. The term is often used in biological control for companies that mass-produce beneficial predators and parasitic insects for release in augmentative biological control.

Instar. The stage of an insect between successive molts.

Integrated pest management (IPM).

The use of all available and appropriate methods to control pest populations in an effective, economic, and environmentally sound manner.

Inundation. A curative method of natural enemy augmentation that uses large-scale releases of natural enemies for the immediate reduction of pest populations that are at or near damaging levels. Also called inunda-tive release. See also augmentation of natural enemies; inoculation.

Larva (larvae). The immature form of an insect that undergoes complete metamorphosis; the stage between the egg and pupa. Compare with nymph.

Microbial insecticide. A commercial preparation of living microorganisms (such as bacteria, viruses, or fungi) that are pathogenic to specific groups of insects.These preparations can be mixed with water and applied with conventional pesticide-application equipment. Microbial insecticides are regulated as pesticides by the Environmental Protection Agency, so users must follow specific labeling and use guidelines.

Molt. The process of shedding the skin between developmental stages (instars).

Natural enemy. A beneficial organism that kills or interferes with pests. These are the biological components of natural control; when manipulated by people they are the essential components of biological control.The natural enemies of insect pests include predators (such as predatory insects), parasitic insects, and microorganisms that cause insect diseases.

Nymph. The immature form of an insect that undergoes simple metamorphosis. Between hatching and the winged adult stage. Compare with larva.

Oviposit. To lay or deposit eggs.

Ovipositor. The egg-laying structure of a female insect.

Parasite. An organism that derives its food from the body of another organism (the host). A parasitic insect spends its immature stages in or on the body of a host, which dies just before the parasite pupates. See par-asitoid.

Parasitoid. An insect that parasitizes and kills other insects. Many biological control workers prefer this term over parasite, which more properly refers to those types of organisms, such as fleas and lice, that do not kill their hosts.

Parthenogenesis. Egg maturation without fertilization. In some insects, offspring are commonly produced without the need of egg fertilization. This commonly occurs in the parasitic wasps and their relatives, where female offspring are derived from fertilized eggs and male offspring are derived from unfertilized eggs.

Pathogen. An organism capable of causing disease.

Pest resurgence. A pest outbreak that results from the elimination of the pest's natural enemies, such as after an insecticide application. Even though the pesticide may initially control the target pest, the pest can recolonize and reproduce rapidly because its natural enemies have been eliminated. Compare with secondary pest outbreak.

Pheromone. A chemical substance secreted by an organism that causes a specific reaction by other individuals of the same species. Often used in traps to lure insects for pest monitoring purposes.

Phloem. Plant tissue which transports food over long distances within vascular plants.

Proleg. A fleshy, unsegmented abdominal leg of caterpillars.

Pupa (pupae). A nonfeeding, inactive stage during which an insect changes from a larva to an adult.

Puparium (puparia). A protective case created by the hardening of the larval skin in which the pupa develops. Produced by flies.

Secondary pest outbreak. A rapid increase in the population of one pest that occurs after treatment for another type of pest.The increase results from the elimination of the natural enemies of the secondary pest, as after insecticide application. Compare with pest resurgence.

Simple metamorphosis. Type of insect development in which the insect does not pass through a pupal stage before becoming an adult. Immatures are similar in shape to adults, but they are smaller and lack wings. Also called incomplete metamorphosis.

Solitary parasite. A species in which only one individual develops within a single host. Compare with gregarious parasite.

Species. A group of interbreeding individuals or populations, similar in structure and physiology, that are different from all other groups and produce fertile offspring.

Thorax. The body region between the head and abdomen. Bears the wings and legs.

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