FEATURE ARTICLE

The Supplier Side of Biological Control for Greenhouses

Biological control of insect and mite pests is gaining in acceptance as rules and regulations, such as the Food Quality Protection Act (FQPA), are encouraging greenhouse managers to consider the potential use of biological control. In addition, applied and basic research has led to a better understanding of how to successfully use natural enemies under various environmental conditions and cropping systems.

Current applied research is emphasizing the use of biological control agents (parasitoids, predators, pathogens, and nematodes) in conjunction with "reduced-risk" materials (insect growth regulators, soaps, and oils), which supposedly have minimal effect on natural enemies, when implementing a biological control program.

Factors to consider when implementing a biological control program generally include releasing the appropriate natural enemy, releasing enough individuals, and evaluating the performance of released natural enemies. However, what is just as important is how to select a biological control company and what considerations need to be determined before actually releasing natural enemies. Biological control agents or natural enemies are reared in large quantities in colonies where they feed on a food source or a host that is foraging on plants or fruit. They are collected and then sent to the end-user.

Biological control companies are responsible for producing and distributing natural enemies. These can be distributors, producers, or both. Distributors generally don't rear their own natural enemies; they order them from a producer. Rearing natural enemies is costly, requiring space, time, and labor. Producers have the facilities to rear one or many different types of natural enemies, which they can send to distributors. Some biological control companies both produce and sell natural enemies to the consumer.

It is important to consider a number of factors when ordering and releasing natural enemies from a biological control company, begining with selection of a reliable company. Are the natural enemies consistently available; how far in advance do orders need to be placed; what about quality control, delivery speed and packaging? Is personal service and accessibility important to you? And what impact could contamination have on your control program?

Select a Reliable Biological Control Company: It is important to select a biological control company that you feel comfortable with. The best way to select a biological control company is through networking with extension agents, university personnel, and other greenhouse managers. Input from these contacts should help you determine the level of satisfaction provided by various companies. Once you find a suitable biological control company it is best to stay with them, especially if they are providing quality service.

Consistent Availability of Natural Enemies: Try to select a biological control company that is able to supply a wide-range of natural enemies and is able to provide them on a regular basis. It is important to realize that maintaining a consistent supply of natural enemies is not the same as ordering a pesticide container. Natural enemies are living organisms and sometimes fluctuations in the number of individuals available or particular stage (larvae or adult) vary during certain times of the year.

Order Well in Advance: It is best to order natural enemies at least 2 weeks in advance. This helps to ensure receiving a quality product. It takes time for a biological control company to prepare natural enemies before they are shipped to you. Also, the proper stage needs to be present in suitable quantities. Because of the time commitment, you simply cannot call the day before you want natural enemies delivered. If you are committed to implementing a biological control program, you should be aware of pest problems early through a consistent scouting program and thus order natural enemies regularly.

Quality Control: This concept cannot be reiterated enough. The bottom line is check natural enemies before releasing them. If you release poor quality natural enemies then this will result in poor control. When you receive natural enemies be sure to check them to determine if they are alive. For example, make sure adult parasitoids are flying around or predators shipped as adults or larvae are moving. Quality control of predatory mites such as Phytoseiulus persimilis shipped in containers consisting of bran or vermiculite involves placing a small sample on a white sheet of paper and check with a 10X hand-lens to make sure something is moving. Natural enemies that are shipped as eggs or pupae can be checked using a different method. For example, quality control of parasitoids such as Encarsia formosa, which are shipped on cards containing whitefly pupae can be determined by placing a sample card inside a glass container (e. g. an empty mayonnaise jar) and regularly checking to make sure that adults are emerging.

Delivery Speed: Most natural enemies don't have an abundant supply of food during shipping (some are shipped with no food), with the exception of natural enemies shipped as eggs or pupae. It is important that natural enemies be shipped so they are received the next day (through UPS or FedEx). Longer shipping times lead to higher mortality or reduction in fitness, which can reduce their effectiveness. In addition, the producer needs to respond to orders quickly so that you receive natural enemies on time. For example, if you order natural enemies from a biological control company on Monday and you receive them on Monday of next month, then I would strongly suggest selecting another company.

Packaging of Biological Control Agents: As mentioned previously, natural enemies are living organisms and they need to be handled very delicately. Natural enemies should be delivered to you in a container (preferably Styrofoam) with an ice-pack, and packed with either Styrofoam peanuts or newspaper to minimize movement during transit. This will ensure their survivability. Natural enemies that are improperly packaged may experience stress, which may reduce their effectiveness. In addition, natural enemies packaged poorly will result in you receiving dead insects/mites as opposed to live insects/mites.

Personal Touch: Chose a biological control company that wants your return business and is willing to help you succeed when implementing a biological control program. The way they can do this is by providing written information on the biology of natural enemies and pests, and instructions on release rates, time of application, and frequency of applications. This type of quality service will ensure that you are successful in your biological control program.

Accessibility: When selecting a biological control company make sure they have qualified personnel that are available to answer questions. This will ensure the success of a biological control program. However, in order to minimize frequent calling for information, you should have some background knowledge before undertaking any biological control program.

Contamination: This may be difficult for greenhouse managers to determine. However, natural enemies are living organisms and they can get "sick". Natural enemies are reared in colonies in close quarters in order to maximize efficiency. Any diseases or molds that occur may spread within a colony and infect a large number of individuals. Although natural enemies may appear healthy when you receive them, they may already be infected. Their physical and reproductive fitness may be impaired enough to reduce their effectiveness. If you suspect a problem or you receive dead natural enemies, immediately contact the biological control company, so they can take the appropriate measures to correct the problem.

Biological control companies try to produce and distribute a quality product. However, because they are dealing with living organisms unexpected problems may occur. It is best to work closely with a biological control company in order to succeed when implementing a biological control program in greenhouses.

- Raymond A. Cloyd, Univeristy of Illinois

The author wishes to acknowledge Carol S. Glenister from IPM Laboratories, Inc., for her comments and suggestions.


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