Trichogramma are tiny wasps that kill the eggs of Lepidoptera.
Most agricultural plants are attacked at some point during the growing season by one or more species of Lepidoptera and most agriculturally important Lepidoptera are moths. Moths are adult insects and they usually feed on nectar produced by plants and honeydew produced by certain insects. Moths do not attack plants, but serve only to lay their eggs. Moth eggs hatch into caterpillars, the juvenile form of Lepidoptera, and these are the primary forms that damage plants by feeding on the fruits or foliage. Examples of such caterpillars include corn earworms, cabbage loopers, codling moth caterpillars, and navel orangeworms, to name a few.
In years past, caterpillar control was usually achieved by application of insecticides. However, many insecticides now fail to control these pests. Excessive use of insecticide has led to resistance or tolerance to many insecticides by caterpillars and many non-target secondary pests, such as aphids and spider mites, which then become uncontrollable primary pests. In addition, public outcry against the use of insecticides on food crops, and the excessive costs for producing better insecticides has led to a decline in the insecticide industry and many of the most effective insecticides are now banned from use in agriculture. However, a few insecticides are still useful and acceptable and continue to have a place in agriculture. It is in the best interest of agriculture to extend the efficacy of our remaining insecticide arsenal by using these only when absolutely necessary. New, effective, and acceptable insecticides are available in ever decreasing numbers – but all is not lost!
In many situations, low levels of caterpillars can be maintained at economically acceptable levels by use of alternative methods of control. One such method is the augmentative release of commercially available species of Trichogramma. Trichogramma are tiny wasps that kill the eggs of Lepidoptera. Trichogramma accomplish this by laying one or more of their own eggs inside the much larger eggs of Lepidoptera. The Trichogramma egg hatches into a small larva, which feeds on the inside of the moth eggs, thereby killing it. After 8-10 days of feeding and developing, an adult Trichogramma wasps chews out through the shell of the moth egg. It then mates with a Trichogramma of the opposite sex and begins searching for fresh Lepidoptera eggs in which to lay it’s own eggs.
The key to management of Lepidoptera with Trichogramma begins with a thorough knowledge of the life cycle and behavior of the caterpillar pest. The grower must know when moths first begin egg laying. Release of Trichogramma must coincide with this time period. Often the release period is the same period when insecticides are used for control. Sometimes, first releases are made prior to that time. Multiple releases may be necessary during several time periods of a growing season. Our supplier produces several species of Trichogramma. These include T. pretiosum, T. brassicae, T. platneri/minutum and T.ostriniae. The proper procedure and frequency of release may vary considerably, depending on the target caterpillar species, their density, the crop habitat, and the cultural practices in use.
The first step is to carefully plan your Trichogramma release schedule. Remember, releases should be started when pest moths first appear. Control with Trichogramma is not a ‘quick-fix’ solution and is not recommended for ‘out-of-control’ populations of caterpillars.
We will need to know the number of acres and the species of caterpillar involved. Then we can help you decide on the best species of Trichogramma for your situation, the number that should be released per acre, and the number of releases per season. Little or nothing will be gained by releasing in only a small part of a larger planting. Moths will only migrate from the untreated areas into the release area and the Trichogramma will not be numerous enough to provide effective control. You will not be able to see the difference without a complete control program. With the information required above, we will be able to help you plan a program and the Trichogramma will be shipped to you automatically. We guarantee the highest quality Trichogramma and service available.
Most insecticides are very harmful to Trichogramma adults. However, the eggs, larvae, and pupae are afforded some protection from insecticides by the moth egg shell in which they are enclosed. Even so, it is not wise to apply insecticides during the time period when Trichogramma are used. Also, it is important that the grower has a good understanding about the residual life of all insecticides that may be used during the growing season. Insecticide should be used only when caterpillar number are “out of control”. Trichogramma should be used to maintain caterpillars at or below economically important levels. Don’t forget, aphids, mites, and other secondary pests will be less abundant when insecticides are not used.
We sell Trichogramma on Ephestia kuehniella, which is a larger host egg compared to the commonly used Sitotroga cerealella. Parasitized moth eggs are black in color. Trichogramma are loose or glued to hanger cards.