Greenhouse

If in tomato crops the whitefly is controlled by the parasitic wasp Encarsia formosa and besides pests like the silver Y moth or the golden masked owl occur,  Trichogramma may be used in addition to Bacillus thuringiensis preparations. When controlling owlet moths in herbs and vegetables, Trichogramma parasitic wasps have the additional advantage that no residues or leaf spots are caused that even with biological preparations cannot always be excluded. In tropical greenhouses or zoological gardens, usually the use of chemical agents is not possible because of the animals and insects living there but also because of the visitors.

In greenhouses there are generally warm and humid climatic conditions - perfect not only for the growth of plants but also for many pests! This also includes harmful moths. Trichogramma parasitic wasps may be used to control them.

Visitors, animals and insects, long opening hours, open waters in display greenhouses - all these are factors that strongly limit or even make impossible the use of chemical plant protection products, also of biologically effective ones. The use of egg parasites to control the harmful moths is a good alternative here, especially since several other beneficial insects are already used here for control.

For the successful control it is important to know the existing species. You are welcome to send us pictures or the pests found (moth, caterpillar, pupa), alive or dead, for analysis. Securely pack the samples in boxes or fix them with adhesive tape on paper. We will check as soon as possible what kind of pest it is.

Monitoring with pheromone traps

By means of species-specific pheromone traps it is possible to catch male moths but also to determine a date for the use of Trichogramma parasitic wasps.

Trichogramma collection

With more than 30 species and about 200 strains from different locations and from different pest eggs, we have one of the biggest collection of Trichogramma-species worldwide. For the determination and maintenance of this breed collection we realize a molecular genetic identification of species (ITS-2 PCR), as the microscopic beneficial insects (about 0.4 mm) are difficult to determine with the microscope. This family is worldwide the best studied group of beneficial insects because it can already be used against the eggs of the lepidopteran pests and it works faster than any other control agent.

We are therefore able to quickly test appropriate Trichogramma-species when new lepidopteran pests occur.

We also support university research with this extensive living collection of Trichogramma, including studies on the basic research in the biology and ecology of Trichogramma. Our partners include Freie Universität Berlin, the universities in Bremen, Stuttgart-Hohenheim, Freiburg, Halle or also international partners in DK-Kopenhagen, NL-Wageningen, ES-Almeria, the University of Cairo or colleagues in the Middle East.

Apart from the practical use, research and further development of the procedure are important to us. We are partner in various research projects both in plant protection and stored product protection. In cooperation with the Julius Kühn Institute, the DLR, but also the Fördergemeinschaft Ökologischer Obstbau e.V. (Föko) important further developments have been driven forth.

Tropical greenhouse

Lepidopteran pests in vegetable cultivation have already been controlled for decades with Trichogramma parasitic wasps. These lepidopteran pests are also found in the cultivation of ornamental plants or in the display gardens under glass. The species occurring in the tropical greenhouse differ, however, according to plant community and operation. The climatic conditions are often similar so that Trichogramma is also increasingly used here. Some pests appear more frequently now like the European pepper moth Duponchelia fovealis and in the last years increasingly also the tomato looper Chrysodeixis chalcites.

Especially display gardens or zoological gardens with a lot of visitors or zoo animals benefit from the biological pest management as the use of beneficial insects can take place without residues and disturbances during operation. As with the use in horticultural greenhouses, Trichogramma parasitic wasps complete the established range of beneficial insects in the biological pest control.

Newly imported or introduced lepidopteran pests increasingly occur. In our laboratory we test their possible control with Trichogramma and develop appropriate control concepts. If necessary, it is also possible to use a mixture of different Trichogramma parasitic wasps against the different damaging moths occurring in the tropical greenhouses.

Trichogramma parasitic wasps

The use of Trichogramma is one of the oldest biological control methods in Europe. Already in the early 1970s, egg parasites were spread on the first corn acreages in order to control the European corn borer. The roots of our company also lay in the early stage of the biological control of the European corn borer in the 1980s.

Over the years the biological control was extended to codling moths and plum fruit moths, as well as to various pests in the greenhouse growing of vegetables or ornamental plants and in the meantime to lepidopteran pests in tropical greenhouses. About 15 years ago, the use of Trichogramma in the stored products protection was developed together with a partner.

Target pests for Trichogramma are the Indian meal moth (food moth), the common clothes moth and the casemaking clothes moth that can be effectively controlled by the use of beneficial insects. Regularly new damaging moths occur. We test the possibility to control them by Trichogramma and develop appropriate control concepts.

Interaction Trichogramma parasitic wasp and target pest

The only 0.3 to 0.4 mm small Trichogramma parasitic wasps are natural antagonists of numerous lepidopteran pests. The tiny hymenopterans parasitize pest eggs, that is, they occupy them with their own eggs. The pest egg is eaten up while a little beneficial insect develops inside. After about 10 days, a young parasitic wasp hatches from the killed moth egg and looks for further moth eggs.

 The cycle repeats as long as there are pest eggs. Naturally occurring populations are not sufficient for a successful control. A seasonal settlement is also only possible in a few cases. Therefore, the beneficial insects are bred en masse and targetedly released every year during the oviposition of the target pest.

In Germany at the moment 10 naturally occurring Trichogramma species are known. Of these we breed 4-5 species in large quantities and use them commercially. There are about 150 known Trichogramma species worldwide from which about 20 species are used for biological pest control.

The Trichogramma parasitic wasps may also be used against pests like

  • Bee moths in bee colonies and bumblebee boxes for the pollination in greenhouse growing

Application systems TrichoKarte and TrichoKugel

TrichoKarte and TrichoKugel have proven to be optimal application systems. They contain parasitic wasps in up to 10 different stages of life, in order to hatch in a period of two to three weeks depending on species and target pest.

Expertise and long-term experience

The team of AMW has many years of experience in the breeding of Trichogramma. Through the own development of new mass breeding systems and mechanical manufacturing techniques, today we are able to supply large quantities within a very short time.

Besides the mass breeding, in our laboratories we maintain a collection of more than 200 strains of 30 different Trichogramma species that amongst others come from outdoors baiting and collected pest eggs. Interesting breeding lines are checked by us in extensive laboratory tests and field trials in terms of their appropriateness for the control of damaging moths. In this way suitable antagonists of cabbage moth, codling moth etc. could already be determined.

The molecular biological identification of Trichogramma parasitic wasps

For the quality control of Trichogramma, criteria like number, lifetime, number of offspring, host acceptance and host preference are evaluated.
The morphological determination of the only 0.4 mm small Trichogramma parasitic wasps that are used against damaging moths in plants and also in the stored product protection is very difficult, because a preparation of the male genital apparatus must be carried out for it.
Due to species-specific host and habitat preferences of the individual Trichogramma species and the related suitability to control a specific pest, the taxonomic determination of the Trichogramma is indispensable.

In-house examination by PCR

The molecular biological examination by PCR is a possibility to reliably identify the different Trichogramma species. We regularly examine the Trichogramma species in our laboratory for different quality parameters and thus optimize the effectiveness for the control.

The beautiful pictures and movies of Trichogramma are the result of a cooperation of Mister Prof. Urs Wyss, University of Kiel and Bernd Wührer for the short movie on the Biology of Trichogramma parasitic wasps.

Monitoring, important for the successful control

The first important step for a successful control of moths in greenhouse growing is the so called "monitoring", the catching of the harmful moths with pheromone traps (or light traps) to determine the degree of infestation.

By means of species-specific pheromone traps that bear the attractant of virgin female moths in replaceable dispensers, it can be determined if and which moths are being active. As the traps do not catch female moths and only a part of the existing male moths, this is a mere measure to monitor the moth flight and to determine the dates of control. If male moths fly around, then the egg laying females are also around.

Distinguish the moths species with pheromone traps!

There are pheromones for many different harmful moths now that fly around in greenhouses. If a new pest appears that is difficult to identify, we would be pleased to assist you with the determination, as a successful control depends on it. The biology, development times and the knowledge about preferred host plants are important informations when deciding on the best control strategy.

The use of pheromone traps is easy to handle. The pheromone traps, usually they are so-called delta-traps, are simply opened to a roof, set up or hung and after equipping them with the pheromone bait they are ready for use. The attractant should be replaced regularly with a fresh dispenser. Per room only one trap should be used so that the moths can orientate themselves to the scent. If there are too many traps, this leads to a disorientation of the males, in the fragrance they cannot localize the trap anymore. The selection of the location of the trap is also important: Fresh air is often less disturbing than the windless corner in the greenhouse in which the pheromone-cloud stands still locally limited.

The right use of the trap is important because the activities of the pest should be evaluated. A wrong location or interfering  pheromone dispenser may easily lead to misinterpretations and therefore also endanger the success of the Trichogramma use.

Control and document the catches of the traps!

The hung traps have to be controlled regularly to register the start of the moths flight - also "zero" is important, the time before the moths flight starts. Trichogramma is an egg parasite and has to be released when the moths fly and lay their eggs.
It also makes sense to regularly record the catches of the trap in a data sheet or calendar in order to obtain a flight status. With the data it is possible to determine if the control has worked. Even after a control the traps should kept in use in order to detect a new infestation in time.

Combinable with the use of parasitic wasps

The pheromones last up to half a year, but can lose their full effectiveness, depending on environmental conditions, already before this. The attractants for moths are completely nontoxic and are also of no interest for the Trichogramma parasitic wasps. The parasitic wasps orientate themselves by the smell of the laid eggs and the traces that the female moths leave when landing and laying eggs.