Warehouse - Food moths

Warehouse - Larval control

Warehouse - Beetle control

Warehouse - Trichogramma parasitic wasps

Warehouse - Monitoring


Pests that damage stocks like the grain weevil cause worldwide damage running into billions. A control reduces losses of valuable food or seeds. For decades the chemical control of the storage pests in the warehouse had been standard. As only very few preparations are still approved, there is a demand for alternatives. For example, at the moment only one chemical agent for the treatment of empty spaces is approved. Apart from that, the cleaning is carried out mechanically using brooms and vacuum cleaner. Beneficial insects or silicate dust preparations may be used in the empty warehouse.

Besides the improvements in storage techniques (newly built warehouses, cooling technology etc.), the use of beneficial insects for the biological control of harmful insects is also becoming more and more interesting.

Many biological control methods have been investigated for years and some procedures have already established in practise. For many pest controller and warehouse keeper the use of beneficial insects is still new ground, but is finding increasing interest. Many areas are looking for new control methods respectively are already lacking control agents with fewer health risks.

With the use of beneficial insects, the idea of an integrated stored product protection is pursued: we seek a biological control with beneficial insects but also recommend in individual cases - if conditions of infestation are too extreme - the use of an insecticide in order to lower the level of infestation and to allow the use of beneficial insects the following year.

In the long term, only preventive control strategies and strict hygiene concepts can lead to success. As standard, this also includes a pest monitoring, that is not complex, but ensures continuous overview of the current activity of the pests in the warehouse.

The storage of cereals obligates to pest contol. Feedingstuff and raw food materials must be free from pests.

A well cleaned and kept clean warehouse has a good chance to remain free from pests for years with a consequent control strategy.

The use of beneficial insects should prevent the multiplication of the pests and has the best effect with a treatment of empty spaces and the subsequent application when the products are placed in stock.

The use of beneficial insects does not replace the hygiene measures neccessary on a regular basis and a control of the warehouse for pest infestation.

Warehouse stocks that have already been contaminated by pests cannot be "cleaned" neither by beneficial insects nor by chemical agents. If the use of insecticides is not possible and the infestation is still within reasonable limits, it can be reduced by the use of beneficial insects. It is always important to precisely record the current situation on site.

Therefore the golden rules for the prevention of damage by harmful insects are:

  • Prevention of infestation by a good and regular warehouse hygiene
  • Observation and early detection of the infestation by a pest monitoring
  • Use of appropriate control measures, like the use of beneficial insects



The control of food moths in the warehouse

Moths that damage stocks (Indian meal moths, Mediterranean flour moths or angoumois grain moths) are widely spread pests in food storage and processing companies. Endangered goods are cereal products, nuts, spices, teas, pasta, various sweets, like chocolate. But often also dry food for pets, especially bird seed and grain feed, is infested. The larvae can ideally develop here.

An infestation by food moths is not only unappetizing, but also hazardous to health because the feeding activity of the larvae spoils the food. The consumption of infested food can cause allergic reactions, mucous membrane irritations and bowel diseases. Besides, mites and various fungi settle on the fecal residues. Therefore, food infested by storage pests is only marketable to a limited extent and has to be disposed costly.

In the warehouse also the so-called `food moth`, the Indian meal moth Plodia interpunctella, is the most common one.

Appearance of the Indian meal moth (Plodia interpunctella):

The moths are very easy to recognize by the distinctive coloring of the wings (bronze bands on a silver background on the forewings), size about 1 to 1.5 cm. The larvae are yellowish-white and become up to 1.5 cm in size.

Way of life of the moths:

The female moths lay their eggs (200-300 eggs / female) on or in close proximity to food. Shortly thereafter the small larvae hatch and immediately start eating. Afterwards the larvae walk around and search for a suitable hiding place for pupation. At normal room temperatures, the larval development takes about 4 weeks. After another 10 days the next generation of moths hatches, lays eggs again and the cycle begins again.

In the warehouse the Mediterranean flour moth Ephestia kuehniella, the angoumois grain moth Sitotroga cerealella, the meal moth Pyralis farinalis, and different warehouse moths may also occasionally occur. The eggs of these moths are adopted by Trichogramma. For an effective control, however, the moth should be reliably determined, so that the application site can also be better defined.

To prevent further spread, a few simple basic rules should be observed. Main reason for moth infestation is the wrong and overlong storage of products.

  • Pests often get into the warehouse with the receipt of stock. On receipt of goods or at the latest before storage the batch should be checked for pest infestation (an infestation can be recognized by spun small droppings, cocoons or feeding damage on the packaging).
  • Apparently infested goods should be stored separately.
  • Paper and film packagings do not offer safe protection against pest infestation.
  • Regularly check the stock and do not store goods for overlong periods: the longer stocks are stored the higher is the risk of an infestation by pests.
  • Do not store goods openly, if possible fill them in tight-closing containers.
  • Always store stocks in a dry and, if possible, cool place.
  • Simple and smooth shelf structures offer only few hiding places to pests and are easier to clean.
  • Secure the windows with fly screens to prevent flying in from the neighborhood.
  • Pheromone traps only serve for control purposes and are no effective control agent. Only males are trapped, the females continue to lay eggs.
  • A fixed monitoring system, however, is the precondition for a successful pest management.
  • If all preventive measures do not solve the problem, parasitic wasps can be used against the food moths. The tiny parasitic wasps (smaller than 0.5 mm) are able to control the moths effectively, environmentally friendly, discretely and sustainably.

Application system TrichoKarte

The TrichoKarte is an application system for the Trichogramma parasitic wasps developed by us and tried and tested in the practice for many years. It is used a million times outdoors, in greenhouse growing, in stock-keeping and in private households

The TrichoKarte VORRAT is fitted standardly with 2000 parasitized eggs of Trichogramma evenasecens (for a release every 14 days) or 3000 parasitized eggs (for a release every 21 days). 3000 parasitized eggs occupy one surface.

We have been keeping these quality standards for 15 years. They are the basis for a successful control of the moths and the success of the procedure!

Biological control of moths in the warehouse

Trichogramma parasitic wasps are egg parasites, that is they look for the laid eggs of moths, lay their own eggs inside them and instead of a moth larva a new beneficial parasitic wasp hatches. This cycle repeats as long as there are moth eggs available. When the parasitic wasps do not find moth eggs anymore, they die.

To effectively break the development cycle of the moths, at least 4 releases of the parasitic wasps at 14 day intervals are necessary. Alternatively, in the warehouse the cards with 3000 eggs every 3 weeks may be used.

Depending on pre-infestation and risk situation, releases have to be made during the entire season (spring to fall).

The quality is decisive!

We have been breeding Trichogramma parasitic wasps for more than 20 years to biologically control different lepidopteran pests. The breeding and the provision of beneficial insects for a successful control requires a lot of experience and care. Our application systems, like the TrichoKarte, are permanently tested and have been established in practice for many years.

Especially for the use of beneficial insects a good consultation is important so that the beneficial insects can work successfully. We are happy to answer your questions about the use in the stock-keeping!

You can also purchase our TrichoKarte Vorrat with our distribution partners:



Biological control of moth larvae

The braconid wasp Bracon hebetor, also called Habrobracon hebetor, is one of the best studied parasitic wasps in the storage area. It paralyzes the free-living moth larvae by a sting, after that they immediately stop eating. In this way the parasitic wasp secures various larvae, makes them harmless and then starts laying eggs. The female Bracon lays its eggs on the outside of the moth larvae. The young wasp larvae feed on the moth larva of which only the dried up shell remains. Afterwards, the wasp larvae form mini silk cocoons from which a new generation of beneficial insects hatches.

The parasitic wasps orient themselves towards the smell of the moth larvae and their excrement. They are able to follow the pests into smallest gaps and cracks and even the hibernating larval stages in their cocoons are parasitized. Here, the braconid wasps turn out to be real trackers: they even bite through the cocoons of the moth larvae to reach them. From temperatures of 16°C upwards, the beneficial insects start laying eggs, we recommend a use as soon as in spring daily maximum temperatures of 20°C are reached. The optimum for the development of the parasitic wasps is between 25-30°C, for a short time also maximum temperatures of up to 35° are tolerated. The period of use is between the middle of April and the end of September.

The use is especially effective in bulk cereals or with cereal products. It is favourable to start treatment for the treatment of empty spaces after a thorough mechanical cleaning and when placing the grain into stock. If the pests have already established, beneficial insects can be used parallel to hygiene measures in "hotspots". In spite of a certain settling and reproduction, as long as moth larvae occur, Habrobracon hebetor should be released repeatedly in order to build up sufficient control pressure.

The following pests can be controlled by Habrobracon hebetor:

Mediterranean flour moth (Ephestia kuehniella)
Indian meal moth (Plodia interpunctella).
Warehouse moth (Ephestiae elutella)
Bee moth (Galleria mellonella)

The use of Habrobracon hebetor (against the larvae) can usually be combined with the use of the Trichogramma parasitic wasp (against the eggs). To determine the degree of infestation and the control success, pheromone traps should be used.

In grain warehouses and in processing companies, e.g. mills or bakeries, good control successes are achieved with it. Important for the determination of the degree of infestation and the ideal starting date is a monitoring or surveillance by using pheromone traps.

Application recommendation for preventive use:

The first treatment takes place immediately in the empty warehouse or directly after storage. Release interval: 14 days, temperature range 15-35°C. The quantities needed may vary depending on local circumstances.



Biological control of beetles that damage stocks by store chalcids

The store chalcids are naturally occurring antagonists of some important beetle larvae that damage stocks. Especially their ability to find larvae living hidden in the grain makes the parasitic wasps very interesting for the biological control.

The beetle larva is stung through the grain and is paralyzed. The parasitic wasp bores its ovipositor into the grain and lays an egg next to the beetle larva. The larva of the parasitic wasp hatches and feeds on the beetle larva during its growth and thus makes it harmless. After the pupation, the adult store chalcid gnaws a hole into the grain and leaves it looking for further pests. At about 26 °C (70% humidity) the development takes about 3 weeks, whereby the females live approximately for two weeks after hatching.

A female Lariophagus is only 2-3 mm in size. These beneficial insects are black and shimmer slightly metallic.

The following beetle species are parasitized:

Australian spider beetle
Flour beetle
Pea beetle
Lesser grain borer
Bean beetle
Grain weevil
White-marked spider beetle
Golden spider beetle
Shiny spider beetle
Rice weevil
Tobacco beetle

Additionally to the use of Trichogramma, the store chalcids can also be used against the larvae of the angoumois grain moth (Sitotroga cerealella) that unlike other moth larvae develop inside the grains.

Application recommendation LarioTop® :

Treatment of empty rooms for preventive use: 1 unit per 25-100 qm, temperature from 15-20 °C. Repetition after 14 days

In the grain warehouse: 1 unit per 25 qm, at temperatures from 15-20 °C.

The first treatment takes place immediately before or after placing the grain into stock. Repetition after 14 days.

Control of the sawtoothed grain beetles

The parasitic wasp Cephalonomia tarsalis is specialized in sawtoothed grain beetles and can localize the beetle larvae for several meters due to the small droppings. It is about 2-3 mm in size and black. When stung by the parasitic wasp, the beetle larvae are immediately paralyzed. Per beetle larva up to two parasitic wasps develop. After about 3 weeks, new wasps hatch from the cocoons.

As the sawtoothed grain beetle often appears after an infestation with wheat weevil, Cephalonomia tarsalis and store chalcids can be released together.
At the moment, two other beneficial insects are tested for the biological control of important pests: the parasitic wasp Holepyris sylvanidis against the mill pest confused flour beetle (Tribolium confusum) and the pirate bug (Xylocoris flavipes) against the material pest khapra beetle (Trogoderma granarium).



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.



Monitor, identify and control pests!

A first important step for a successful control of pests in the stock-keeping is the installation of a monitoring, a control system, to get an overview of the current state of pests.

By means of specific pheromone traps that bear the attractant of virgin female pests, it can be reliably determined if moths or beetles are being active. With the pheromone trap, for example, no female moths are caught and only a part of the male moths. If male moths are caught, then the egg laying females are also around: then Trichogramma parasitic wasps can be used for biological control.

Important: Distinguish the moths species with pheromone traps!

The pheromones for the different kinds of food moths (Indian meal moth, Mediterranean flour moth, warehouse moth) differ from the ones for the moths that damage textiles (clothes moth, case-bearing clothes moth). If they stick on a trap for food moths there is an infestation in the kitchen or in the storeroom, as food moths do not eat textiles and clothes moths in turn do not eat ceral products.

Pheromone traps: easy to use and nontoxic!

For the use in the warehouse reusable funnel traps or bucket traps are suitable. Here the pheromones have to be replaced regularly. Per room (up to 200 qm) one trap is sufficient. If too many traps are hung up they impede each other and the male moths loose orientation.  Places in which moths have already been observed are especially suitable as locations for traps. The traps should not be hidden from the moths. Of course, in a shop with customers one will make sure that the traps are not placed too noticeable.

Control and document the catches of the traps!

From spring onwards the trap should be controlled regularly and the catches should be documented in writing. This is the only way to get an overview over the current pests occurrence and to react in time if there is a risk and take control measures. Also after the control, the monitoring should continue.

Combinable with the use of parasitic wasps

The pheromone traps last up to half a year but should be replaced, especially during the warm months, after  three months in order to obtain a reliable catching effect. The attractants for moths are completely nontoxic and are also of no interest for the Trichogramma parasitic wasps.

Pheromone traps bought ahead should be stored in a cool place, e.g. in the fridge or in the cellar, so that the attractant does not vanish prematurely.