Trichogramma achaeae ichneumon wasps

There are many different methods of biological pest control, but one of the most effective is the use of Trichogramma achaeae parasitic wasps

What does the Trichogramma achaeae look like? 

This tiny parasitic wasp is no larger than half a millimetre, barely detectable with the naked eye. Since they do have some camouflage colours, detecting these wasps in the crop is almost impossible. Because they are widely used as natural control agents in various types of ornamental and vegetable crops, they are now found all over the world.  

How does this parasitic wasp operate? 

Trichogramma achaeae is a small wasp that parasitises on the eggs of harmful insects. This makes it a highly effective biological control agent against a wide range of pests, including:

• clothing moths
• food moths 
• aphids
• various beetle species  

Not only does the trichogramma achaeae parasitic wasp help reduce crop damage caused by these pests, but it also has no harmful side effects.

How do Trichogramma achaeae proceed

Trichogramma achaeae is a small parasitic wasp that preys on caterpillars and moths. It is an effective biological control agent of many species of caterpillars and moths, including caterpillars that damage crops such as maize, cotton and vegetables. The Trichogramma achaeae can control caterpillars well with minimal risk to other crops. 

An adult parasitic wasp lays an egg inside the egg of a moth. If the size of the egg allows it, parasitic wasps even lay several eggs inside the eggs of moths.

Usually, the eggs hatch after a little over a week and the new parasitic wasps start looking for their next prey. As long as food is available, this process is repeated. As soon as food is no longer available, the parasitic wasps die out. 

How do you evict parasitic wasps? 

Depending on the weather, it is best to release parasitic wasps in the early morning or late evening. They are sensitive to a lot of UV radiation, so putting them out in full sunlight is not recommended. 

How many parasitic wasps per m2: (curative)  

• 5m2 = 700 parasitic wasps (eggs)  
• 10m2 = 1400 parasitic wasps (eggs) 
• 15m2 = 2100 parasitic wasps (eggs) 
• 20M2 = 2800 parasitic wasps (eggs) 
• etc. so always multiply by 700 parasitic wasps per 5m2 

How many parasitic wasps per m2: (preventive)  

• 5m2 = 300 parasitic wasps (eggs) 
• 10m2 = 600 parasitic wasps (eggs) 
• 15m2 = 900 parasitic wasps (eggs) 
• 20M2 = 1200 parasitic wasps (eggs) 
• etc. so always multiply by 300 parasitic wasps per 5m2 

Weather conditions  

In most cases, parasitic wasps come in packs of 2,000 eggs. So these are not live parasitic wasps, they hatch after over a week and then go to work defeating your pest, both indoors and in the garden/greenhouse. Make sure the temperature is at least 15 degrees Celsius, both at night and during the day. Of course, this is especially true for outdoor deployments. If the temperature is lower, the eggs will not hatch. Extremely high temperatures also work against the parasitic wasps, between 20 and 25 degrees is perfect for the Trichogramma achaeae. Finally, rain and strong winds can also adversely affect the release of parasitic wasps. If possible, try to take this into account during the release.  

When is the effect of parasitic wasps noticeable? 

Since we talk about eggs in the previous section, we build on that. Under ideal conditions, the eggs of parasitic wasps hatch after 7 days. From then on, they start hunting for moth eggs, for example. In these moth eggs, they lay their own eggs that hatch after about a week, causing the moth eggs to turn black and not hatch again. Usually the first effect should therefore be noticeable after two weeks, if sufficient food sources are present the Trichogramma achaeae reproduces itself. If this is not the case, they will slowly die out and so you will also be rid of your pest. Combining with pheromone traps or mothballs is not recommended as these can also attract and kill the parasitic wasps. Separately at intervals of at least 3 weeks is of course possible.