I’ve read a long list of things Trichogramma wasps are effective against and a few army worms were listed but I didn’t see the yellow striped one there. It’s possible they are effective but weren’t on the list. Does anyone know?
Also, since you need to put the wasps out every 3 weeks or so do you have to order them every three weeks or can you order a bunch at once and save them for a few months to release a few at a time?
Hi Robert –
There are a couple promising avenues to take to control yellow-striped armyworms. Before applying some absurdly toxic chemical into your garden that would likely kill everything, including beneficial insects, a natural remedy should always be your first move.
Armyworms are prey for a number of parasitic wasps and flies. Trichogramma wasps help in controlling and decreasing the army worm population, if applied at the proper times. It is better to try to control them early rather than later.
The worms overwinter in their pupal stage, emerging as adults when the ground thaws out in March-May. When these adults emerge from the soil in the spring, they set out to mate and lay more eggs. The best time for making releases is when the armyworm eggs are present.
Since yellowstriped armyworms have multiple generations in a single growing season (about 40 days from egg to adult, 3-4 generations in a season), multiple applications may be necessary. We do NOT recommend storing trichogramm for more than a couple of days.
Monitoring the moths emergence in the spring with sticky traps, paying attention to the grey/white moths hovering around your lights at night as well as checking the plant surfaces (under leaves too) can give you an idea about how bad the infestation is. If the armyworm population seems to be getting out of control, a Bacillus thuringiensis (Bt) application might be necessary.
Here is a link to our page concerning armyworms and our products to control them: https://www.planetnatural.com/pest-problem-solver/garden-pests/armyworm-control/