Wasps versus Worms
I have a Catalpa Tree that I planted specifically for the Catalpa worms. However when the worms appeared this year they were covered with wasp parasites. How do I get rid of the wasps without harming the Catalpa worms
I couldn't think of a way to avoid killing both so I proposed this question to Lee Townsend, UK Extension Entomologist. This is what he proposed:
That is a tough one and I am not sure there is an answer for it. Keeping wasps away from the worms is the best alternative I can think of. If practical, a person could collect the worms and foliage and rear them in screened or protected areas so the wasps couldn’t get to them. Just add foliage as needed and remove worms that develop cocoons. The wasps fly around looking for the caterpillars so keep them out of reach of them.
Another possibility is to collect the worms from the trees when they about 2/3 grown and keep them cool so the wasp cocoons don’t develop. I’m not sure of a temperature but would try 45F to 50 F. The worms would be a little smaller than full grown but you wouldn’t need to go thru the feeding part.Hope this gives you some ideas. No insecticide will do what you want it to do unfortunately.