This is certainly not a complaint, but I've never seen this before. My tomato hornworms seems to be getting sick and dying off before I can find them and pluck them off. No, they do not have those wasp eggs on them. Rather, their head and thorax starts to turn brown/black and then they shrivel up and die, either starving or dehydration. Any idea what would cause this? I have used no pesticides on any of my 4 acre property, and I'm surrounded by virgin desert.
I would guess you are lucky and there is a zoonotic pandemic in your area wiping them out. While besides wasps, parasitic flies plague hornworms, they usually liquify in a pool of maggots. I suspect you have a virus, fungal or bacterial infection.
My next thought Powell was any issues for people. It might be find to have bugs die but why is an important question because of the close interconnection of our gardens to our tables :-)
I found one possible culprit, and does not "appear" to have any issues for people or animals, but I'm not sure this is 'the' culprit. Thoughts Powell?
WOW, and Wow - I looked at Powell's supplied link and found further discussion of possible infections to caterpillars - the article is mostly about Monarchs but is related. May take a while to load.
And thank you for posting Jeanne - it is at the very least an interesting occurrence to look for.
There is a fruit orchard about 1.5miles away from me, to the SW. I wondered if they might have used something on their crop that could have wafted over this far? Maybe I should go over to chat.
Jeanne, that would be a good idea. The info on the Baculovirus included lots of discussion on its use "against" larvae.
If they are 1.5 miles away and critters are dying in your gardens I would want to know that!
I doubt it. Anyone paying for spraying would be pissed if spray that they were paying for was landing 1.5 miles away instead of in their orchard.
Anything being sprayed on an orchard would likely be fairly broad spectrum to kill caterpillars. I would assume a crop duster would have had to fly overhead with a valve open but even then I don't think they would be so low as to be that effective.
Baculovirus was at the top of my list and they are extremely specific for their host. I definitely would leave the carcasses in your garden to break down. From Catherine's link how the corpse rots is a clue as to the mode of transmission and the pathogen type responsible.
Powell good thought on observing how the critter rots to determine mode/origin. Icky but it would be informative.
Powell, this is a really small scale orchard, Fenway Orchard, that grows primarily apples and peaches. No crop dusting there, likely not more than some poor guy slogging along with a backpack sprayer.