Pickleworms go after a number of crops. Cucumbers. Squashes, both summer and winter types. Pumpkin. Watermelon. Gourds. Melons in general. USDA reports indicate that the moth prefers some crops over others, but here on my farm, the moths are non-discriminating. They go for them all about the same.
The adult moths are your standard little night moths. They hide during the day.
I've found the little pickleworm maggots inside squash blossoms, destroying the interior. They leave a round little hole in an unopened flower.
(Photo by John Capinera, U of Florida)
But mostly they enter young fruits. Often very young fruits abort because they are damaged so quickly. But others continue to grow. If attacked late, the fruits will actually grow large enough to harvest. If there isn't a lot of damage, I can cut away the ruined spots and use the rest of the veggie to eat. The pickleworm infestation doesn't ruin the eating quality of the undamaged areas.
How can I tell I've got pickleworm? Easy. Look for their holes. On flowers sometimes. Mostly on the fruits themselves. And if I see a tiny yellowed aborted fruit, I now know that it's pickleworm. While I was learning, I use to break the fruits open and I'd find a small maggot. Aha, busted! Pickleworm!
There's the little maggot. Can't see it? Here it is again where I moved it for better viewing.....
This little guy is in it's final instar stage. It's ready to pupate and become a moth. Younger instar stages have rows of little spots running down their bodies. At first I thought I had two different pests, but then I read that the last instar stage loses its spots.
How to control pickleworms? I can opt to do a couple of things.
.....grow parthenocarpic cucumbers in a screen cage. The screen keeps the moths out. And parthenocarpic means that it doesn't need to be pollinated.
.....cover the crop with screen, reemay cloth, or even plain sheets during the night and remove them during the day. This keeps moths out at night and allows bee access during the day for pollination purposes.
.....grow the crops in a screen cage and hand pollinate
.....bag each female flower and hand pollinate. If too many male flowers are being destroyed, then bag some of them too for a source of pollen.
.....spray flowers inside and out with dipel frequently and after each rain. That is hard to do during wet years, but much easier during drought years. It is a daily job because new flowers are always emerging.
.....set out moth traps. Homemade moth traps help, but they also catch plenty of other night insects, some of which are beneficial.
I've found that growing pickle type cucumbers is better. Less pickleworm damage even if I do nothing. And growing the crops in tall grass helps. Guess the moth has a harder time finding and getting to the flowers and fruits. I've managed to harvest pumpkins by simply letting the vines run through tall grass. Of course it's a bear to find the blasted pumpkins, so I have just as hard a time as the moths!