Corn ear worms… what do you do for control?
Our KSU Extension says:
There is a three-week period from silking to harvest, but there is only a two-week period from when the silks appear to when they begin to dry. Since moths prefer juicy silks and shun those that have started to dry, insecticides are only needed the first two weeks of silking. Homeowners can use cyfluthrin (Baythroid; BioAdvanced Vegetable and Garden Insect Killer) or spinosad (Captain Jack’s Dead Bug Brew; Natural Guard Spinosad, Monterey Garden Insect Spray). Spinosad is an organic product.
Sorry there wasn’t a bulletin number, or I would have sited it.
It would be pretty hard to go through the rows spraying the silks on each ear of corn. I have 7 rows, 25’ long. The rows are spaced at 3’, but not much room to maneuver in there now.
Is it worth it? I am thinking I should do it, but I doubt I can get 5 sprays on in 2+ weeks.
I got my Indian corn sprayed only once and shouldn’t have bothered. I found multiple worms per ear when I checked them yesterday.
Just wondering what the majority of folks here do and what (if anything) works well.
Thanks!
Ive had good luck spraying bt or spinosad on the silks a few times starting when about half the stalks have silks. Ive sprayed once or twice a week for a couple of weeks. Earworm pressure here is BAD from may onward. Ive sprayed five 33 ft rows spaced 2 ft apart. It was a little tedious but doable.
Thanks @barry. I planted my sweet corn late, so it was just starting to Silk this week. I think I have time tonight or tomorrow so I am gonna try anyway. I should be able to manage 2 sprays/week. I blew off the Indian corn - Only sprayed once. Bad call on my part. I will know better for next year.
Full disclosure…i got lazy on the current batch which is a week from harvest. I sprayed once with spinosad when half of plants had silks. Then after a week i sprayed bt. That was a few days ago. I just did a random check of 10 ears on different plants. 50% had a worm! So stick with twice a week for sure. Last year at this time i was very consistent with twice per week and had no damage.
Ok so I checked the ears when I was out this evening. They have matured a lot since Monday/Tuesday! I opened some of the more mature ears and found dark spots on the kernels near the top- so I think this is probably sign of very small worms already at work.
So now what? Spraying the silks won’t do any good if the eggs have hatched and worms have migrated in to the ear, right? I can still spray in hopes of saving any that haven’t had worms hatch already, but the rest are too late to save?
Not sure if spraying now will help. For me, the worms usually eat around the tip so i just cut that off and eat up. But its not ideal and there is some loss for sure. The best thing would be spray half of it and see if there is any difference. Then at least youll know for the future if a late spray can help. I have seen them out and about nibbling on the silks at a large size so maybe they make trips back up the silks in range of an insecticide from time to time.
Thanks @Hillbillyhort. I tried oil one year and it didn’t work for me. I don’t know if it was timing or technique, but I haven’t tried it since. Maybe I should reconsider that approach.
I guess having worm damage would be the norm, I just wanted to see if I could actually grow some nice clean ears damage free.
I am growing some Painted Mt for ornamental purposes this year. Every ear is damaged. I definitely want to be able to grow this worm-free next year!