Basil being devoured by invisible pest (not aphids!) - Ask Extension
Three otherwise healthy basil plants are being eaten up: the bites are in the middle of the leaf AND from the outside (see photos). There are black sp...
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Basil being devoured by invisible pest (not aphids!) #874543
Asked June 24, 2024, 9:51 PM EDT
Three otherwise healthy basil plants are being eaten up: the bites are in the middle of the leaf AND from the outside (see photos). There are black specks like eggs or feces on the top of the leaves. No caterpillars, like you find with cabbage moth caterpillars, and the holes aren't the circles — they seem more chomped in a jagged way. I've searched for earwigs and set traps — didn't catch anything. I've checked at night and early in the morning. I haven't seen tiny aphids or flies. No pest seems to be living under the pots, or hovering at the base. I am afraid to use neem oil. The only clue are these black dots (which come off when you rub them). What is this pest and what can control it?!
Livingston County Michigan
Expert Response
The black specks are insect frass (poop), and the holes are chewing insect damage. Several types of insects are active feeders at night. This includes slugs, flea beetles, and Asiatic Garden beetle. It is most likely Asiatic Garden beetle or another beetle species, since they would create the large feeding damage and are active in high numbers now.
Unfortunately, there isn't much that can be done to deter them. I would advise against most chemicals on the basil. Neem oil is a lower toxicity product that could be applied before evening to reduce the impact. Covering the plants underneath a mesh or fine netting would also prevent larger beetles from reaching the leaves.
Unfortunately, there isn't much that can be done to deter them. I would advise against most chemicals on the basil. Neem oil is a lower toxicity product that could be applied before evening to reduce the impact. Covering the plants underneath a mesh or fine netting would also prevent larger beetles from reaching the leaves.
Thank you! All three plants are indoors. Would bringing them inside at night until the beetles subside be a solution? Or do they beetles live in the soil in the pot?
I have row cover that lets in 90% light: would that stop the beetles also? If they are outside the pot I can’t see how any could penetrate.
The beetles started suddenly; are they here to stay all summer long or is there a period — three weeks or something— after which they move on?
Thank you!
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The beetles are active for the next few weeks. Bringing them at night would address the issue if it's a nocturnal pest.
The row cover is an easier solution. THat will reduce the chances of Asiatic garden beetle or another large insect from entering, though there is still a chance they could find the leaves.
The row cover is an easier solution. THat will reduce the chances of Asiatic garden beetle or another large insect from entering, though there is still a chance they could find the leaves.
