Leafhoppers on Herbs
I work for a country club and every year I have a heavy infestation of leafhoppers on the herb garden that supplies herbs to the kitchen. I've been trying to do some research on how to prevent/treat them, but I'm not sure the best option since they're on an edible and apparently tricky to treat. At this point they're all adults and even harder to kill at this stage. I've tried spraying twice so far with pyrethrin in the mornings but I can't say it did much. I've read the best time to treat for them is late spring when they are nymphs. When is exactly is "late spring" for my area? (I plant most of my annual herbs around the second week of May.) And what should I treat with? Spinosad, neem oil? Is there anything I could do to treat in the fall after the bed is cleaned up? My other concern is getting to the under side of leaves since I use a hand-held, 2 gal. sprayer and some herbs would be hard to get underneath based on their general growth habit. Any suggestions on how to provide adequate coverage? Anything you can recommend would be a huge help!
We recommend that you cover the plants with floating row cover and do some succession planting next season. This will not be possible with woody herbs like thyme. You may also want to try growing in a greenhouse. Keep weeds down, especially perennial weeds that harbor leafhopper eggs. We do not recommend chemical controls. See our link on leafhoppers for more information http://extension.umd.edu/growit/insects/potato-leafhopper