Leaf Hopper control throughout the season - Ask Extension
Hi, I had a problem with Leaf Hoppers on my grapes last year. I would like to start some control in the Spring but also understand how to control if I...
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Leaf Hopper control throughout the season #891759
Asked January 20, 2025, 5:13 PM EST
Hi, I had a problem with Leaf Hoppers on my grapes last year. I would like to start some control in the Spring but also understand how to control if I see mature insects during the growing season. Can you recommend an insecticidal soap with application instructions for Spring and then other options for mature Leaf Hopper control
Umatilla County Oregon
Expert Response
Hello, thanks for your question. This guide from UC Davis has a lot of good info to get you started:
https://ipm.ucanr.edu/agriculture/grape/leafhoppers/#gsc.tab=0
In particular, the part about threshold sampling for nymphs will be helpful. Keep in mind that insecticidal soap will not be the most effective way to control leafhopper. Insecticidal soap works through smothering- it must make contact with, and envelop, the insect to be effective. insecticidal soap has no preventative value, it can be hard to get the soap on the undersides of leaves where the insects are hiding, and it can stain the grapes if used once fruit has set. This is why insecticidal soap is almost last in the listing for treatment options.
There are a lot of beneficial insects that will feed on, or parasitize, the nymphs- in some years treatment will not be necessary if the beneficial insects are present in sufficient numbers.
The above linked page also contains pesticide options for adults. Several of these are systemic pesticides, and thus will ahve limitations on when they should be applied to the vines.
I hope you find this helpful, Nicole
https://ipm.ucanr.edu/agriculture/grape/leafhoppers/#gsc.tab=0
In particular, the part about threshold sampling for nymphs will be helpful. Keep in mind that insecticidal soap will not be the most effective way to control leafhopper. Insecticidal soap works through smothering- it must make contact with, and envelop, the insect to be effective. insecticidal soap has no preventative value, it can be hard to get the soap on the undersides of leaves where the insects are hiding, and it can stain the grapes if used once fruit has set. This is why insecticidal soap is almost last in the listing for treatment options.
There are a lot of beneficial insects that will feed on, or parasitize, the nymphs- in some years treatment will not be necessary if the beneficial insects are present in sufficient numbers.
The above linked page also contains pesticide options for adults. Several of these are systemic pesticides, and thus will ahve limitations on when they should be applied to the vines.
I hope you find this helpful, Nicole
