Knowledgebase
Hibiscus leaves are netted #873851
Asked June 19, 2024, 7:59 PM EDT
Hello!
Our one-year-old hibiscus plants began having netted leaves last August, and I treated them with Neem Oil, but to no avail. This spring when the leaves appeared, everything looked healthy and fine. Now, however, some of the leaves are getting holes and will be netted if this keeps up. What is the cause? We can't find any bugs eating the leaves, but perhaps they are somewhere? Or is it systemic and needs to be treated through the roots?
Please help me find a solution. We have 5 plants that are showing signs of this problem.
Thanks so much!
Kent County Michigan
Expert Response
Hello Gretchen,
I would say that you have chewing insects on your hibiscus and most likely the culprit it Japanese Beetles - which you should be able to see at some point.
You can use a pyrethrin-based insecticide to treat your hibiscus, which is generally low in toxicity to people but it very toxic to bees. Neem oil works best when applied when the problem first appears as it discourages the bugs from feeding on the plant, rather than kill them.
Your other options are to pick off the beetles by hand as they are very slow moving.
Japanese Beetle traps are effective but sadly encourage all the beetles in your neighbor to come to the party.
Diligence this year will help with next years beetle infestation. Milky Spore is product you can buy that kills the grubs in the soil (grubs hatch into Japanese bettles). It takes a year to get established but then will be effective for up to 10 years or more.
Otherwise, Beneficial Nematodes will also kill the grubs, but must be applied in the spring before they emerge.
https://www.uky.edu/AG/Entomology/treepestguide/hibiscus
Above is an article about the Japanese beetles.
Hope this helps
Kathleen
