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Photo: Dr. Arnold H. Hara, CTAHR
Leaves on affected plants look like lace, or like they’ve been peppered with buckshot. Some of the leaves may have nothing left but the veins.
The Chinese Rose Beetle feeds at night and attacks over 250 plants, everything from ornamental trees to leafy vegetables. The adult rose beetle is reddish brown and about ½ inch long. Rose beetles come out at dusk and feed for a couple of hours before retreating to the leafy hummus at the base of nearby plants.
Chinese Rose Beetles are attracted to dim light and repelled by bright light. You could use this to your advantage by shining bright lights on prized plants for 2-3 hours after dusk, the rose beetle prime feeding time.
Some people have had success with rose beetle traps. This is likely to work better for the home gardener than for the farmer. You may have better luck going out after dusk with a flashlight and hand picking rose beetles every few weeks. Drop them into soapy water.
Another approach is to build a protective barrier around young plants using a wire cage lined with shade cloth. This will protect the plant until it is large enough to survive rose beetle attacks.
See an Extension agent for pesticide recommendations.
Some gardeners have had some success with the rose beetle trap. If you have a large infestation of rose beetles, this is not likely to work well, nor does this work in large spaces (farm).
You will need:
Put the rose beetle trap in the garden near the plants you want to protect. Fill the bowl with water and add a few drops of dishwashing soap. Rose beetles will be attracted to the light and will drop into the water. The soap prevents them from recovering.
Kendal Lyon, Hawaii Island Master Gardeners