Chemical Control of Leafhopper on Roses

Identification

• Leafhoppers are tiny, winged insects that are difficult to see with the naked eye. Adults are less than 1/10 of an inch long. The insects leave a white, stippled appearance on rose leaves. As insect numbers increase, they may leave black spots of excrement on the leaves. Leafhoppers may also spread diseases to roses.

Products

• Many pesticides are labeled to treat leafhoppers. Look for pesticides containing diazinon, disulfoton, endosulfan, imidacloprid, lambda-cyhalothrin, malathion, neem oil, permethtrin, phenothrin or pyrethrins. Some of these pesticides are available in systemic formulas, meaning the plants take the poison in. Systemic pesticides are often most effective against leafhoppers. Read package labels carefully to ensure the product is safe to use on roses.

Timing

• Spray plants in spring, at the first sign of damage. Once the nymphs reach the adult stage, pesticides are less effective. The second generation of leafhoppers usually appears in late summer. Spray again if you notice signs of infestation. Spray pesticides on a clear, windless day and follow all package directions carefully.

Considerations

• Early monitoring of the rose plant is critical to controlling leafhoppers. Keep rose plants healthy through proper care to minimize the risk of rose diseases, which may be spread by leafhoppers. Plant roses in full sun with enough space for air to circulate freely. Remove diseased canes promptly and pick up leaves and debris to reduce overwintering of diseases and insects.