Photos and article by OCRS Master Rosarian Kathy Monge
Chilli Thrips have arrived in Southern California. These insects are too small to see but do far greater damage to your roses than traditional thrips. These insects are poor flyers but are easily carried by the wind. Many rose gardeners have this pest in their gardens. Be on the lookout for the following signs, all included in the images at the bottom of the page:
1) Puckered, small rose leaves on new growth.
2) Short stems
3) Brown buds and/or malformed flowers
To combat this insect, start with cutting all affected plant growth off. This cut should be done on the cane below this affected cane. Throw this material out immediately. Do not use this in a compost pile. Clean your pruners to kill any insect material.
The eggs of the thrips are located in the soil. Using personal protective gear for your safety, spray Neem Oil or a spinosad solution on the ground, concentrating underneath the plant. Always follow the recommended amount per gallon. More does not mean better. Repeat in one week. The life cycle will vary from 5 days in above 90 degree weather to 14 days in cooler weather. You will probably need to maintain a 2 week schedule for spraying. Frost/very cold weather will kill the eggs, but that is not necessarily good news for our Zone 10 climate.
Be diligent to prune off new thrip damage. You also can find additional information by clicking here. This link will take you to an article titled, "Pictoral Guide to Identifying and Treating Chili Thrips."