Thrips

by Wizzie Brown

Thrips are very small plant-feeding insects. Adults are elongate and slender with fringed wings. Immatures look similar, but are smaller in size and lack wings. Color can vary from pale yellow to dark brown-black.

Thrips feed by puncturing plant tissue and sucking out juices, leading to discoloration, stippling, or silvering of the leaf surface. Feeding can cause stunted growth and premature leaf drop. When thrips feed on fruit or flowers, damage causes a brown discoloration of the surface and may give a distorted appearance to the fruit or flower. Thrips are also capable of transmitting various viruses.

Not all thrips are detrimental to plants. Some species feed on fungal spores or pollen, while others are predators and feed on other insects and mites. Some types of thrips may occur on a wide variety of plants, but only cause damage to a certain few.

Management of thrips should use an integrated program incorporating cultural practices, natural enemies, and less-toxic insecticides. Monitoring for thrips can either be done by shaking a branch over a white piece of paper and looking for dashed lines on the paper, or by clipping buds or other suspected plant parts and placing them into a jar of 70% alcohol and shaking to dislodge any thrips. Yellow sticky cards can also be utilized for monitoring.

Thrips can move into landscapes from adjacent weedy areas. When possible, keep nearby weeds in check. Keep plants healthy by planting native or adapted plants in the correct location in the landscape, watering and fertilizing properly, and pruning correctly. Reflective mulch can be utilized to disrupt thrips’ ability to seek out host plants. If you choose to use a pesticide for thrips control, look for less toxic ingredients such as insecticidal soaps, azadirachtin (neem), horticultural oils (use when under 85 degrees outside), spinosad or pyrethrins.

For more information or help with identification, contact Wizzie Brown, Texas A&M AgriLife Extension Service Program Specialist at 512.854.9600. Check out my blog at www.urban-ipm.blogspot.com

This work is supported by Crops Protection and Pest Management Competitive Grants Program [grant no. 2017-70006-27188 /project accession no. 1013905] from the USDA National Institute of Food and Agriculture