The traps should be positioned within a two-foot zone above the plants. The presence of thrips does not mean that damage will result from their feeding. Even large numbers of thrips in traps do not necessarily indicate that control action is needed. Damage Thrips feeding can stunt growth and cause leaves to become stippled, papery, and distorted. On flowers, thrips can cause dead spots and blotches to appear.
Healthy plants can usually tolerate thrip damage.
Infestations reduce the aesthetic quality of landscapes but usually do not seriously harm or kill woody plants. If control is necessary, use an integrated program that incorporates good cultural practices, conservation of natural enemies, and the use of less-toxic insecticides. Maintain diverse vegetation to conserve natural enemies for biological control of thrips. Use aluminum foil mulches to disorient thrips and prevent them from finding suitable pupating sites. Cultural Control Options Use a strong water spray to knock thrips off leaves.