A key to living with western flower thrips is to keep populations low outside the greenhouse so that only a few are around to get onto the new crop. Grow a low-risk crop Vegetable crops vary in their susceptibility to western flower thrips. Tomatoes are a low-risk crop. They suffer little damage from the thrips but the thrips can transmit tomato spotted wilt virus. The risk from the virus is greatest in summer, so plant tomato crops in winter or spring.
Capsicums have a high risk from thrips damage and tomato spotted wilt virus.
Cucumbers are at risk from thrips damage to the plant and, unlike onion thrips, western flower thrips can damage cucumber fruitlets. Greenhouse beans are probably at risk from thrips damage. At present, insufficient information is available about the relative risk of flower crops. Pesticides Only a few pesticides give any practical control of western flower thrips and none are ideal for this type of insect. All the pesticides should be used sparingly because the pest is known to become resistant to pesticides very quickly.