- Thrips are very difficult to control with pesticide alone because of their life cycles. University of California experts recommend leaving small thrip infestations alone. Intervention may be warranted when significant damage occurs to food-producing or greenhouse plants. Often, a small thrip infestation will not be obvious until after the insects have moved on, so be certain that your plants are infested before treating. Thrips can be caught using yellow sticky traps or observed by shaking affected branches over white paper or sheets to catch insects and larva.
- Several pesticides can be effective against thrips, when applied at the correct time. Narrow-range oil, azadirachtin, neem and pyrethrins combined with piperonyl should be applied to plants when damage first appears, if insects are still present. Repeat application every five to 10 days because these chemicals are only effective against newly hatched thrips and young adults. Greenhouse thrips can be controlled with any broad-range pesticide because they feed and develop in the open. Spinosad is showing promise in the battle against thrips. Because it is derived from bacteria, it is less harmful to insect predators.
- Predatory insects lead the battle against thrips. Many insects feed on thrips, though little research has been done on released colonies of predators. Encouraging predator populations by limiting insect poisons and controlling dust. Predators that feed on thrips include green lacewings, minute pirate bugs, parasitic wasps and predatory mites.
- Thrips are often attracted to grassy areas when they begin to dry in late spring or early summer. Controlling weeds is vital to keeping thrip populations at bay. Other cultural controls include pruning away heavily infested plants, using row covers over susceptible young plants and using reflective mulches, which often confuse flying insects.
Thrips and Pesticides
Pesticides for Thrips
Thrip Predators
Cultural Controls
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