Tomato thrips

Tomato thrips originate from South America and are widespread throughout Australia. They prefer to feed on flowers and have a wide range of hosts including tomatoes, tobacco, capsicums, lettuces, potatoes, grain legumes and several weed species. They are known vectors for tomato spotted wilt virus (TSWV) which can cause considerable yield losses in tomato, capsicum, potato and lettuce crops.

Description

Most prevalent in mid to late summer, tomato thrips range from dark brown to black, with clear wings and dark legs. They are slender and just visible to the eye (1.0-1.7 mm). Females lay eggs into flowers, leaves or fruit and the larvae hatch a few days later. Tomato thrips larvae are paler than adult thrips and are wingless. Early in the season thrips larvae are predominantly male but once numbers increase, females dominate the population.

While tomato thrips often reside in flowers, the sucking damage caused by both the larvae and adults produces deformed flowers, leaves, stems and fruit. In addition, shoots, fruit and leaves can develop a silvery appearance.

Control

As some thrips such as western flower thrips and onion thrips can develop resistance quickly, it is important not to rely on insecticides alone. Natural predators of thrips include pirate bugs, lacewing larvae and ladybird beetles, therefore encouraging these populations will assist in keeping thrips populations low. Avoiding applications of broad spectrum, residual chemicals is important in maintaining these beneficial insect populations.

Regularly monitoring plants for evidence of thrips damage, managing host weeds and planting resistant or tolerant crop varieties will assist in reducing economic losses. Also, turning in harvested residues in crops such as green beans, may assist in killing any thrips that may be present pupating in the soil.

Thrips often occupy protected areas such as flowers, growing tips and leaf curl galls. Consequently, systemic pesticides can be more reliable for control compared to contact pesticides which only control thrips present on the plant surface.

Movento® is ideal for controlling sucking pests which hide in protected parts of the plant and is also soft on most beneficial species when used as directed. Movento is registered for control of western flower thrips in beans (green), celery, rhubarb, eggplants, peppers, tomatoes, herbs, bulb vegetables (excluding bulb onions) and lettuces. It is also registered for control of tomato thrips in beans (green), celery, rhubarb, bulb vegetables (excluding bulb onions), and herbs. Registration for control of plague thrips exist in celery, rhubarb, herbs and provides suppression only in grapes. It is also registered for Kelly’s citrus thrips in citrus and for onion thrips in bulb onions and bulb vegetables. Lastly, it is also registered for suppression of northern plague thrips in grapes.

Movento® Energy is registered in bananas for the control of banana rust thrips.

References

Broughton, S, Jones, R and Coutts, B (2004) ‘Management of thrips and tomato spotted wilted virus’, Department of Agriculture WA, Farmnote 69/2004, https://ausveg.com.au/app/data/technical-insights/docs/fn069_2004.pdf

Steiner, M (Viewed Oct 2019) ‘Which thrips is that? A guide to key species transmitting Tomato Spotted Wilt Virus in NSW’, NSW Department of Primary Industries, https://www.dpi.nsw.gov.au/__data/assets/pdf_file/0006/177324/tswv-transmitting-thrips.pdf