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New Invader: Chili Thrips, Scirtothrips dorsalis Hood

Picture of adult chili thrips.
Photo credit: Dr. Lance Osborne, University of Florida
http://mrec.ifas.ufl.edu/lso/thripslinks.htm 

Just as a bowl of chili will warm your body, chili thrips will also make you “heated,” if they are found in the landscape. This thrips is commonly found in such areas as South Africa, Pakistan, India, Bangladesh, Sri Lanka, Thailand, Malaya, Indonesia, New Guinea, Solomon Islands, Australia, Taiwan, Japan, Hawaii, and Venezuela. It is also commonly found in the Caribbean. However, they were spotted in south Texas within vegetable transplants this year. Therefore, it will only be a matter of time before they are seen in North Texas. Adult chili thrips have a pale body with dark colored wings and are less than 2 mm in length. The immature thrips are pale in color. Their lifecycle can be completed in 14-18 days, with the adults living about 11 days. Chili thrips have a wide host range including many crops. They can be found on over 100 host plants, including beans, chrysanthemums, citrus, corn, cotton, eggplant, grapes, onions, peanuts, pepper, roses and tomatoes. They attack the terminal growing points of plants, mainly feeding on young leaves, buds and fruits. This surface feeding usually appears shiny silver at first and then becomes yellow to greenish-brown in color. Dry conditions can cause population increases, and feeding damage appears more quickly when plants are water stressed. Chili thrips are also capable of spreading tomato spotted wilt virus, peanut necrosis virus (PBNV), peanut chlorotic fan virus (PCFV) and tobacco streak virus. If large populations exist, total defoliation and potentially heavy crop loss can occur.

Some Control Tactics:

Non-Chemical Control Options: Inspect plant materials to prevent infestations. Preserve natural enemies, which include minute pirate bug, green lacewings, parasitic wasps, predatory mites and nematodes (Thripinema spp.).

Some Chemical Control Options:

Monitor for thrips and treat at first sign of damage. The use of foliar insecticides is more effective at controlling this thrips, since they are usually feeding on exposed plant surfaces. Some foliar sprays can include such chemicals as azadirachtin, spinosad, novaluron, bifenthrin, permethrin. Systemic insecticides will also provide control, such as those containing imidacloprid.


Noticing Early Populations of Spider Mites Will Help with Control Measures


Two-spotted spider mites, Tetranychus urticae Koch.
Photo by: University of Florida

The two-spotted spider mite is a common pest of many landscape and nursery plants. Adult two-spotted spider mites are small, arachnids with dark spots on each side of their bodies. They feed on the phloem on the underside of foliage, causing a speckled appearance. They will construct a web where all the life stages develop and are well protected. The plant nutrients allow these mites to multiply rapidly. If large numbers of mites are feeding, the foliage will turn yellow and the leaves will drop. Heavy infestations can even cause death to the plant. New generations will continue to develop until cool weather occurs, leading to a reduction of activity.

Some Control Options:

Non-Chemical Controls:

There are many predators of the two-spotted spider mite that can be introduced or conserved, such as the minute pirate bug, big-eyed bug, green lacewing, and a variety of predatory mites such as Galendromus occidentalis, Phytoseiulus persimilis, and Neoseiulus californicus. Some predatory mites require high humidity levels, so are more effective indoors.

Chemical Controls:

Some options include dormant oils for use in the fall to early spring to kill eggs and dormant adults. Some other options include insecticidal soap, bifenthrin, cypermethrin, or a combination of imidacloprid and bifenthrin. A thorough, repeat application of insecticides to the underside of the foliage is needed to gain control.  

Mention of commercial products is for educational purposes only and does not represent endorsement by Texas Cooperative Extension or The Texas A&M University System. Insecticide label registrations are subject to change, and changes may have occurred since this publication was printed. The pesticide user is always responsible for applying products in accordance with label directions. Always read and carefully follow the instructions on the container label.


 
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