Pest 411 Chilli thrips

by Alejandra Monterrosa and Shimat V. Joseph, Department of Entomology, University of Georgia

Fig. 1. Adult chilli thrips.

Andrew Derksen, USDA-APHIS

in the United States. This thrips first created economic problems in Asia, Australia, Africa and Oceania where they attack several crops such as strawberries, cotton, tea, citrus and chilies. They infest more than 150 crops. This pest has become increasingly problematic in nurseries because of its wide host range, small size, rapid reproduction and development. They have unique ability to quickly adapt in a new region. Chilli thrips was first noticed in the United States in Florida in 1991 but did not immediately establish. In 2005, this pest was observed on roses in Florida. This pest is also established in Hawaii and throughout the Caribbean Islands. In Georgia, chilli thrips was first reported in 2007.

Chilli thrips is small in size, about 2 mm in length. It has a pale-yellow body with a pair of darker wings. The antennae have eight segments with alternating patterns of dark and pale yellow.

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Chilli thrips lay eggs inside of plant tissue that is above the soil. The eggs hatch in about six-to-eight days in summer months. Newly hatched larvae go through two larval stages, which all together lasts about a week. During these two stages they feed on the new growth of the host plant. After completing larval stages they enter into a prepupal stage that lasts for about a day then they go through a pupal stage which lasts about three days. The pre-pupal and pupal stages are inactive stages thus the thrips do not feed on plants. Chilli thrips pupae are found in the cracks and crevices or leaf litter on the plant. They are rarely found on the potting soil media. Thereafter, they molt into adults. A female chilli thrips produces about 60 to 200 eggs in her lifetime. The life cycle can last from 14 to 20 days.

Prior to U.S. introduction, host range of chilli thrips was about 40 plant families. Now, chilli thrips are found on additional plant taxa. The main wild hosts are Acacia, Brownea, Mimosa and Saraca.

Chilli thrips are serious pests of different plants in different regions of the world. In Asia, chilli crops on the Indian subcontinent, tea and citrus in Japan, as well as sacred lotus in Thailand. Other major economic hosts include banana, cocoa, corn, cotton, grapes, kiwi, melon, peanut, pepper, strawberry, and roses. Recently added hosts are avocado, cashew nuts, canistel,

dragon fruit, miracle fruit, sapodilla, guava, litchi and mango. This shows that its host range is expanding as this pest is exposed to new plant species in new region.

Monitoring for the early incidence of chilli thrips on the plants is the key.

Chilli thrips are attracted to yellow or blue sticky traps (Fig. 2). The sticky traps should be monitored and replaced every 7 to 10 days. Beating the plant branches to white paper or fabric would also help to determine if there is an active population of chilli thrips.

Once thrips are found, it is critical to identify the thrips because there are other species of thrips found on the same types of plants such as western flower thrips or greenhouse thrips. Removal of weeds around infested plants can help lower population size of thrips.

Biological control is one effective way to reduce chilli thrips population such as the minute pirate bug, Orius laevigatus, as well as the lady bird beetles. There are also several mite species such as Amblyseius degenerans, Amblyseius cucumeris Shimat Joseph and Amblyseius swirskii Fig. 2. Chilli thrips are attracted to yellow or as well as nematode, blue sticky traps. Steinernema feltiae, that are effective in reducing chilli thrips population on plants. Another way to control them is through the use of insecticides. Imidacloprid, thiamethoxam, triazophos, acetamiprid, acephate, thiacloprid and bifenthrin can reduce thrips population. Mid Tenn Turf, Inc. — 1/2 Page Horizontal Ad for Deep South Turf Expo Program