Vegetables

Adult thrips. Dr. David Kerns, Professor, IPM Coordinator and Extension Specialist, Texas A&M AgriLife Extension, College Station

Article author: Kerry Siders
Most recently reviewed by: Suhas Vyavhare & Pat Porter (2020)

Common Name(s): Thrips

Description

Thrips are slender, cigar-shaped, straw-colored insects about 1/15-inch-long as an adult. They have piercing and sucking, cone-shaped mouthparts. Adults have narrow wings fringed with hairs and can drift long distances in the wind. Due to their small size, thrips are often difficult to see.

Habitat & Hosts

Onion thrips have an extremely wide host range. They feed and can reproduce on several cultivated crops including onion, cotton, beans, fruits, vegetables, and practically all small grains. Citrus thrips feed on leaves and fruit of most all species of citrus tree plants. Greenhouse thrips feed on a wide range of horticulture plants. Gladiolus thrips feed on gladiolus and other species of flowers. Western flower thrips feed on a wide variety of plants including chrysanthemums, gloxinia, impatiens, tomato, cotton, vegetables, and grasses. Some plants species, varieties and cultivars are more attractive to the thrips than others.

Life Cycle

In the thrips life cycle, egg-to-adult development takes about 16 days. Eggs inserted into the plant tissue by the female’s sharp egg-laying tube (ovipositor) hatch in about 6 days. Two larval stages require about 6 days for completion; then, the prepupal and pupal stages take an additional 4 days and generally occur in the soil. The average life span of a mated female is about 35 days, and each female can produce fifty or more eggs. Thrips can reproduce without mating. Mated females produce both males and females; unmated females produce only males.

: Western flower thrips, Frankliniella occidentalis. Image by David Cappaert, Bugwood.org

: Flower thrips, Frankliniella sp.. Image by Bruce Watt, University of Maine, Bugwood.org.

Management

If you live in the State of Texas, contact your local county agent or entomologist for management information. If you live outside of Texas, contact your local extension for management options.

Thrips management needs and strategies vary across commodities. Avoid planting cotton during cool conditions so that young plants will not be affected when plants are most susceptible to thrips damage. Not planting cotton near small grains and onions or adjusting planting date helps alleviate thrips migration into the field. Chemical control is an effective way of managing thrips. Chemical control options include insecticide application (foliar/in-furrow) and/or seed treatments.

Related Publications

http://lubbock.tamu.edu/files/2017/05/Thrips_ENTO-069.pdf

Citations

Suhas Vyavhare, Assistant Professor and Extension Specialist David Kerns, Professor, IPM Coordinator and Extension Specialist. ENTO-069. 2017. Thrips. Texas A&M AgriLife Extension.

Bugwood Images

"C" shaped army cutworm larva. Photo credit: Robert Bowling, Texas A&M AgriLife Extension Service

Article author: David Kerns, Tyler Mays
Most recently reviewed by: Suhas Vyavhare & Kate Crumley (2020)

Common Name(s): army cutworm, Black Cutworm, Cutworms, dingy cutworm, granulate cutworm, mesquite cutworm, pale western cutworm, variegated cutworm

Description

There are a number of species of cutworm that may be encountered in Texas. Adults are typical “miller” type moths from the family Noctuidae. They are common moths found around porch lights. The moths are gray or brownish in appearance, although the hind wings are light gray or silverish in appearance. Their wingspans are 1 to 2 inches. The larvae are dingy, grayish-black and smooth-skinned and may reach 2 inches in length. The larvae are primarily nocturnal and will hide under plant debris and within soil cracks and crevasses during the day. When disturbed the larvae of most species will curl up into a C-shape.

There are four major groups of cutworms based on habitat and feeding behavior:

1) subterranean cutworms, such as the pale western cutworm that feed almost entirely below the soil surface on roots and underground stems;
2) tunnel dwellers such as the black cutworm which cuts a small, tender plant at the soil surface, pulls it into the tunnel and devours the plant;
3) surface feeders such as the granulate cutworm and the army cutworm which may cut seedling plants off at the surface or feed upon leaves of older plants;
and
4) climbing cutworms such as the variegated, dingy, and mesquite cutworms, may cut seedling plants and may also feed on foliage and flower buds.

Most significant plant injury from cutworms is associated with 3^rd instar or larger larvae. All regions of Texas may encounter cutworms of one or more types of cutworms.

: Army cutworm moth. Photo credit: John Capinera, University of Florida, Bugwood.org

: Army cutworm larvae. Photo credit: Pat Porter, Texas A&M AgriLife Extension Service

: Mesquite cutworm larva. Photo credit: Corteva Agriscience.

Habitat & Hosts

Cutworms are generalist and can be found feeding on a wide variety of plants. They are considered economic pests of corn, cotton, sorghum, vegetables and turf. Most damage occurs in the spring during crop establishment, where they can clip seedling plants off at the soil surface, resulting in poor stands. Infestations are most common in crops where thick cover crops or weeds exist at or within a few weeks before crop emergence. Cutworms are most evident when there are skips or sections of rows where all plants are missing, and cut plants can be seen laying upon the soil or partially buried. Some species, such as the mesquite cutworm, are usually most severe in July and August. In turf, cutworms may hide in aeration holes and clip nearby grass or burrow under the turf resulting in “ball mark” appearing spots. They are common in flower beds with thick spring flower growth, such as with petunias, and may be observed dispersing from areas where bedding cover and mulch is disturbed. Mesquite cutworms are occasionally major defoliators of mesquite in Texas.

: Black cutworms feeding on seedling cotton. Photos credit: David Kerns, Texas A&M AgriLife Extension Service

: Black cutworms feeding on corn.

Life Cycle

Most cutworms overwinter as larvae or pupae and emerge and mate during the spring. They lay their eggs on the various portions of the host plant. They typically seek out thickly vegetated areas to lay their eggs. The larvae will usually pass through 5-6 instars, but some species may have as many as 9 instars. They pupate in the soil, and most cutworm species require about 60 days to complete a full life cycle. There may be three to five generations per year in central and south Texas, depending on weather conditions and temperature.

Management

If you live in the State of Texas, contact your local county agent or entomologist for management information. If you live outside of Texas, contact your local extension for management options.

Cutworms usually do not require curative control unless unacceptable crop stand loss is likely. Seed treatments and Bt GMO traits can help prevent loss, but may not suffice where high populations of large cutworms exist, usually originating from cover crops or weeds. In turf, they are an erratic pest and are most attractive to overly fertilized and watered situations. Where they occur in turf, spot treatments will usually suffice.