Greenhouse Vegetable

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

Adult garden fleahopper. Photo credit: Whitney Cranshaw, Colorado State University, Bugwood.org

Article author: Tyler Mays
Most recently reviewed by: Blayne Reed & Ballinger (Vacant) (2021)

Common Name(s): Fleahopper, Garden fleahopper

Description

The garden fleahopper is a small insect roughly 1/16 of an inch in size and is black with yellow spots. The females have two forms: a long wing and a short wing. Males and long-winged females resemble tiny, tarnished plant bugs, and the wings have membranous tips that extend past the end of the abdomen. The forewings of short-winged female lack the membranous portion and resemble the forewings of beetles. Garden fleahoppers can be confused with flea beetles because of their size and jumping habits when disturbed; and aphids because of their small size, but aphids do not hop when disturbed.

Garden fleahoppers are commonly found on the underside of leaves or plant terminals and tend to hop, jump, or fly when disturbed. This insect feeds on the plant’s leaf tissue and young fruiting sites and will give the leaf chlorotic spots due to cells dying, resembling the damage caused by spider mites and can cause malformation or fruit shed of flowing fruit.

Origin and Distribution

The garden fleahopper is a native insect and is widely distributed in the eastern United State of America and Canada. It is also distributed as far west as the Rocky Mountains and southward into the Caribbean as well as Central and South America.

Habitat & Hosts

The garden fleahopper has a wide host range and can be found infesting field crops, ornamentals, and vegetable crops. Commonly infested field crops include alfalfa, clover, sweet clover, and has been observed infesting cotton on the Texas High Plains recently. Ornamental plants infested include chrysanthemum, daisy, marigold, and salvia. Several vegetable plants can be infested including bean, cabbage, cowpea, cucumber, eggplant, lettuce, pea, pepper, potato, squash, sweet potato, and tomato. Garden fleahoppers can also be found feeding on several weedy plants including bindweed, pigweed, mallow, ragweed, and many others.

Life Cycle

The garden fleahopper has an incomplete life cycle (hemimetabolous) and passes through an egg and 5 nymphal instars before becoming an adult. Their life cycle can be completed in roughly 30 days depending on environmental temperatures. Under cold temperatures this insect overwinters (diapause) in the egg stage, and in warmer climates it overwinters as the adult stage.

Eggs are inserted into the leaves and stems of plants at puncture wounds and dead plants are white to yellow in color. Once nymphs hatch from the egg, they are a pale green and become darker shades of green with each instar. The nymph passes through a total of five instars before becoming adults in 11 to 41 days based on the temperature.

Nymphs and adults feed on both leaf and stem tissue by piercing cells and feed on the cell’s contents. This feeding damage causes the cells to die and gives the leaves a stippling appearance with chlorotic spots, similar to the damage caused by spider mites and can cause early fruit shed in squaring cotton or malformation of the flower. Leaves heavily damaged by the garden fleahopper will die prematurely. This damage can also hinder the sale of plants grown for fresh leaves like lettuce and herbs, or the reduce ornamental sales because they are no longer aesthetically pleasing to the customer.

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.

The garden fleahopper can be suppressed easily with labeled insecticides, and therefore tend to be a pest of gardens rather than commercial production sites, but economic populations in both do occur. In gardens these fleahoppers can be managed with home/garden insecticides labeled for aphid management. The eggs are protected from insecticide application because they are inside the plant tissue, and a second insecticide application may be needed once the eggs hatch to reduce damage. Physically removing weedy hosts close to and within or nearby to production sites and gardens can keep garden fleahopper numbers from reaching damaging levels. Natural enemies of the garden fleahopper do exist and can be used to manage their population. These natural enemies include parasitic wasps and a predatory mite among other predacious insects and spiders mobile enough to catch the fleahopper. For management recommendation please contact your local County Extension Office.

Related Publications

Managing Cotton Insects in Texas. https://extensionentomology.tamu.edu/files/2018/03/ENTO075.pdf

Citations

Capinera, John L. 2020. Featured Creatures: Garden Fleahopper. University of Florida Publication: EENY-78. entnemdept.ufl.edu/creatures/veg/leaf/fleahopper.htm. Accessed Nov. 30, 2020

Bessin, Ric. 2019. Garden Fleahopper. University of Kentucky Cooperative Extension Publication:Entfact-307. entomology.ca.uky.du/ef307. Accessed Nov. 30, 2020

Vyavhare, Suhas S., Kerns, David, Allen, Charles, Bowling, Robert, Brewer, M., and Parajulee, M. 2019. Managing Cotton Insects in Texas. Texas A&M AgriLife Publication: ENTO-075. https://extensionentomology.tamu.edu/files/2018/03/ENTO075.pdf. Accessed Nov. 30, 2020

Bugwood Images

Adult Thrips. Photo by Dr. David Kerns, Texas A&M AgriLife Extension.

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

Common Name(s): Thrips

Description

Habitat & Hosts

Gorse Thrips. Photo by George Markin, USDA Forest Service, Bugwood.org

Life Cycle

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.

Related Publications

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

Bugwood Images

Adult chilli thrips. Photo by Dr. Mamoudou Setamou

Article author: Extension Entomologist at Weslaco (Vacant)
Most recently reviewed by: Pat Porter & Extension Entomologist at Overton (2020)

Common Name(s): Chilli Thrips, Strawberry Thrips, Yellow Tea Thrips

Description

Chilli thrips, Scirtothrips dorsalis, are tiny (> 2mm long), cigar-shaped insects. The adults are pale in color with black, feathery wings and dark spots forming incomplete stripes on the top of the abdomen. Immatures, called larvae, look similar to adults but are even smaller and lack wings. Distinguishing chilli thrips from other thrips species is difficult, requires magnification, and some knowledge of insect taxonomy. Chilli thrips are most often recognized based on their behavior and the type of damage they cause.

Origin and Distribution

Chilli thrips are thought to originally come from Southeast Asia although they are now widely distributed through most of the world including India, Japan, most of Africa, much of the Caribbean and South America, and are quickly becoming established in the United States. They were first detected in Florida in 1991 and in Southeast Texas in 2005. They have been intercepted at various ports-of-entry many times on a wide range of host plants and are likely established in many landscapes from Florida to Texas. This insect has the potential to become a wide-spread pest throughout the Southern and Pacific U.S.

Habitat & Hosts

Chilli thrips are known to infest an impressively wide range of host plants, more than 225 species from at least 40 different plant families, and the list will likely continue to grow as they expand their range. Their main wild, or native, host plants are in the bean family, Fabaceae. Among other known plant hosts are numerous important crops and ornamental plants such as citrus, corn, cotton, eggplant, melon, peanut, pepper, rose, strawberry, tobacco, and tomato.

Unlike similar looking species such as the Western flower thrips, which are often found in flowers feeding on pollen, chilli thrips feed on foliage and are typically found on the undersides of leaves near the mid-vein or borders of leaves. However, when population densities are high, some individuals may be found feeding on the upper surface of leaves.

: Chilli thrips on underside of cotton leaf. Notice how they stay near the veins. Photo by Holly Davis.

: Bronzing caused by chilli thrips feeding. Photo by Holly Davis.

These insects have piercing and sucking mouthparts they use to extract material from individual epidermal plant cells. Cell death leads to a silvering or bronzing of leaves and may cause them to curl, distort and/or turn brittle and drop from the plant. Infested plants can become stunted or dwarfed. Chilli thrips tend to favor tender plant tissue, flower buds, and young fruits and vegetables although all above ground parts of plants may be attacked. Feeding on fruits leads to scarring and, in severe infestations, corky tissues. Aesthetic damage to ornamental plants can lead to extensive losses in the nursery/horticultural industry.

In addition, chilli thrips are known to vector at least seven viruses to various plants including chilli leaf curl virus, peanut necrosis virus, tobacco streak virus, melon yellow spot virus, watermelon silver mottle virus, and capsicum chlorosis virus, although there are no reports at this time that they have been vectors of any of these viruses in Texas.

: Chill thrips on rose

: Chilli thrips damage. Texas A&M AgriLife Extension

Life Cycle

Female thrips insert anywhere from 60 – 200 microscopic, kidney-shaped eggs into plant tissue on or near leaf veins, terminal plant parts and floral structures where they cannot be detected by the naked eye. Eggs will hatch in 2-7 days. There are two larval stages that look similar to the adult but are smaller and lack wings. Larvae feed for 8-10 days before entering a non-feeding pupal stage that lasts 2-3 days. The length of time it takes to complete their life cycle varies depending on temperature and host plant but ranges from 14 – 20 days. Their large reproductive capacity and quick generation time means that chilli thrips populations can increase very quickly.

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.

Early detection of chilli thrips is important. Monitor for leaf silvering, bronzing or distortion, which can be mistaken for herbicide damage. To sample for thrips, tap the terminal portion of plants over a white piece of paper and examine with a hand lens or magnifying glass. In nurseries or greenhouses, yellow or blue sticky traps can be used to monitor for thrips.

Chilli thrips do have some natural enemies including minute pirate bugs (Orius sp.), lacewings, and predatory mites. While these predators may not always be able to provide adequate control of chilli thrips, it is important to preserve them by avoiding broad-spectrum insecticides such as pyrethroids and organophosphates, both of which also have a limited ability to manage chilli thrips . Biorational insecticides including horticultural oils, spinosad, and insecticidal soaps will kill larvae and adult thrips but have no residual activity so frequent application will be needed to control larvae as they emerge from eggs and/or new thrips migrate in. Products containing the conventional insecticide imidacloprid can be used as a soil drench or foliar spray and will provide control for a longer period of time with minimal impact on natural enemies. No matter what product you choose, it is important to rotate between different insecticide modes of action to reduce the risk of developing insecticide resistance.

Contributors: Scott Ludwig and Carlos Bogran

Related Publications

Chilli Thrips Control, Identification, and Management. 2016. Yan Chen, Steven Arthurs and Dennis Ring. LSUAg. Available here

Featured Creatures. Chilli Thrips. UF IFAS University of Florida. Available here

Pest Thrips of the United States: Field Identification Guide. Available here

Citations

Ananthakrishnan T. N. 1993. Bionomics of thrips. Annual Review of Entomology 38: 71-92

Chiemsombat, P., O. Gajanandana, N. Warin, R. Hongprayoon, A. Bhunchoth, P. Pongsapich. 2008. Biological and molecular characterization of tospoviruses in Thailand. Archives of Virology 153: 571-577.

Kumar, V., D. R. Seal, G. Kakkar, C. L. McKenzie, and L. S. Osborne. 2012. New tropical fruit hosts of Scirtothrips dorsalis (Thysanoptera: Thripidae) and its relative abundance on them in south Florida. Fla. Entomol. 95: 205 – 207.

Kumar, V., G. Kakkar, D. R. Seal, C. L. McKenzie, J. Colee, and L. S. Osborne. 2014. Temporal and spatial distribution of an invasive thrips species Scirtothrips dorsalis (Thysanoptera: Thripidae). Crop Protection 55: 80 – 90.

Mound, L. A., and J. M. Palmer. 1981. Identification, distribution and host plants of the pest species of Scirtothrips. (Thysanoptera: Thripidae). Bulletin of Entomological Research 71: 467-479.

Rao, R. D., V. J. Prasada, A. S. Reddy, S. V. Reddy, K. Thirumala-Devi, S. Chander Rao, V.Manoj Kumar, K. Subramaniam, T. Yellamanda Reddy, S. N. Nigam, D. V. R. Reddy. 2003. The host range of tobacco streak virus in India and transmission by thrips. Annals of Applied Biology 142: 365-368.

Reddy, D. N. R., and Puttswamy. 1983. Pest infesting chilli (Capsicum annuum L.) in the nursery. Mysore J. Agric Sci 17: 246 – 251.

Sanap, M. M., R. N. Nawale, 1987. Chemical control of chilli thrips, Scirtothrips dorsalis. Vegetable Science 14: 195 – 199.

Seal, D. R., M. Ciomperlik, M. L. Richards, W. Klassen. 2006. Distribution of the chilli thrips, Scirtothrips dorsalis Hood (Thysanoptera: Thripidae), within pepper plants and within pepper fields on St. Vincent. Florida Entomologist 89: 311-320.

Seal, D. R., W. Klassen, and V. Kumar. 2010. Biological parameters of Scirtothrips dorsalis (Thysanoptera: Thripidae) on selected hosts. Environ. Entomol. 39: 1389 – 1398.

Bugwood Images

Red and yellow color forms of the corn earworm.

Yellow, pink and green are common colors found in corn earworm larvae.

Article author: Pat Porter
Most recently reviewed by: Dalton Ludwick & Extension Entomologist at Weslaco (Vacant) (2020)

Common Name(s): Corn earworm, Cotton Bollworm, Soybean Podworm, Tomato Fruitworm

Description

Corn earworm belongs to the Order Lepidoptera (butterflies, moths and skippers) and the adult stage is a stout bodied, brownish to buttery-yellow moth with a wingspan of about 1 1/4 to 1 1/2 inches. There are usually darker bands present near the tips of the front and hind wings.

There are six larval instars (or stages). The first instar is about 1/16” long and the the 6^th instar can grow to 1 3/4 inches long. There is no one color for the larvae, and they can range from yellow to pink to green. Regardless of coloration there will be a darker stripe down the midline of the top of the larva, and somewhat wider stripes on the lateral edges of the body when viewed from above. A yellowish band is often found on the side of the larvae, and the band contains the dark, circular spiracles, the holes that let air into the insect’s body. Larvae have many microspines on the back and sides of the body, and these are not found on other common corn caterpillar pests. The head is orange to tan but may be more brownish in some larvae.

: Young corn earworm larva on hemp. Note the prominent microspines on the body.

: Green form of a late-instar corn earworm larva.

: Corn earworm adult. Kate Crumley.

Origin and Distribution

Corn earworm is native to the New World and overwinters in Texas, has multiple generations here, and is a threat throughout the growing season. In the United States, it is thought to be able to overwinter south of about 40 degrees north latitude, but as the summer progresses the moths fly north and infest the entire country and some of Canada.

Corn earworm adult showing typical buttery yellow color.

Habitat & Hosts

Corn earworm has an extremely wide food host range and can be found wherever its host plants grow. There are many non-crop plants on which the earworm can develop early in the year before crops and gardens are planted. Cultivated hosts include sweet corn, field corn, green beans, snap beans, cowpea, peas, peppers, eggplant, lettuce, sweet potato, rice, cotton, grapes, strawberry and many others. Typically the “worm” in sweet corn is the corn earworm. Corn earworm is also a very significant pest in hemp or cannabis production, and it is not uncommon to find larvae consuming buds and leaves.

Life Cycle

Eggs are laid singly on host plants. These are pearly white when laid and become somewhat more yellow over the course of the three days or so before they hatch. The larval stage, comprising six larval instars, lasts 12 to 15 days during the warm part of the growing season, longer when it is cooler. When fully grown, the 6^th instar larvae leaves the host plant, burrows into the ground and enters the pupal stage which lasts 10 – 15 days during the summer. Adults emerge from the ground, mate and disperse to lay eggs. Sometimes they disperse very

Freshly deposited corn earworm egg on corn silk.

long distances on storm fronts. Moths consume liquids and nectar as food and they are not damaging to plants.

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.

Management practices differ depending on which crop is being damaged. On field corn and sweet corn, the eggs are laid on silks, and the newly hatched larvae feed down the silk channel and then on the tip of the ear. In this case there is little opportunity to use insecticides because the larvae are in protected spaces. If insecticides are to be used, then they should be applied at the time of egg laying, usually with repeated applications from the time of silking until after the brown silk stage is reached.

Control is more straightforward when the earworms are feeding on the outside of the leaf or fruiting structure. In this case, sprayable formulations of Bacillus thuringiensis can be applied if a least toxic control method is desired. It must be noted, however, that corn earworms are now resistant to many of the Bt toxins in these sprayable insecticides because they built up resistance to them on Bt (GMO) corn in the last 25 years that corn has been used in the US. Synthetic pyrethroids can be effective, especially on smaller larvae, but it is also the case that corn earworms have developed significant levels of resistance to synthetic pyrethroids due to their widespread use in agriculture. Chlorantraniliprole is highly effective on corn earworm larvae, even large larvae. Spinosad and Spinetoram are very effective as well, as is the old insecticide carbaryl (Sevin). Agricultural producers have more options available and should consult a crop-specific control guide.

Citations

Corn Earworm. University of Florida Featured Creature: http://entnemdept.ufl.edu/creatures/veg/corn_earworm.htm.