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Extension Entomology

Lesser Cornstalk Borer

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Article author: Kate Crumley
Most recently reviewed by: Tyler Mays & Danielle Sekula (2021)

Common Name(s): Lesser Cornstalk Borer

Description

The lesser cornstalk borer is a small, yellow to black moth with sexual dimorphism that varies by location. This moth species is a pest on a variety of grain and legume crops, with larvae that feed by tunneling into the stem of the host plant.

Origin and Distribution

The lesser cornstalk borer is native to the United States. It can be found from Maine to California, and has been documented in Hawaii, but is most often found in sandy soils in the southeastern United States. It can also be found in Mexico, Central, and South America.

Habitat & Hosts

The lesser cornstalk borer is a polyphagous pest that feeds on a variety of crops. Vegetable and legume crops are often damaged, and it has a variety of weedy hosts like crabgrass, johnsongrass, wild oats, bermudagrass, wiregrass, goosegrass, and nutsedge.

Life Cycle

Lesser cornstalk borer eggs are oval, and are 0.35mm – 0.43 mm in width, and green when first laid, but turn pink after 8- 24 hours. Eggs turn deeper red as they near hatching, and are a deep iridescent crimson immediately before. Eggs take between 2- 3.5 days to hatch depending on temperature. Larvae that can be found in silk tunnels radiating horizontally from the stems of their host plants immediately below the soil surface. The silk tubes are usually between two or three inches long, depending on the age of the larvae. Larvae normally have 6 instars, but can range from 5- 9, and range from 1.3 mm to 20.8 mm long. The larval stage lasts about 20 days when not overwintering. Pupae can be found in the silk tunnels near base of the plant, or loose in the soil. They are yellow early, and turn dark brown to nearly black before adults eclose. They range from 7.6 mm to 9.6 mm in length. The pupal stage can last from 7- 10 days when not overwintering. Adult moths are 8-9 mm long brown moths with sexual dimorphism, and color patterns that vary based on location. Adults live for about 10 days, and are most active at night.

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.

Damage from the lesser cornstalk borer is caused by feeding, which tunnels into the stem of the plant or girdles the base of the plant. Wilting is one of the early symptoms of infestation, and can result in a poor crop stand. Insecticides can be used to control this pest, but need to be applied to the root zone, either in the seed furrow or banded over the seed bed. Modified planting practices can be used to minimize damage. Insect populations increase later in the growing season, so early planting can help. Tillage and weed control also help minimize insect populations in the environment, but conservation tillage can also help. Conservation tillage can allow larvae to feed freely on crop residue and organic matter, which can spare seedlings.

Related Publications

http://entnemdept.ufl.edu/creatures/field/lesser_cornstalk_borer.htm#damage

https://entomology.ca.uky.edu/ef129

Citations

All JN, Gallaher RN, Jellum MD. 1979. Influence of planting date, preplanting weed control, irrigation, and conservation tillage practices on efficacy of planting time insecticide applications for control of lesser cornstalk borer in field corn. Journal of Economic Entomology 72: 265-268.

Bessin R. 2004. The common stalk borer in corn. University of Kentucky, Entomology. University of Kentucky, Lexington, KY. http://www.ca.uky.edu/entomology/entfacts/ef100.asp (5 September 2008)

Biddle AJ, Hutchins SH, Wightman JA. 1992. Pests living below ground, Elasmopalpus lignosellus: Lesser cornstalk borer, pp. 202-203. In McKinley RG. [editor] Vegetable Crop Pests. CRC press, Boca Raton, FL.

Capinera JL. 2001. Handbook of Vegetable Pests. Academic Press, San Diego. 729 pp.

Chang V, Ota AK. 1987. The lesser cornstalk borer: a new important pest of young sugarcane, pp. 27-30 In Annual Report, 1986. Experiment station. Hawaiian Sugar Planter’s Association, Pahala, HI.

Chapin JW. (1999). Lesser cornstalk borer on peanut. Entomology insect information Series. http://entweb.clemson.edu/eiis/pdfs/ag21.pdf (20 August 2008).

Funderburk JE, Boucias DG, Herzog DC, Sprenkel RK, Lynch RE. 1984. Parasitoids and pathogens of larval lesser cornstalk borers (Lepidoptera: Pyralidae) in northern Florida. Environmental Entomology 13: 1319-1323.

Funderburk JE, Herzog DC, Mack TP, Lynch RE. 1985. Sampling lesser cornstalk borer (Lepidoptera: Pyralidae) adults in several crops with reference to adult dispersion patterns. Environmental Entomology 14: 452-458.

Gardner WA, All JN. 1982. Chemical control of the lesser cornstalk borer in grain sorghum. Journal of Georgia Entomological Society. 17: 167-171.

Isely D. 1944. The lesser cornstalk borer, a pest of fall beans. Journal of Kansas Entomological Society. 17: 51-57.

Leuck DB. 1966. Biology of the lesser cornstalk borer in south Georgia. Journal of Economic Entomology 59: 797-801.

Luginbill P, Ainslie GG. 1917. The lesser cornstalk borer. U.S. Department of Agriculture Bulletin 539. 27 pp.

Lynch RE, Klun JA, Leonhardt BA, Schwarz M, Garner JW. 1984. Female sex pheromone of the lesser cornstalk borer, Elasmopalpus lignosellus (Lepidoptera: Pyralidae). Environmental Entomology 13: 121-126.

Mack TP, Backman CB. 1984. Effects of temperature and adult age on the oviposition rate of Elasmopalpus lignosellus (Zeller), the lesser cornstalk borer. Environmental Entomology. 13: 966-969.

Mack TP, Davis DP, Backman CB. 1991. Predicting lesser cornstalk borer (Lepidoptera: Pyralidae) larval density from estimates of adult abundance in peanut fields. Journal of Entomological Science 26: 223-230.

Mack TP, Davis DP, Lynch RE. 1993. Development of a system to time scouting for the lesser cornstalk borer (Lepidoptera: Pyralidae) attacking peanuts in the southeastern United States. Journal of Economic Entomology 86: 164-173.

Metcalf CL, Flint WP, Metalf RL. 1962. Lesser cornstalk borer, pp. 497-498. In Destructive and useful insects. McGraw-Hill Book Company, San Francisco, CA.

Nuessly GS, Webb SE. (2007). Insect management for sweet corn. EDIS. http://edis.ifas.ufl.edu/IG158 (7 May 2020).

Riley CV. 1882. The smaller corn stalk-borer. U. S. Department of Agriculture Report 1881: 142-145.

Sanchez, Louis O. 1960. The biology and control of the lesser cornstalk borer, Elasmopalpus lignosellus.

Schaaf AC. 1974. Jumping borer, Elasmopalpus lignosellus, pp. 31-34. In Handbook of pests of sugarcane. Tech Bull 1/75. Sugar Industry Research Institute Mandeville, Jamaica.

Smith JW Jr, Barfield CS. 1982. Management of preharvest insects, pp. 250- 325. In Pattee HE, Young CT (editors), Peanut science and technology. American Peanut Research Education Society, Yoakum, TX.

Smith Jr JW, Johnson SJ, Sams RL. 1981. Spatial distribution of lesser cornstalk borer eggs in peanuts. Environmental Entomology 10: 192-193.

Smith Jr JW, Johnson SJ. 1989. Natural mortality of the lesser cornstalk borer (Lepidoptera: Pyralidae) in a peanut agroecosystem. Environmental Entomology 18: 69-77.).

Tippins HH. 1982. A Review of Information on the Lesser Cornstalk Borer Elasmopalpus lignosellus (Zeller). Georgia Agricultural Experiment Station Special Publication 17. 65 pp.

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Corn Earworm (Helicoverpa zea)

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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 6th 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.

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

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 6th 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

Corn earworm egg on corn silk.

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.

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Sweetpotato whitefly

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Article author: Extension Entomologist at Overton
Most recently reviewed by: Pat Porter & David Kerns & Suhas Vyavhare (2018)

Common Name(s): Silverleaf Whitefly, Sweetpotato whitefly

Description

The sweetpotato/silverleaf whitefly, Bemisia tabaci Gennadius (Hemiptera: Aleyrodidae), is a global pest of many economically important host plants (Simmons et al. 2008) such as eggplant, tomato, sweet potato, cucumber, garden bean (Tsai & Wang 1996), cotton, and poinsettias, to name a few. Similar to other sucking insect pests, sweetpotato whiteflies reduce plant vigor, growth, and can even cause mortality by piercing plant tissue and feeding on plant phloem (Bryne & Miller 1990). Whiteflies excrete waste as a sugary solution, known as honeydew. Excessive honeydew can result in inoculation of a complex of fungi, resulting in a black layer or crust forming on the surface, commonly referred to as sooty mold. In addition to causing detrimental damage by feeding, B. tabaci has been recorded to vector more than 100 plant viruses (Jones 2003), which can result in rapid widespread crop loss. Some of these viruses in Texas include Cucurbit leaf curl virus (Brown et al. 2000) and cucurbit yellow stunting disorder virus (Kao et al. 2000).

Adult whiteflies resemble very small (1 mm or 3/64-in) white moths. When disturbed, adult whiteflies will often leap off the plant and fly a short distance before landing on a nearby surface. Whitefly nymphs, especially younger nymphs, can be hard to see with the naked eye. Whitefly nymphs often blend with the leaf due to their color and relatively flat shape. The final nymph instar is often referred to as a pupa, when they become darker yellow color and are more round, making them easier to distinguish on the leaf. Once they emerge as adults, their shed ‘skin’ stays on the leaf, known as an exuvia. The exuviae stay on the leaf and resemble a small empty shell.

Adult sweetpotato whiteflies can be confused for other whiteflies that may occur in Texas, with two other common ones being the bandedwing whitefly (Trialeurodes abutiloneus) and greenhouse whitefly (Trialeurodes vaporariorum).

Origin and Distribution

Sweetpotato whiteflies are considered a global pest, however there are certain biotypes or species that are more prevalent in different parts of the world. Texas has populations of both MEAM1 (B biotype) and MED (Q biotype) whitefly.

Life Cycle

Whiteflies are closely related to mealybugs and scale insects. Female adult whiteflies lay eggs, often in a circular pattern as a result of the female using her feeding proboscis as a pivot while laying eggs. Eggs are pear-shaped and approximately 0.2 mm long (CABI MEAM1). On cotton, eggs take between 5 to 22.5 days to emerge as crawlers when held at 16.7ºC (62F) or 32.5ºC (90.5) (Butler et al. 1983), respectively. After emerging from the eggs, a mobile stage known as “crawlers” find a place nearby to settle. Once settled, whitefly nymphs are considered rather immobile until after metamorphosis. Bemisia tabaci undergo four instar stages before pupation and becoming a winged adult. The total development time from egg to adult varies from 16.6 days at 30ºC (86F) to 65.1 days at 14.9ºC (59F) in cotton (Butler et al. 1983). Adult females lay approximately 72 – 81 eggs and survive an average of 8 to 10.4 days in controlled studies (Butler et al. 1983).

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.

Sweetpotato whitefly taxonomy is currently under revision, but it is generally agreed upon that there are specific groups of sweetpotato whiteflies that exhibit different host plant preferences, reproductive rates, and resistance to insecticides. Originally, it was thought that sweetpotato whiteflies were composed of several different ‘biotypes’, a couple well-known ones including the “B” (MEAM1) and “Q” (MED) biotypes, but now has been proposed to be made up of at least 34 morphologically indistinguishable species (Tay et al. 2012). The MEAM1 whiteflies have greater reproductive potential than the MED whiteflies, however the MED whiteflies are resistant to several different insecticides, such as pyriproxyfen and imidacloprid. Growers are encouraged to either use biological control to prevent further rise of resistance to insecticides, or rotate between insecticides that are known to be effective against both MEAM1 and MED whiteflies. See “Related Publications” below for more information.

Whitefly populations can be monitored using yellow sticky cards or searching the undersides of leaves for eggs, nymphs, pupae, exuviae, or adults. Look for other signs of infestation, such as honeydew, sooty mold, or chlorosis.

In many regions of Europe and North America, sweetpotato whiteflies in protected culture (i.e. greenhouses) are managed through regular releases of biological control agents. In the USA, commercially available biological control agents that have demonstrated potential management of sweetpotato whiteflies include Eretmocerus eremicus (Hoddle and van Driesche 1999) and Amblyseius swirskii (Calvo et al. 2010).

Insecticidal management of sweetpotato whiteflies are highly dependent on commodity, location, setting, and thresholds. Some active ingredients that have demonstrated efficacy against both MEAM1 and MED sweetpotato whiteflies include:

  • Abamectin
  • Abamectin + Bifenthrin
  • Acetamiprid
  • Beauvaria bassiana
  • Cyantraniliprole
  • Dinotefuran
  • Isaria fumosorosea
  • Horticultural Oil*
  • Insecticidal Soap*
  • Pyridaben
  • Pyrifluquinazon
  • Spiromesifen
  • Spirotetramat
  • Thiamethoxam

(Kumar et al. 2017)
*Beware of application in extreme heat and exposure to sun. Can cause leaf burn/phytotoxicity.

For more information, consult one of our related publications below for whitefly management specific to your situation.

Related Publications

CABI Bemisia tabaci (MEAM1) fact sheet: https://www.cabi.org/isc/datasheet/8925#8440C199-FEDE-40E6-AED0-E7C195DC4E5B

CABI Bemisia tabaci (MED) fact sheet: https://www.cabi.org/isc/datasheet/112682

Byrne, David N. (1991). Whitefly biology. Annual Review of Entomology, 36: 431 – 457.

Suhas et al. (2018). Managing Cotton Insects in Texas. Texas A&M AgriLife Extension. https://extensionentomology.tamu.edu/resources/management-guides/managing-cotton-insects-in-texas/other-pests/

Kumar et al. (2017). Whitefly (Bemisia tabaci) management program for ornamental plants. UF/IFAS Extension. https://mrec.ifas.ufl.edu/lso/bemisia/Documents/EDIS-Whitefly-Management-Program.pdf

Citations

Brown et al. (2000). Cucurbit leaf curl virus, a new whitefly transmitted geminivirus in Arizona, Texas, and Mexico. The American Phytopathological Society, 84(7): 809.

Butler et al. (1983). Bemisia tabaci (Homoptera: Aleyrodidae): Development, oviposition, and longevity in relation to temperature. Annals of the Entomological Society of America, 76: 310 – 313.

Byrne & Miller (1990). Carbohydrate and amino acid composition of phloem sap and honeydew produced by Bemisia tabaci. Journal of Insect Physiology, 36: 433 – 439.

CABI Bemisia tabaci (MEAM1) fact sheet: https://www.cabi.org/isc/datasheet/8925#8440C199-FEDE-40E6-AED0-E7C195DC4E5B

Calvo et al. (2011). Control of Bemisia tabaci and Frankliniella occidentalis in cucumber by Amblyseius swirskii. 56(2): 185 – 192.

Hoddle, M. and van Driesche, R. G. (1999). Evaluation of inundative release of Eretmocerus eremicus and Encarsia formosa Beltsville strain in commercial greenhouses for control of Bemisia argentifolii (Hemiptera: Aleyrodidae) on poinsettia stock plants. Biology and Microbial Control, 92(4): 811 – 824.

Jones D (2003). Plant viruses transmitted by whiteflies. European Journal of Plant Pathology, 109: 197 – 221.

Kao et al. (2000). First report of Cucurbit yellow stunting disorder virus (genus Crinivirus) in North America. The American Phytopathological Society, 84(1): 101.

Kumar et al. (2017). Whitefly (Bemisia tabaci) management program for ornamental plants. UF/IFAS Extension. https://mrec.ifas.ufl.edu/lso/bemisia/Documents/EDIS-Whitefly-Management-Program.pdf

Simmons et al. (2008). Forty-nine new host plant species for Bemisia tabaci (Hemiptera: Aleyrodidae). Entomological Science, 11: 385 – 390.

Tay et al. (2012). Will the real Bemisia tabaci please stand up? PLoS ONE, 7(11): 7 – 11.

Tsai & Wang (1996). Development and reproduction of Bemisia argentifolii (Homoptera: Aleyrodidae) on five host plants. Environmental Entomology, 25(4): 810 – 816.

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Soybean Podworm

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Article author: David Kerns, Pat Porter
Most recently reviewed by: (1970)

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

Description

The soybean podworm is also known as the corn earworm, cotton bollworm, sorghum headworm and tomato fruitworm and can be found on many garden and farm crops and non-crop vegetation. In most soybean production, soybean podworm is referred to as corn earworm. Adults have buff-colored wings and rather stout bodies. The wingspan is approximately 1½ inches. They are good fliers and can easily move from field to field and often arrive in large numbers on storm fronts. The moths only feed on nectar and are not pests.

However, each female can lay 500 or more eggs. The eggs are laid singly and, when new, are pearly white. The color changes to a yellow/dull white tint over time before hatching. Small caterpillars look much like the small caterpillars of other species, and it is difficult to identify them without a microscope. Soybean podworm caterpillars have many microspines on the back and sides of the body, and these are not found on most other common caterpillar pests. Larvae have a tan head and alternating dark and light stripes running lengthwise down the body, and they have numerous tubercles (dark spots) with long spines. Other pest species have stripes as well, but they do not have the abundance of microspines and tubercles, and a 10x hand lens will allow differentiation. There is no “typical” larval color, and it is common to find larvae that are either light green, dark green to grey green, or pink. Full grown larvae are approximately 1.5 inches long.

A very similar pest that may be found infesting soybean is the tobacco budworm. Eggs and larvae of soybean podworm and tobacco budworm indistinguishable without fine magnification. Tobacco budworm larvae have a tooth-like projection, called a retinaculum, on the inside surface of the mandibles and fine short hairs on the first, second and eighth abdominal projection (tubercle) which bear a single, prominent spine. If the projection and hairs are absent, this indicates a podworm. Damage and management of these two pests are the same in soybean. Soybean podworm may be distinguished from other soybean infesting caterpillars primarily based on the number of pairs of abdominal prolegs.

 

Origin and Distribution

The soybean podworm is a New World insect (Western Hemisphere) and is present throughout this region. It overwinters only in areas with mild winters, but flies to other areas during the course of the spring, summer and fall.

Habitat & Hosts

Soybean podworm has a very wide host range, and in Texas is usually the caterpillar found in ears of corn. Other cultivated hosts include tomato, sorghum, cotton, sunflower, squash, watermelon, potato, sweet potato, asparagus, artichoke, cowpea, snap pea, green bean, cabbage, cantaloupe, collard, cucumber eggplant, pepper, watermelon and others. The first generation of soybean podworm primarily develops on wild hosts, principally clovers. The second generation develops primarily on corn. Among soybean podworm hosts, corn is the most suitable of all hosts. The third and fourth generations generally occur in other agronomic host crops such as soybean, cotton, and grain sorghum with the fifth generation occurring primarily on volunteer crop plants after harvest and on other non-crop wild hosts.

Host preference of soybean podworm is positively correlated to plant maturity and it strongly prefers plants in the flowering stage. Thus, egg lay in soybean most often occurs during flowering or the R1-R2 stages. Later infestations may occur but are much less common. High infestations of soybean podworm often follow pyrethroid applications during bloom, due to destruction of natural enemies.

Although a less common pest of soybean in Texas, in other parts of the southern U.S. soybean podworm is often the most economically important insect pest of soybean. Soybean podworm causes damage to soybean through defoliation and from consuming pods. Early instars typically feed on blooms and and leaves. Feeding on blooms is not considered economical and defoliation by podworms alone is usually not severe enough to warrant control. Most damage is associated with 3rd-6th instar larvae which will feed upon leaves, but more importantly soybean pods. One larva can consume 15-20 flat pods or 6-10 older pods.

 

Life Cycle

Adults are quite mobile and can lay eggs on any host that is at a susceptible stage. Eggs are often laid near or on fruiting structures, but they can be laid on leaves and stems as well. Eggs hatch in 3-5 days and there will be five to six larval instars, each separated by a molt to a larger caterpillar. The larval stage lasts from 13 to 31 days depending on temperature. Insects develop faster under higher temperatures. After the last larval stage, the larvae move to the soil and construct a burrow where they will remain while in the pupal stage, which lasts from 10 – 25 days depending on temperature. Adults then emerge and will live for an average of 10 days, some more and some less. Soybean podworm overwinters in south Texas, and often flies north carried on storm fronts. There are several generations per year and the insect can be expected to be present for most of the growing season in the south, but only increases gradually in number in northern parts of the state. However, the growing season starts later in the north, and soybean podworm is usually quite abundant by the time vegetables and other crops reach susceptible stages.

Soybean podworm larvae are cannibalistic but in soybean they are usually not confined to groups in small areas so this behavior is inconsequential.

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.

Most states have well defined action threshold to aid in management decision making. Sampling for soybean podworm usually involves sweep net or drop cloth. In much of the southern U.S., pyrethroid resistance is common in soybean podworm populations so caution should be used if using a pyrethroid for podworm control. Commonly used insecticides for soybean podworm and tobacco budworm include products containing chlorantraniliprole, spinetoram or spinosad. Additionally, the nucleaopolyhedrovirus, i.e. Heligen, has proven to be an effective alternative to chemical insecticides.

Related Publications

Citations

Adams, B.P., D.R. Cook, A.L. Catchot, J. Gore, F. Musser, S.D. Stewart, D. L. Kerns, G. M. Lorenz, J.T. Irby and B. Golden. 2016. Evaluation of corn earworm, Helicoverpa zea, (Lepidoptera: Noctuidae), economic injury levels in Mid-South reporductive stage soybean. J. Econ. Entomol. 109: 1161–1166.

Flanders, K. and R. Smith. 2008. Identifying caterpillars in field, forage, and horticultural crops. Alabama Cooperative Extension, ANR-1121. http://www.aces.edu/pubs/docs/A/ANR-1121/ANR-1121.pdf.

Hartstack, A. W., J. P. Hollingsworth, R. L. Ridgway, and J. R. Coppedge. 1973. A population dynamics study of the bollworm and the tobacco budworm with light traps. Environ. Entomol. 2: 244–252.

Mueller, A. J., and B. W. Engroff. 1980. Effects of infestation levels of Heliothis zea on soybean. J. Econ. Entomol. 73: 271–275.

Smith, R. H., and M. H. Bass. 1972. Soybean response to various levels of podworm damage. J. Econ. Entomol. 65: 193–195.

Bugwood Images

Click Beetle / Wireworm

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Most recently reviewed by: Janet Hurley & Pat Porter (2018)

Common Name(s): Click beetle, Wireworm

Description

Click beetles are elongated, parallel-sided and usually bear backward projections on the side corners of the shield behind the head (pronotum). They are somewhat flattened and range in size and color by species. Smaller species are about 1/4 inches long. Most species are brown to black in color, although some have reddish and yellowish colors and patterns. The eyed click beetle, Alaus oculatus (Linnaeus), reaches 1-½ inches in length and is beautifully marked with prominent oval eye spots on the pronotum and mottled gray wing covers. When placed on their backs, these beetles characteristically “click”, snapping their thoracic segments (prothorax and mesothorax) to cause their bodies to flip in the air to right themselves. Larvae, called “wireworms,” are usually hard-bodied, brownish, ½ to 2-½ inch long and cylindrical, with three pairs of tiny true legs behind the head and a flattened, and an ornamented shield-like segment on the tail end of the body.

The false click beetles (Eucnemidae) are similar to click beetles, and some species can even “click.” They are less common and usually occur in wood just beginning to decay. The Texas beetle, Brachypsectrida fulva LeConte (Coleoptera: Brachypsectridae) somewhat resembles a 3/16-inch long click beetle without the clicking mechanism. There is only one species in this family.

Habitat & Hosts

Larval stages (wireworms) damage seeds and seedlings of a wide variety of crops including alfalfa, beans, beets, clovers, corn, cotton, grasses, small grains (wheat, oats, etc.) many vegetable and bedding plants.  They also tunnel into potato and sweet potato tubers. Larvae of some species, such as the eyed click beetle, occur in dead trees and rotting stumps and logs.  Adults of Deilater have two light-producing spots on the thorax and one of the abdomen, somewhat similar to that of lightning bugs (Lampyridea).

In some years, adults are extremely numerous and enter homes and other structures in significant numbers. Adults do not damage plants.

Life Cycle

Biology varies by species. In general, adults and larvae overwinter in the ground, becoming active in the spring. Adult females dig burrows and lay eggs around the base of host plants. Eggs hatch within a few weeks and larvae develop through several molts over a period of time from several months to over 4 years. They pupate in the cells within the soil in late summer or fall, and emerge as adults a few weeks thereafter. Generations can greatly overlap.

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.

Minimize wireworm infestations through clean cultivation and clean fallowing. Infestations are most severe in no-tillage or reduced-tillage situations, particularly following alfalfa, cover crops, or grain. Planting shallow and under warm conditions often allows cotton seeds to germinate quickly so plants can outgrow wireworm injury potential rapidly.

Larvae of some species damage seeds and underground parts of crop plants. Management in agricultural settings varies by crop, and growers should consult publications specific to the crop being grown. It is often the case that significant stand damage requires a replant of the crop.

Wireworm damage can be difficult to diagnose, in part because the larvae are highly mobile in the soil and may no longer be present. Look for chewed tissue on seeds and young plant parts below ground.

Wireworm damage to cotton seedlings. Photo credit: Patrick Porter.

Wireworm damage to cotton seedlings. Photo credit: Patrick Porter.

 

Time-lapse video showing wireworm larvae seeking shelter in soil. Video credit: Patrick Porter.

Related Publications

Insects in the City “Click beetles gone wild”

Wireworms at cottonbugs.tamu.edu

Bugwood Images