Click for a hub of Extension resources related to the current COVID-19 situation.
COVID-19 Resources
Extension Entomology

Lesser Cornstalk Borer

by

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.

Bugwood Images

Corn Earworm (Helicoverpa zea)

by

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.

Bugwood Images

Angoumois Grain Moth

by

Article author: John Jackman
Most recently reviewed by: Pat Porter (2018)

Common Name(s): Angoumois Grain Moth, Grain moth

Description

Angoumois grain moths are occasionally found as pantry pests in homes, but they can be serious pests in commercial grain storage. Adult moths are a buff, tan or golden color and about 1/3 inch long. The wing span is 1/2 inch, rear edges of wings are fringed. Larvae are white with a yellowish to brown head and dark reddish-brown mouthparts. Larvae bore into kernels of cereal grains, pupate and emerge through a hole cut on the outer surface of the kernel.

Origin and Distribution

Grain storage, warehouses, bins, and pantries. Larvae feed on many types of whole grains. They prefer damp grain over dry grain.

Habitat & Hosts

They feed on stored grain, especially whole corn. The larvae require whole kernels or caked material for development. They bore into the kernel, pupate and emerge through a hole cut on the outer surface of the kernel. They are active at low temperatures and prefer barley, rye, corn, oats, rice and various seeds.

Life Cycle

Angoumois grain moth has a complete life cycle; egg, larva, pupa and adult, and it takes about about 5 weeks to complete development.  Adults can fly and are attracted to lights.

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.

In commercial/agricultural grain storage, control is complicated and requires the fundamental pest management steps of bin sanitation, grain leveling, aeration, monitoring etc. These things are beyond this fact sheet.

In homes and restaurants, control is simpler.

Nonchemical control.

The first step in controlling pantry pests is to find and eliminate infested items. Often all that is needed to solve the problem is to remove an infested package of flour, macaroni, or cake mix. But finding the source of an infestation is not always easy. Infested packages are usually the oldest, most difficult to reach foods in the pantry. Even unopened containers may be infested; some pests can easily penetrate plastic, waxed paper, and cardboard containers. Before buying an item in the store, check that the bag or container is well sealed and undamaged.

Good sanitation is important. Infestations often start in pet foods, spilled grains, or other foods. Clean up spilled food promptly. Discard old packages of grain and pasta. Vacuum and clean pantry areas periodically to remove spilled foods. Remove and clean underneath shelf paper. Caulk around pantry edges and in cracks and crevices to reduce areas where spilled food may collect.

Most pantry pest problems can be prevented by using all dried food within 2 to 4 months of purchase. Spices and other products kept for longer periods should be sealed in airtight containers.

Pet food can be a special problem.  The most commonly infested pantry items are birdseed and dog and cat foods. Store pet foods in well-sealed plastic buckets or storage containers and use them promptly. Clean the containers thoroughly before refilling them with food.

Occasionally, mice or other rodents can cause a persistent beetle infestation. Hoarded seed and grain in abandoned rodent nests can support a small population of pests. Old rodent bait that contains grain also can harbor insects. When controlling rodents, prevent insect problems by placing the bait where it can be retrieved and discarded after the rodents are controlled.

Heat or cold treatments can eliminate pests in some food items such as pet food, bulk grains and beans, and home-grown dried beans or peas. Put the product in the oven at 130 degrees F for 1 hour, or in the freezer for 7 to 14 days. To prevent an infestation, store foods that may attract pantry pests in the refrigerator or freezer.

Chemical control

On rare occasions, insecticides may be needed to control difficult infestations. Insecticides can reach inaccessible areas that cannot be easily cleaned; they can also help reduce heavy pest infestations more quickly.

Insecticide sprays may be applied to crevices and void areas around cupboards, drawers, and pantries. Before spraying, remove all food products, utensils, and containers from the treatment area. Allow the spray to dry before placing clean shelf paper on the shelves and returning food, utensils, or containers to the pantry.

Insecticide products that are labeled for use in food- storage areas generally contain ingredients that are short-lived and relatively safe to use in the home. Active ingredients of these products include pyrethrins, resmethrin, allethrin, and tetramethrin.

For areas where long-term residual control is de- sired, look for products containing synthetic pyrethroids, such as permethrin, esfenvalerate, cyfluthrin, or bifenthrin. Aerosol fog products can temporarily suppress infestations of flying insects, but these fogs will not kill pantry pests in food containers or protected locations.

Before using an insecticide, always make sure that the label says that the product may be used indoors and in kitchens. Never spray food, dishes, utensils, or cooking items with pesticides.

Bugwood Images

Rice stink bug

by


Most recently reviewed by: Tyler Mays & Pat Porter (2018)

Common Name(s): Rice Stink Bug

Pest Location

Row Crop

Description

Adult rice stink bugs are straw-colored, 3/8 to 1/2- inch long, somewhat elongated and flattened with forward pointing spines on the shield-like segment behind the head (pronotum).  Nymphs hatching from eggs are at first bright red with black markings. As they grow they begin to resemble adults but do not have fully developed wings or forward-pointing spines, but they have an intricate red and back pattern on the upper surface of their abdomens. Rice stink bug adults migrate from wild grasses to sorghum and rice when plants start to develop kernels or develop in and around fields on wild host plants.

Nymphal and adult feeding removes contents (endosperm) from developing seed (milk and soft dough stages) and results in an empty seed coat or shriveled kernels.  Yellow to black spots develop at feeding sites on rice kernels injured later (dough stage) and are often associated with microorganisms. This type of damage is commonly called “pecky rice”, and it has been correlated with reduced head yield and increased percent broken kernels in milled rice, a loss in quality or “grade.”

 

Habitat & Hosts

Wild host plants include barnyard grass and sedge (Cyperus sp.). Rice stink bugs can be collected from grasses with developing seed heads, such as Johnsongrass and rice.

Life Cycle

Winter (October through April) is spent in the adult stage near the ground in wild grasses. In April and early May adults become active and mated females lay clusters of 10 to 30 light green barrel-shaped eggs arranged in double rows on leaves and seed heads (panicles) of wild grasses, sorghum and rice. Nymphs hatch in about 5 days. They molt five times as they grow over a period of 15 to 28 days before becoming adults. Development from egg to adult occurs in 18 to 50 days, depending on temperature. Up to 5 generations can develop annually, with two or three developing on sorghum and rice.

Related Publications

See the website for the Texas A&M AgriLife Research and Extension Center at Beaumont.

Bugwood Images

Fall armyworm

by

Article author: Pat Porter
Most recently reviewed by: Ed Bynum (2018)

Common Name(s): Fall Armyworm

Pest Location

Row Crop

Description

Adult moths have a wingspan of approximately 1.5 inches. Females have front wings that are dark grey. Males have wings that have light and dark areas throughout and a whitish area near the tip.

Eggs are laid in groups of 100 to 200 and are covered by grey scales from the female moth’s body. The scales often impart a “fuzzy” appearance to the egg mass. Eggs are pearly green in color when newly laid and darken to a brown color in about 12 hours. Just prior to larval hatch, which occurs in 3 – 7 days, the eggs become blackish colored.

Small larvae range in color from a light cream when newly hatched to greenish after feeding, while medium-sized larvae range from light green to olive-green or brown. As with most larvae, identification in the first growth stage is difficult. To distinguish young fall armyworm larvae from those of the corn earworm and southwestern corn borer, look for a small black spot on the side of the first abdominal segment, just behind the last pair of true legs on the thorax. Fall armyworm has such a spot and the other two species do not.

Color characters are not very reliable for fall armyworm larval identification. Older larvae vary in color from light tan or green to blackish, and can change color as they mature. They have three fairly narrow stripes down the body as viewed from above; one down the centerline and two widely separated by darker areas. These may be variously colored, from whitish to yellow-white to reddish. There is a wider dark stripe down the side of the body and a wavy yellow-red blotched stripe just below this.

The best field identification characters do not involve color. Larvae have four pairs of abdominal prolegs and a pair of anal prolegs at the tip of the abdomen. They also have four dark spots arranged in a rectangle on the top of the eighth abdominal segment near the end of the abdomen.

Older fall armyworm can be distinguished from true armyworm, corn earworm, and the corn borer species by the presence of a white inverted “Y” mark on the front of the dark reddish-brown, mottled, head capsule. This character may be absent on younger larvae.

Origin and Distribution

Fall armyworm is native to the Western Hemisphere and overwinters in areas of mild climate.

Life Cycle

Fall armyworm adults migrate north from overwintering sites in south Texas and northern Mexico and become established in corn and other crops in the spring. Fall armyworm does not overwinter in the northern part of Texas and does not undergo winter diapause. This species has a very broad host plant range that includes wheat, alfalfa, sorghum, corn, and other crop and non-crop plants.

Fall armyworm larvae feed 2 to 3 weeks. Mature larvae burrow an inch or two in the soil to pupate. Pupation lasts for about 2 weeks. Pupae are smooth and reddish brown to dark brown in color and look much like the pupae of other lepidopterous pests of corn. Adults then emerge to mate and females can lay up to 1,100 eggs. Adults live about two weeks. There are several generations each year, and migratory moths may continue to arrive throughout the season.

There are two host strains of fall armyworm, one of which feeds predominately on corn, sorghum and cotton (known as the corn strain), and the other, the rice strain, feeds on rice, Bermudagrass and Johnsongrass.

The fall armyworm and true armyworm get their names from the behavioral trait that causes larvae to move from one field to another when they have consumed all available food. In essence, they are said to move like an army.

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.

Home garden control options include:

Related Publications

Bugwood Images