CUTWORMS IN THE HOME GARDEN AND LANDSCAPE J. W. Stewart* Cutworm moths are found in a variety of colors There are four distinct groups ofcutworms based with an equal variation in wing markings. Moths have on habitat and feeding behavior. Each group attacks a wingspread of 1 to 2 inches and normally exhibit a and damages plants differently. One or more exam­ grayish-brown to black body and wing color. The dark ples for each category are discussed in the following gray forewings are usually marked with light and dark paragraphs. spots or narrow bands. Cutworm larvae usually ap­ Members of this group pear as dingy, grayish-black, smooth "worms" that Subterranean cutworms. feed almost entirely below the soil's surface on roots curl into a ball or tight "C-shape" when disturbed. and underground stems. The pale western cutworm, Agrotis orthogonia (Morr.), is an important member ~,!,,?\,>, no .,; ~. of this group. The moth lays its eggs on the soil. The "!I'lj. r /~~ \. 0<a.. tiny larva spends the winter inside the egg until early " ".)/ \~'-~ ..-~~ ~,rr,,-,'7oJ"" spring when it emerges to feed. Initially the young larva feeds on leaves of the host plant but quickly assumes the subterranean feeding habit. Although there is only one generation annually, this species does considerable damage to vegetables and other agricultural crops throughout the western half of the Figure 1. Cutworm laNa. United States and Canada. General Life History Tunnel dwellers. Several cutworm species form and live in tunnels. One important member of this Several species of cutworms exist in Texas. Their group is the black cutworm, Agrotis ipsilon (Huf­ life histories vary conSiderably but all must pass nagel). This particular cutworm cuts a tender plant at through the egg, larva and pupa stage before reaching the soil surface, pulls it into the tunnel and devours adulthood. The moth deposits eggs which hatch into the plant. Several generations of this species are small larvae (caterpillars). The larvae have chewing produced annually. The greatest damage usually oc­ mouthparts and damage plants by their feeding activi­ curs during April, May and June when the first gen­ ty. As the larvae grow they shed their skin periodi­ eration is feeding. Outbreaks of this insect fre­ cally until reaching a length of 1 to Ilh inches at quently occur on land subject to overflow. The black maturity when they enter a non-feeding pupal stage cutworm overwinters as either a larva or pupa. (cocoon) from which they emerge as moths. The adult moths have siphoning mouthparts and feed only on Surface feeders. The army cutworm, Euxoa au­ nectar; their feeding causes no apparent damage to xiliaris (Grote), is classified as a surface feeder, and is plants. a serious pest of ornamental plants. The worms are active during the night when they cut offsmall plants Rainfall and other weather conditions affect the at or near the soil surface and feed on the plant. abundance ofcutworms. Heavy rains may impair the moths' egg laying activities or force the larvae to the During the day the worms either hide in the soil or under mulch or surface trash. Because oftheir ability surface because offlooding. When this occurs, para­ to tole,rate cold temperatures, cutworms often are sites and predators attack and destroy many ofthem. present in early spring when temperatures are Damage slightly above freezing. There is one generation an­ nually and the insect spends the winter months as a Cutworms attack almost every garden vegetable, larva in the soil or in plant debris on the soil. fruit tree, lawn grass and ornamental plant in the home garden and landscape. Seedling plants are par­ The granulate cutworm, Feltia subterranea (F.), ticularly vulnerable to cutworms since the main stem is an important pest of garden vegetables in Central is tender and can be severed easily. and South Texas. This surface-feeding cutworm can do tremendous damage in little time. The winter is passed in the pupal stage in the soil. There can be *Area Extension entomologist, Uvalde, The Texas A&M Univer­ three to five generations annually in Texas, depend­ sity System. ing on weather conditions and temperature. Texas Agricultural Extension Service • The Texas A&M University System • Daniel C. Pfannstiel, Director • College Station, Texas Climbing cutworms. Several species of climbing Cutworm control in established vegetable and cutworms feed on the foliage, stems, leaves and flower gardens andin lawns is another matterentirely. fruits ofmany plants. Like other cutworms they feed Application rates vary according to type of plants primarily at night and hide in leaf litter or under and species of cutworm. Table 2 lists certain insecti­ boards or rocks during the day. However, some feed­ cides that control cutworms when properly applied. ing may occur on cool, cloudy days. The variegated cutworm, Peridroma saucia Table 2. Insecticides for cutworm control in vegetable gardens, flower gardens and lawn areas. (Hubn.), is an important climbing cutworm. In most areas of Texas, this cutworm spends the winter as a Insecticide Formulations Restrictions 1 larva. The number of generations per year varies Carbaryl (Sevin®) wettable powder Read and follow bait manufacturers in­ somewhat, but the generation occurring during April structions on the in­ to July accounts for most of the damage. Diazinon emulsifiable concen­ secticide container. (Spectracide®) trates' The identity of the wettable powder specific pest or Cultural Control granules pests to be control­ Cultural control techniques are very important in (lawn only) led or vegetables on Trichlorfon (Dylox®) emulsifiable concen­ which the products reducing cutworms. These controls make the habitat trate' are to be used and unfavorable for cutworm survival. A few control bait other conditions of methods are listed below. proper use are a part • Keeping gardens plowed and weed-free when of the product label. not planted with desired crops is helpful since 'Wettable powder and emulsifiable concentrates are to be mixed with water before applying. cutworm moths are attracted to grassy areas to deposit eggs. Handling and Mixing Insecticides • Cutworms seek hiding places to pass the day­ Insecticides are sold under brand or trade names. light hours. One may take advantage ofthis be­ Always refer to the statement ofactive ingredients on havioral trait by placing small boards in the gar­ the label to determine the specific insecticide in the den for cover. Cutworms congregate beneath formulation. Mix and apply the material exactly as the boards and can be destroyed easily by hand. directed on the label. The Federal Environmental • Climbing cutworms can be controlled, at least Pesticide Control Act of 1972 (Public Law 92-516) to some degree, by encircling the stems or in part prohibits pesticide application inconsistent trunks of trees and vines with a specially pre­ with its labeling, meaning that a pesticide cannot be pared, very thick and sticky substance. used unless it is registered for the specific pest on the specific plant. • Mechanical barriers, such as tin cans with both Insecticide label clearances are subject to change ends removed, placed around transplants offer and changes may have occurred since this publication some protection against cutworms. was printed. The pesticide USER is always respon­ sible for the effects of pesticide residues on his own Controlling Cutworms with Insecticides plants as well as problems caused by drift from his Treat soils infested with cutworms before any property to other properties or plants. seeds or transplants are placed in the garden. Table 1 All insecticides are poisonous and require careful lists suggested insecticides for preplant soil treatment. handling. Ifinsecticides contact the skin, remove the residue immediately by washing with soap and water. Table 1. Preplant soil treatment for cutworm control in the home garden. Store insecticides in a safe place out of reach of Dosage small children and irresponsible persons. Keep mate­ for 1,000 rials in their original, properly labeled containers, Insecticide Formulation sq. ft.' Vegetables away from human food or animal feed and away from Diazinon 79.4% E.C.2 6 fl. oz. in Cabbage, carrots, fire hazards. (Spectracide®) 3 gal. water corn, lettuce, peas, pole beans, rad­ Information prOVided here is for educational purposes ishes, red beets, only. Referenc;e to commercial products or trade names snap beans, toma­ is made with the understanding that no discrimination is toes, turnips intended and no endorsement by the Cooperative Exten­ 'Apply to soil surface and incorporate to a depth of 4 to 6 inches. sion Service is implied. 2E.C. = emulsifiable concentrate (mix with water before applying). Educational programs conducted by the Texas Agricultural Extension Service serve people ofall ages regardless ofsocio-economic level, race, color, sex, religion or national origin. Cooperative Extension Work in Agriculture and Home Economics, The Texas A&M University System and the United States Department of Agriculture cooperating. Distributed in furtherance of the Acts of Congress of May 8, 1914, as amended, and June 30, 1914. 20M-12-76 HORT.