The field skipper, Atalopedes campestris, is a sporadic pest of bermudagrass hay fields in northeastern Texas. Damaging infestations are often localized, limited to one or two counties, and are characterized by very large numbers of larvae, up t o 50 or more per square yard. Larvae consume the leaves, leaving only stems which lowers forage quality and tonnage.

The adult stage is called a skipper butterfly, so named for their very rapid, direct and often short flights. These butterflies appear to "skip" across a field as they dart from place to place. There are about 250 different species of skippers in North America. Of the eleven species that feed on bermudagrass, only the field skipper and the fiery skipper, Hylephila phyleus, are economically important. The fiery skipper is an important turf pest in Hawaii and California. The field skipper is common throughout the southern U.S. south to Brazil and Ecuador.

The field skipper was first reported as an economic pest in 1955 when infestations developed in northwestern Arkansas. Bermudagrass pastures were consumed and large numbers (50-75 per square yard) of caterpillars moved across roads and into yards seeking food. A similar outbreak occurred in Hopkins County, Texas in 1985, although this pest had caused some damage in previous years in this county.

In 1989, field skipper caterpillars caused extensive damage to some bermudagrass hay fields in parts of Kaufman and adjacent Henderson County. As in earlier reports, caterpillar numbers and damage were the greatest in mid-July. The conditions that lead to outbreaks of the field skipper are not known.

LIFE CYCLE

The adult stage of the field skipper is a butterfly (Fig. 1). Males are orange- brown with a single large black spot on each forewing. Females are dark brown with a few silver and orange spots on the wings. The wing span is about one inch. The butterf lies are commonly seen along wooded rows and weedy areas where they visit flowers for food. They probably live several weeks.

Field skippers are known to lay eggs on bermudagrass and St. Augustine grass. Eggs are very small, less than 1/20 inch in diameter, and laid singly on dry grass blades. Eggs hatch in 4-5 days and the tiny larvae begin feeding on grass leaves. Young cat erpillars are whitish with a tint of green and a black head. Mature caterpillars are dark, olive-green with a black head. The body is constricted just behind the neck, making the head appear very large. The body is smooth, tapered to the front and back, and lacks hairs or spines. Two or three white, chalky spots are found on the underside between the back legs of full grown caterpillars.

Caterpillars mature in three to four weeks and enter the pupal stage. Pieces of leaves and soil may be wrapped with silk around the pupa which are found on the ground. The adult or butterfly emerges from the pupa in about 10 days.

Development form egg to adult requires about 40 days, depending upon temperature. There are probably three generations each year. The insect overwinters as a larva of pupa.

DAMAGE

Field skippers feed primarily on bermudagrass and St. Augustine grass, but will eat other grasses when forced. Caterpillars consume the leaves, leaving the stems. Field skippers caterpillars construct silken shelters by tying together grass stems about midway up the plants. Pieces of chewed leaves and caterpillar droppings are found in the silk shelters.

Entire fields are commonly infested. Once the grass is consumed, larvae may crawl armyworm-style across roads and damage adjacent fields or lawns. Infestations are often first detected as masses of caterpillars crawl up buildings and attack lawns aroun d homes. As with other caterpillars, most of the feeding occurs during the last larval stages and hay fields and lawns can be quickly defoliated as larvae reach maturity.

CONTROL

Bermudagrass hay fields and meadows should be examined for skipper caterpillars beginning in late June and continuing through July. Because caterpillars feed within the canopy, infestations can go undetected unless the grass is carefully inspected. Loo k for bunches of grass stems tied together by silk shelters in which larvae feed. Each field should be inspected as infestations very a great deal even between adjacent fields.

Early harvest of infested fields will reduce hay loss. However, large numbers of caterpillars may survive after harvest and feed on regrowth. If cut fields do not green up normally and caterpillars are alive in the field, or if early cutting is not an option, an insecticide treatment may be necessary. Sevin\ (carbaryl) and malathion have been reported to provide control. Sevin 80S and Sevin XLR are labeled for pastures. Hay should not be cut or grazed for 14 days after application by ground equipment (aerially treated pastures may be grazed or cut for hay on day of treatmen t). Pastures treated with malathion can be harvested or grazed without delay after treatment.

Caterpillar numbers and damage are greatest in mid-July but although additional generations probably develop, caterpillars are often very difficult to find after July. Very large numbers of field skipper butterflies were present along wooded fence rows around bermudagrass hay fields in late July through August following the outbreak in Kaufman County in 1988. However, caterpillars could not be found after July and no subsequent infestations were observed. A very large outbreak in July followed by a near absence of a subsequent larval generation is without explanation but has been observed during other outbreaks in Texas and Arkansas.

Warren, L.O. and J.E. Roberts. 1956. A Hesperid, Atalopedes campestris (BVD.), as a pest of bermudagrass pastures. J. Kansas Entomol. Soc. 29: 139-141.

The information given herein is for educational purposes only. Reference to commercial products or trade names is made with the understanding that no discrimination is intended and no endorsement by the Cooperative Extension Service is implied.

Educational programs conducted by the Texas Agricultural Extension Service are open to all people without regard to race, color, sex, disability, religion, age or national origin.

1990

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Last modified: March 18, 1997 by Edgar Cross