(Order: Lepidoptera, Family: Pyralidae, Evergestis rimosalis (Guenée))
Cross-striped cabbageworm late instar.
Adult: The adult has a wingspan of around 25 mm, so it is larger than the diamondback moth but smaller than a cabbage looper moth. Forewings are straw-colored with olive to purplish-brown markings and transverse lines and hindwings are whitish with a dark margin.
Immature stages: The eggs are laid in small clusters (3-25) underneath leaves and are 1.2 mm x 0.9 mm each.
Larvae develop through 4 instars. The last instar is 15-17 mm long and has a bluish-gray coloring along the back with numerous transverse black bands (hence “cross-striped”).
Life cycle: The duration time from egg to adult ranges from 18 days under warm conditions (35°C) to two months under cool conditions (20°C). The egg takes 2-12 days to hatch (warm and cool temperatures, respectively), larval development is 2-3 weeks and the pupal stage takes 9-11 days. Newly emerged adults take 3-6 days to begin laying eggs and then lay eggs over the next two weeks. Adults live only 20 days (as little as a week under warm conditions).
Seasonal distribution: In the mountains and Piedmont areas of northern Georgia this pest is commonly encountered, but has not been seen in the southern part of the State, likely due to its low tolerance for hot weather.
Cross-striped cabbageworm early instars
and leaf damage.
Damage to Crop: Damage to cole crops is similar to that of other Lepidoptera larvae, with holes or more extensive defoliation of young and mature leaves. Also, larvae can feed on the outside of the head or burrow into the developing head of cabbage.
Management: Generally, control of other Lepidoptera with traditional insecticides results in adequate control of this pest, but check labeling of newer insecticides. Also, check with the Cooperative Extension Service for current efficacy data. Scout weekly to twice weekly to determine if a 0.3 larvae/plant threshold has been reached and, if so, treat with an effective insecticide spray. Inspect for beneficial natural enemies, specifically parasitoids wasps in the genus Costesia, and do not count these larvae in the threshold above. Use Bacillus thuringiensis insecticide sprays early in the season to increase the opportunity for parasitism.
Prepared by Dr. Alton “Stormy” Sparks, Jr. and Dr. David G. Riley - University of Georgia