Diamondback moth numbers can again increase in mid fall through early winter, but such an increase is a poor indicator of activity for the remainder of the leafy vegetable season. Diamondback moth begins to build on winter weeds such as mustard before moving into the green, red and asian cabbages grown predominately during winter and early spring seasons. This is probably due to near year round asian cabbage production and oversummering on watercress. Counts rarely reach over 50 per wk and frequently range from 0 to 5. They can be a serious pest of leafy vegetable crops.
Counts tend to be higher in areas where broccoli, cauliflower and cabbage are grown year round.
While corn earworm is primarily a pest of sweet corn in the EAA, pheromone trap counts of the insect do not necessarily correspond with the corn season. In 1990 we experienced a great increase in counts to over 250 per week in mid July, but the numbers were back down below 5 per wk by the time the corn season started. This pest can be found in most seasons in most fields, but is considered much less important than fall armyworm in EAA corn. Trap counts during the last three years have never exceeded 5 per wk, even during the height of the corn season.