Coleomegilla maculata, Coccinella septempunctata (Coleoptera: Coccinellidae), Chrysoperla carnea (Neuroptera: Chrysopidae), and Macrocentrus grandii (Hymenoptera: Braconidae) Trapped on Colored Sticky Traps in Corn Habitats

Behavioral responses of 4 species of natural enemies to 4 colors were examined by capturing adults on colored sticky cards placed at 2 locations (edge and interior) in corn, Zea mays L., fields. Cards were placed at 2 heights (1.8 and 0.3 m) in 1993 and in 2 habitats (sweet and field corn) in 1994, using a split-split plot design. Natural enemies studied included the coccinellids Coleomegilla maculata (DeGeer) and Coccinella septempunctata L., the chrysopid Chrysoperla carnea (Stephens), and Macrocentrus grandii Goidanich, a braconid larval parasitoid of Ostrinia nubilalis (Hübner). Compared with red, green, and white cards, yellow cards trapped greater numbers of all natural enemies, except C. carnea, which was trapped equally on cards of all 4 colors. Few significant interactions were observed between the effects of color and those of location and height or habitat, which are perhaps indicative of microhabitat preferences. Captures on cards provided information on abundance of each natural enemy species during different periods in the summer. It also revealed the pattern of adult flights of M. grandii, which is useful for determining whether its life cycle is synchronized with that of its host. The study suggests that, besides studying behavioral responses, color cards may be useful for monitoring natural enemy populations.