Plant Phenology-related Shifts in Color Preferences of Epicometis ( Tropinota ) Hirta (coleoptera: Scarabaeidae: Cetoniinae) Adults - Key to Effective Population Monitoring and Suppression

The study was conducted to elucidate the possibility that a shift in color preferences of adults of the apple blossom beetle, Epicometis hirta, occurs sometime after the end of overwintering and the onset blooming of Prunus spp. trees and between the termination of blooming and the death of the adults. Such information is needed to choose the best color of the traps used for the detection, monitoring and suppression of this major pest. In a randomized complete block experiment with 9 replicates at 3 different cherry orchard sites in Turkey, blocks of 11 differently colored traps each ere operated and serviced daily in cherry orchards from the end of hibernation of E. hirta the adults disappeared at the end of the season. The numbers of adult beetles captured in each of the 11 differently colored traps in each block were recorded daily. According to ANOVA and the Tukey’s test ( P < 0.01), significantly the largest numbers of E. hirta were sampled by floral white-colored traps in both the prebloom (experiment I-749 individuals, n = 38) and post-bloom (experiment III-263 individuals, n = 12) periods. However during the bloom period significantly the largest numbers of E. hirta were sampled by the light sky-blue-colored traps (experiment II-715 individuals, n = 30). The effect of the color and block on population of E. hirta was tested by univariate analysis of variance; and only color effect variation was found statistically significant. Likewise the results of cluster analysis showed that floral white-colored traps were more attractive for E. hirta than traps of any other color during the pre-bloom and post-bloom periods; whereas, light sky-blue colored traps were the most attractive for E. hirta during the bloom period. These data clearly demonstrate the color preference of E. hirta shifted from floral white before the cherry trees bloomed to light sky-blue during the bloom period and back to floral white during the postbloom period. These shifts may be an adaptation to the different host plant species that are predominant during different periods of the growing season. Currently some growers in Turkey control E. hirta during the cherry bloom period by intensive trapping with light sky-blue traps. However these data suggest that the control effort should be shifted to the prebloom period with intensive trapping by floral white traps.