Identification of Mealybug- (Homoptera: Pseudococcidae) Resistant Turf-Type Buffalograss Germplasm

Two species of mealybugs, Tridiscus sporoboli (Cockerell) and Trionymus sp., have emerged as potentially serious pests of turf-type buffalograss, Buchloe dactyloides (Nuttall) Engelmann. Sixty-two buffalograss selections were screened for resistance to these mealybugs in 4 greenhouse trials. Using a 1-6 rating scale (1 = no signs of mealybugs, 6 = >75% of tillers infested), 'Prairie' and '609' showed high levels of resistance to mealybugs, whereas several experimental selections, including 90-157,84-512 and 84-412, exhibited moderate resistance. Most selections were moderately susceptible, and 85-97 was highly susceptible with almost every tiller infested and plants near death. In field tests, mealybug infestations were highly variable, both within and among plots. However, in most cases, selections evaluated in the field showed similar responses as in greenhouse trials. Pubescence was positively correlated with buffalograss susceptibility to mealybugs. A glabrous leaf surface is suggested as a possible mechanism of resistance.