IDENTIFICATION OF MEALYBUG-(HOMOPRERA, PSEUDOCOCEIDAE) RESISTANT TURF-TYPE BUFFALOGRASS GERMPLASM

Two species of mealybugs, Tridiscus sporoboli (Cockerell) and Trionymu s sp., have emerged as potentially serious pests of turf-type buffalog rass, Buchloe dactyloides (Nuttall) Engelmann. Sixty-two buffalograss selections were screened for resistance to these mealybugs in 4 greenh ouse trials. Using a 1-6 rating scale (1 = no signs of mealybugs, 6 = >75% of tillers infested), 'Prairie' and '609' showed high levels of r esistance to mealybugs, whereas several experimental selections. inclu ding 90-157, 84-512 and 84-412, exhibited moderate resistance. Most se lections were moderately susceptible, and 85-97 was highly susceptible with almost every tiller infested and plants near death. In field tes ts, mealybug infestations were highly variable, both within and among plots. However, in most cases, selections evaluated in the field showe d 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.