Impact of the zoophytophagous predator Engytatus varians (Hemiptera: Miridae) on Bactericera cockerelli (Hemiptera: Triozidae) control

Engytatus varians (Distant) (Hemiptera: Miridae), a polyphagous predator that is widely distributed, has recently been documented for the first time in Mexico, feeding on nymphs of the very detrimental pest of several solanaceous crops Bactericera cockerelli (Sulc.) (Hemiptera: Triozidae). The predation of this mirid was evaluated in a greenhouse in 7 m(2) cages containing tomato (Solanum lycopersicum Miller) plants for 12 weeks. Two release rates, 1 and 4 adults of E. varians (Ev)/plant, were studied and compared to the control (0 Ev/plant). An 80 to 90% reduction in both nymphs and adults of B. cockerelli occurred when 1 or 4 adults of Ev/plant were released irrespective of the pest life stage. The cumulative number of E. varians nymphs and adults per day was significantly higher in the treatments than in the control (30 and 3, respectively). On the other hand, due to its zoophytophagous habits, E. varians can feed on tomato plants and cause necrotic rings on the leaves; therefore, this type of injury was also recorded. The number of necrotic rings/leaf was inversely proportional to prey presence, but no significant differences were observed between the treatments. Our results point to E. varians being able to establish and control B. cockerelli populations under greenhouse conditions, without causing significant damage to tomato plants. The potential use of this predator as a biological control agent of B. cockerelli is discussed.