Using Odor-Baited Trap Trees as Sentinels to Monitor Plum Curculio (Coleoptera: Curculionidae) in Apple Orchards

Abstract

In commercial orchards in Massachusetts in 2003, we conducted experiments aimed at developing guidelines for use of perimeter-row trap trees baited with grandisoic acid plus benzaldehyde as sentinels in a practical approach to determining need and timing of insecticide applications against overwintered plum curculios, Conotrachelus nenuphar (Herbst). Evaluations were based on percentages of sampled fruit injured by plum curculio. Trap trees baited with grandisoic acid released at approximately 1 mg/d plus benzaldehyde released at approximately 40 mg/d performed as well as or better than trap trees baited with greater or lesser amounts of these attractants in combination. The distance over which a trap tree baited with such odor was effective in aggregating damage to fruit extended to at least 31-33 m (maximum evaluated) along a perimeter row. Trap trees at corners of orchard blocks were as effective as perimeter-row trap trees midway between corner trees. Within the canopy of a trap tree, damage did not tend significantly to be localized in the vicinity of the odor source but tended to be rather evenly distributed among various sectors of the canopy. Finally, among three candidate thresholds evaluated as a trigger for insecticide application, a threshold of one freshly injured fruit proved better than thresholds of two or four freshly injured fruit out of 50 fruit sampled on a trap tree in assuring that orchard-wide damage would remain below a preset economic injury level of 1%. Our findings lead us to suggest that after a whole-orchard application of insecticide to apple trees in Massachusetts orchards shortly after petal fall, subsequent applications of insecticide against plum curculio can be confined to peripheral-row trees and be driven by a provisional threshold of one freshly injured fruit out of 50 fruit sampled on a perimeter-row trap tree baited with the above-mentioned odor.

Impact of the Invasive Brown Marmorated Stink Bug in North America and Europe: History, Biology, Ecology, and Management

“…First, plots were likely too small because of trap spillover. Indeed, traps, particularly those baited with aggregation pheromones, often result in increased plant injury near the trap (123), as pests are attracted to and arrive near the baited trap but remain outside the trap itself (134). BMSB aggregates within 2.5 m of traps baited with pheromonal stimuli, with "trap spillover" estimated to be less than 10% (104).…”

Visual Cues and Capture Mechanisms Associated with Traps for Plum Curculio (Coleoptera: Curculiondae)

“…This technique has been enhanced by creating trap trees'. Apple trees are baited with synthetic volatile dispensers of plum curculio aggregation pheromone and benzaldehyde which result in an aggregation of oviposition injury in baited tree canopies (Prokopy et al 2003(Prokopy et al , 2004.…”

Establishing abiotic and biotic factors necessary for reliable male pheromone production and attraction to pheromones by female plum curculiosConotrachelus nenuphar(Coleoptera: Curculionidae)

“…Differences related to concentrations of lures containing GA have previously been shown to be an important factor regarding PC behaviour. For example, field studies demonstrated no an increase in PC attraction towards trap trees baited with twice the attractive amount of GA (Prokopy et al 2004). Concentration-dependent behavioural responses have also been observed in the cigarette beetle (Coffelt and Burkolder 1972), the boll weevil (Hardee et al 1974), and the Asian palm weevil (Hallett et al 1999).…”

“…High humidity and temperatures in the presence of suitable fruit should also elicit a good pheromone production based on the natural behaviour of the insect, which exhibits a greater activity under these conditions (Garman and Zappe 1929;Smith and Flessel 1968;Butkewich and Prokopy 1993;Chouinard et al 1993Chouinard et al , 1994. It is likely that PCs respond to low doses of GA , since high doses do not result in an increased attraction (Prokopy et al 2004). Plum curculios should also respond more strongly to mixtures that contain greater amounts of the positive enantiomer, since this is what is produced naturally (Eller and Bartelt 1996).…”