Nonfruiting host tree volatile blends: Novel attractants for the plum curculio (Coleoptera: Curculionidae)

Abstract

We evaluated the attractiveness of novel synthetic host plant volatiles alone and in combination with the synthetic aggregation pheromone, grandisoic acid (GA), to overwintered adult plum curculio, Conotrachelus nenuphar (Herbst) (Coleoptera: Curculionidae) in association with black masonite pyramid traps deployed in an unsprayed apple orchard in 2003 and 2004. Synthetic host plant volatiles evaluated included (1) those identified from foliar and woody tissues of a nonfruiting Stanley plum tree (6-Tree) or the two major components (2-Tree); (2) those identified from Stanley plum fruit (7-Plum) or two components eliciting positive GC-EAD response from plum curculios (2-Plum); and (3) benzaldehyde formulated into rubber septa and replaced weekly [Ben (s)] or dispensed into polyethylene vials and replaced weekly [Ben (r)], not replaced [Ben (nr)], and formulated with 10% 1,2,4-trichlorobenzene and not replaced [Ben (TCB)]. In 2003, the greatest numbers of plum curculios were captured in traps baited with 6-Tree + GA and Ben (TCB) + GA, with responses to these baits significantly greater than responses to unbaited control traps. In 2004, the greatest number of plum curculios was captured in traps baited with 6-Tree(h) (high release rate dispenser) + Ben (TCB) + GA, with response to this bait significantly greater than responses to unbaited traps. Combined results indicate that volatiles released by foliar and woody tissues of plum are at least as attractive as the single fruit-based attractant, benzaldehyde, when combined with GA and point toward more competitive attractants for plum curculio based on multiple component blends of volatiles released by the entire tree.