Evaluation of the codling moth granulovirus and spinosad for codling moth control and impact on non-target species in pear orchards

摘要

We compared the efficacy of a commercial preparation of the codling moth, Cydia pomonella L., granulovirus, CpGV (Cyd-X) and spinosad (Entrust) at operational rates for codling moth control in 2004 and 2005. Concurrently we monitored the impact of treatments on populations of non-target arthropods. Spinosad was effective at protecting fruit, with ≦1.6% codling moth injury in experimental plots, compared with up to 37% injury in the untreated plots at harvest. Mid-season outbreaks of the pear psylla, Cacopsylla pyricola Forster, were also reduced in spinosad plots. Spinosad was safe for several predators, notably the psylla predator Deraeocoris brevis Uhler, but reduced the abundance of hymenopteran parasitoids by 24% and 40% and non-target Diptera by 49% and 35%, respectively in 2004 and 2005. We found no evidence that spinosad disrupted natural control leading to increased densities of secondary pests including aphids and phytophagous mites. CpGV was less effective than spinosad at protecting fruit, with percentage of fruits attacked similar to controls, but killed the majority (67–71%) of neonate coding moth larvae and did not harm non-target species. Additional observations were conducted in commercial orchards (mixed pear and apple) where CpGV and spinosad were used operationally against existing codling moth infestations. In pear, two spray programs applied in replicated 0.4 ha blocks (i.e. CpGV followed by spinosad against the first and second larval generations, respectively and vice versa) reduced fruit injury at harvest and decreased orchard pheromone monitoring trap catches by 74% over two years. In apple, CpGV was less effective at protecting fruit in the first larval generation compared with spinosad, although population suppression was effective early in the season. Spinosad caused no disruptions of beneficial species or secondary pest outbreaks were observed in the commercial orchards. Our results suggest CpGV and spinosad can be effectively used in integrated pest management for codling moth.