Pre-Bloom Application of Petroleum Spray Oil for the Control of Green Apple Aphid, Aphis pomi DeGeer in Apple Orchards [Data]

The green apple aphid (Aphis pomi DeGeer) is a key early-season pest in apple orchards. Petroleum spray oils (PSOs), are routinely applied at the delayed dormant stage for managing pests like San José scale and European red mite. However, their impact on A. pomi has not been thoroughly evaluated. This study evaluated the ovicidal and larvicidal efficacy of PSOs (2% v/v) applied at the delayed dormant/green tip stage in apple orchards in Jammu and Kashmir, India. Laboratory and field assays demonstrated substantial suppression of egg hatch, with cumulative hatch reduced to 9.90 ± 0.57% (laboratory assay) and 9.62 ± 0.71% (field evaluation) in treated shoots compared to 46.91 ± 0.68% and 53.25 ± 3.25% in controls, respectively. Survival analyses revealed significantly higher mortality risk for treated eggs. Direct toxicity trials on nymphs showed mortality rates of 69.9 ± 1.95% in field conditions and >99% in lab dip assays by 5 days after treatment. Residual toxicity assays indicated cumulative mortality reaching 64.07 ± 2.74 % by 2 days post-exposure, confirming efficacy even after drying. Field trials further revealed that PSO significantly reduced bud infestation by A. pomi (5.22 ± 0.54%) compared to the untreated control (19.04 ± 2.34%), with enhanced suppression observed when combined with imidacloprid (0.29 ± 0.14%). These findings underscore the potential of PSO as both a standalone and synergistic agent in aphid management, particularly when integrated with systemic insecticides. This is the first detailed report on the ovicidal and larvicidal activity of PSOs against A. pomi, supporting its inclusion in sustainable, early-season integrated pest management programs.