Impact of climate change on distribution and severity of aphid infestations in brassica crops

Abstract:

Climate change, defined as a persistent shift in temperature and precipitation patterns over decades, is increasingly reshaping pest–crop dynamics in arid agriculture. This research examined how rising temperatures affected the distribution and severity of aphid (Brevicoryne brassicae and Lipaphis erysimi) infestations on brassica crops at the Hail Institute of Agricultural Sciences, Saudi Arabia, across three consecutive winter growing seasons (2020–21, 2021–22, 2022–23). Aphid population counts, species composition, and crop damage scores were recorded fortnightly at five temperature-differentiated micro-sites. Peak aphid densities occurred at 20–25 °C (mean 67.8 per plant), declining sharply above 30 °C (31.6 per plant) and collapsing beyond 35 °C (14.2 per plant). L. erysimi replaced B. brassicae as the dominant species at warmer sites. Aphid peak shifted 12–18 days earlier over the three seasons. The results indicate that continued warming will compress the aphid activity window but may intensify damage during the shortened peak.