Influence of Weather Conditions on Aphid Population Density, Viral Symptoms Incidences, and Yield of Pepper (Capsicum spp.)

Abstract

SUMMARY The influence of weather factors (such as rainfall, relative humidity and temperature on viral symptom incidence, severity, aphid population density, and yield of hot pepper 'Atarodo' (Capsicum annuum L.) were investigated. Pepper seedlings were raised in the nursery and at 6 weeks old were transplanted on the field in a Randomized Complete Block Design (RCBD) at the College of Plant Science and Crop Production (COLPLANT) Teaching and Research Farm, Federal University of Agriculture, Abeokuta (FUNAAB). Weekly assessments were carried out from 2 to 6 weeks after transplanting (WAT) on incidence of viral symptoms and severity, aphid population density, and fruit yield. Concurrent agro-meteorological data on ambient ecology were obtained from the metrological station in FUNAAB. Aphid counts were square root transformed (√(X+0.5)) prior to statistical analysis. All data collected were subjected to analysis of variance (ANOVA), with significant means separated by least significant difference (LSD) test at P ≤ 0.05. Results revealed strong negative correlations between rainfall and both disease incidence and aphid populations in the first (r = -0.68; r = - 0.70) and second trial (r= -0.41; r = - 0.60) respectively, while temperature and humidity showed no significant effects. Disease incidence was inversely correlated with yield in both first and second trials (r = -0.97; r = -0.88), and similar trends were observed for disease severity (r = -0.92; r = -0.93). These findings highlight rainfall as a critical ecological factor suppressing aphid populations and viral disease incidence, thereby enhancing pepper productivity. The study emphasizes how crucial it is to incorporate weather-based forecasts into long-term disease control plans for pepper production.