International Journal of Environment and Climate Change

Background: Cocoa cultivation in Andhra Pradesh has expanded rapidly, and insect pests are now a leading biotic constraint on tree vigour and pod yield, with their occurrence fluctuating by season and prevailing weather.

Aims: To quantify seasonal incidence of major cocoa insect pests, test the consistency of seasonal patterns across years, and relate incidence to weather parameters.

Study Design: Three-year longitudinal roving survey from February 2023 to January 2026. Place and Duration of Study: Twelve farmer-managed cocoa farms, Eluru district, Andhra Pradesh, India (16°42′N, 81°06′E); 2023 to 2025.

Methodology: Monthly pest incidence was recorded from 100 unsprayed trees per farm. Seasons were defined as summer (February–May), monsoon (June–September) and post-monsoon (October–January). The seasonal and annual incidence of major pests in the cocoa agroecosystem was assessed. The consistency of seasonal incidence across years, the influence of the year × season interaction, and the influence of weather parameters on seasonal incidence were also statistically analysed.

Results: Conogethes punctiferalis (husk borer), Indarbela sp. (bark-eating caterpillar), Planococcus citri (citrus mealybug) and Pseudococcus longispinus (long-tailed mealybugs) were dominant in all years. Peak incidence of lepidopteran pests declined progressively, with husk borer infestation decreasing from 68.38 ± 5.55% (2023-24) to 23.02 ± 3.18% (2025-26), and bark-eating caterpillar incidence from 51.81% to 8.38%. Mealybug incidence peaked post-monsoon during the first two survey years (citrus mealybug 34.79% and 32.73%) but shifted to summer in 2025-26 (35.79%). Year × season interactions were highly significant (p < 0.01) for all four pests. Lepidopteran pests were more strongly associated with relative humidity (r = −0.46 to −0.64) than with temperature (r = 0.41–0.42). Citrus mealybug correlated negatively with rainfall (r = −0.43, p = 0.01), while long-tailed mealybug showed no significant weather association.

Conclusion: The seasonality of lepidopteran pests was directionally stable, consistently peaking in summer with declining amplitude across years, whereas both mealybug species shifted their peak incidence from post-monsoon to summer in 2025-26, a directional change not fully explained by the weather associations tested here. Seasonal structuring can therefore vary in both amplitude and direction, limiting calendar-fixed control. Monitoring should focus on the summer months for husk borers and bark-eating caterpillars, and the post-monsoon period for mealybugs. Allowance should be made for seasonal shifts in years when the weather is inconsistent.