Aphids are among the most destructive insect pests of wheat, with their population dynamics strongly influenced by host genotype, sowing time, and prevailing environmental conditions. This study evaluated aphid infestation across seven sowing dates and 12 wheat genotypes, evaluating relationship with natural enemies and weather factors with a goal of identifying sowing dates and genotypes associated with low aphid density. Seasonal mean aphid density differed significantly among genotypes for each sowing date. Of the 12 genotypes of wheat studied, two were highly susceptible and two consistently showed lower infestation. Aphid outbreaks peaked between 14 and 27 February, with maximum populations recorded on 20 and 27 February across several genotypes. Natural enemies such as Coccinellids, Chrysopids, Syrphids, and parasitoids displayed significant positive associations with aphid abundance, suggesting they are able to track cues to find prey, and may play a regulatory role. Abiotic factors were strongly predictive of infestation: averaging across all genotypes of wheat, aphid abundance decreased with temperature, with temperature alone explaining 73.5% of the variation in abundance. Aphid abundance also decreased with hours of daylight (explaining an additional 14.1% of the variation in abundance). These findings demonstrate that aphid population dynamics in wheat are genotype-specific and environmentally driven, with mid-to-late February identified as the most critical infestation window. Selecting resistant/tolerant genotypes, adjusting sowing dates, and leveraging the role of natural enemies provide a sustainable pathway for aphid management. These insights are vital for refining integrated pest management strategies under changing climatic conditions.

Understanding predator-prey dynamics is pivotal for advancing sustainable pest management strategies. This study examined the functional response of Harmonia axyridis across six developmental stages when preying upon the eggs of two destructive lepidopteran pests including Spodoptera litura and Spodoptera frugiperda. Using logistic regression and Holling’s disc equation, a clear Type II functional response was observed across all stages except first instars, indicating a density-dependent predation pattern constrained by handling time at higher prey densities. Adult females consistently emerged as the most potent predators, demonstrating the highest effectiveness of predation (1.591 on S. litura; 1.736 on S. frugiperda) and maximum predation rates (113.7 and 120.9 eggs, respectively). Adult males and fourth instar larvae also showed high predation capacities, with maximum consumption nearing 99 and 95 eggs. In contrast, first instars exhibited minimal predatory potential (effectiveness <0.017; maximum consumption <10 eggs), highlighting the critical role of developmental maturity in predation performance. Notably, predation on S. frugiperda eggs slightly surpassed that on S. litura, suggesting host-specific traits may modulate predator efficiency. The functional response curves confirmed a classic decelerating intake rate at high prey densities, characteristic of Type II predators. These findings affirm the high consumptive potential of H. axyridis, particularly adult females, as efficient natural enemies against Spodoptera spp. eggs, and provide actionable insights for their integration into targeted, stage-specific biological control programs.

Pieris brassicae (Linnaeus, 1758) (Lepidoptera: Pieridae), commonly known as the cabbage butterfly, is a major herbivorous pest causing significant damage to Brassica crops, which are widely cultivated for edible parts and economic uses such as oilseed production. Conventional chemical-based pest control methods pose risks to environmental and human health, prompting interest in sustainable alternatives like biological control using parasitoids. This study evaluated crop damage by P. brassicae larvae and the potential of the larval parasitoid Cotesia vestalis (Haliday, 1834) (Hymenoptera: Braconidae) in managing pest populations. Larvae and fertilized eggs of P. brassicae were collected and reared on four host diets (cabbage, cauliflower, turnip, and generic brassica) under controlled laboratory conditions. Larval growth, feeding behavior, and development were assessed, along with a feeding index for dietary efficiency. Parasitisation was introduced by exposing larvae to adult C. vestalis, and host-parasitoid interactions were statistically analyzed using one-way ANOVA and regression models. Results revealed that larvae had the highest feeding preference and weight gain on brassica, while turnip-fed larvae consumed the least. Parasitisation by C. vestalis significantly suppressed larval development, with a strong correlation between parasitisation rates and reduced host fitness. These findings highlight C. vestalis as a promising biological control agent for P. brassicae, offering an effective and eco-friendly alternative to chemical pesticides. Further research should focus on optimizing C. vestalis mass-rearing protocols and release strategies tailored to diverse Brassica cropping systems to promote sustainable pest management.