Assessment of Pest Incidence and Associated Natural Enemies in Cauliflower Agro-Ecosystem of Muzaffarpur, Bihar, India

A roving survey was conducted during the cropping periods of 2021-22 and 2022-23 to study the seasonal incidence of major insect pests and their natural enemies in cauliflower ecosystems. Distinct temporal variations in pest population and activity of biological control agents was found throughout the cropping season. Tobacco caterpillar (Spodoptera litura), diamondback moth (Plutella xylostella) and aphids (Brevicoryne brassicae) were the predominant species found to cause considerable damage to cauliflower. The incidence of tobacco caterpillar initiated during the first fortnight of July and reached peak infestation during the second fortnight of October in both cropping seasons. The population of diamondback moth appeared during the second fortnight of August and reached maximum density during early October, with a secondary peak during March. Aphids persisted for a longer period and reached peak populations during the second fortnight of February. Several natural enemies were observed to regulate pest populations in the ecosystem. The larval parasitoid Bracon species was associated with tobacco caterpillar, showing peak parasitization during early October. The larval parasitoid Cotesia plutellae and the larval-pupal parasitoid Oomyzus sokolowskii were found attacking diamondback moth, with highest activity during October and March. Predatory coccinellids such as Coccinella septempunctata and syrphid larvae (Syrphidae) were identified as important predators of aphids. Their population increased during late winter and reached peak abundance during March, coinciding with higher aphid populations. Overall, a strong synchronization was found between pest incidence and the activity of natural enemies, highlighting their potential role in the natural regulation of pest populations in the cauliflower ecosystem.