Beet Armyworm Spodoptera exigua: Emerging Threat to Onion Production

Beet armyworm Spodoptera exigua Hubner (Lepidoptera: Noctuidae), hitherto a minor pest, had already taken a heavy toll on onion production. Regular monitoring of onion during 2017, for the S. exigua occurrence, revealed severe defoliation by this pest at the experimental farm in ICAR-DOGR, Pune. During the first appearance, about 44.72% plants were damaged with lesser feeding injury, while at the later stage the damage raised up to 81.90%. About 5–8 larvae/leaf fold and 3–4 larvae in an umbel were recorded at peak infestation. Severely infested plots registered with 10–12% damaged bulb after harvest. Overall mean plant damage ranged from 70.0 to 81.90% in some popular rabi onion varieties. However, the damage percentage does not differ significantly among the cultivated varieties which clearly denote the susceptibility of all these varieties. In the coming years, it will undoubtedly be a big problem for all states where onion is an important crop. Hence, much attention is needed, especially on pest bio-ecology in the onion ecosystem, scope of present IPM strategies employed for managing other major pest, bio-control potential and identification of safer insecticides for effective management to avoid yield loss.