Chemical control of Helicoverpa armigera (Hubner) (Lepidoptera; Noctuidae) in tobacco for seed production

Helicoverpa armigera (Hubner) (Lepidoptera; Noctuidae) is a pest of paramount important for tobacco seed production due to its feeding preference to seed capsules. For the purpose of assessing the potential of a chemical strategy addressed to H. armigera egg and neonate larvae, we test compounds belonging to different groups (chlorantraniliprole, emamectin benzoate, metaflumizon and methoxyfenozide). In this order their ovicidal and neonate larval toxicity have been established under laboratory conditions. Under field conditions their biological efficiency has also been assessed by controlling the extent of the damages caused to the tobacco seed capsules. We conducted two insecticidal treatments based on pheromone monitoring data. We have placed one pheromone trap per 0.5 ha to monitor seasonal pest flight activity. Depending on the extent of influence on the embryo, moderate eggs mortality rate demonstrate emamectin benzoate, chlorantraniliprole, methoxyfenozide and low egg mortality achieves metaflumizone. All tested chemical compounds provoke significantly high neonate larval mortality rates but no substantial differences were found in their effects. In the field all tested compounds significantly decreased extent of damaged compared with the control sample but no significant differences were found in their effects. The lowest number of damaged capsules was detected when applying emamectin benzoate followed by chlorantraniliprol, metaflumizone and methoxifenozide. The tested pest strategy points to H. armigera eggs and neonate larva gives opportunity to use combined ovicidal and larvicidal efficacy of the tested chemical components and successfully preserve seed capsules from damages.