Bases para a tomada de decisão de controle de Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) em tomateiro para processamento industrial

Abstract

Tomato cropping is relevant worldwide and the fruits are commercialized as fresh food or for industrial processing. Pest infestation, however, reduces tomato yield with Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) considered as key insect pest of tomatoes, in special, in Brazil due to its recent record of introduction. The pest status is directly associated to the fruit damage. Thus, studies to determine yield losses and other information to help control decision are needed. The monitoring of H. armigera infesting 11 tomato fields for processing (80 to 120 hectares each) using traps lured with sex pheromone was carried out during 2015 and 2016 crop seasons. Further, the determination of crop losses during fruiting stage was done using field cages and artificial infestation with 2nd-instar larvae during 2017 and 2018. Adult moth fluctuation monitored with pheromone traps correlated positively with densities of eggs and larvae, and percentage of damaged fruits. Concerning the evaluation of losses for caged tomatoes plants there were significant relationship of damaged fruits with yield decrease. The economic threshold (ET) level varied from 1.23 to 3.08 larvae per linear meter of tomatoes in 2017 and 2018 trials, respectively. Based on the results of the percentage of damaged fruits accumulated as a function of the adults captured in a sex pheromone traps suggest decision to control H. armigera when catching 5 to 8 adults per trap accumulated per week. Thus, depending on control costs and yield value, the decision for recommending curative control against H. armigera larvae varies between 0.99 and 2.46 larvae per linear meter of plants for processing tomatoes.