Economic survey to support control decision for old world bollworm on processing tomatoes

Nayara Cristina Magalhães Sousa,Antônio Williams Moita,Karla Fernanda Ayres De Souza Silva,Jorge Braz Torres,Miguel Michereff-Filho,Paloma Alves Silva

doi:10.1590/1678-992x-2019-0280

Nayara Cristina Magalhães Sousa, Antônio Williams Moita + Show 4 more

Open Access

https://doi.org/10.1590/1678-992x-2019-0280

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Abstract

ABSTRACT: Helicoverpa armigera (Hubner) regularly requires quick deployment of control practices due to its potential of causing yield loss of processing tomatoes. The monitoring of H. armigera adults using stick traps lured with sex pheromone was correlated to egg densities, larvae, and percentage of damaged fruits, aiming to subsidize control decisions only using the number of males caught in the traps since surveying pest stages or damaged fruits is laborious and costly. Surveys were carried out on 11 tomato fields (ca. 80 to 120 hectares each) for processing during the 2015 and 2016 crop seasons. The survey was initiated at the flowering stage with traps set up along the field borders 100 m distant each. Evaluations of adult male capture in the traps were conducted twice a week for 14 and 10 weeks during the 2015 and 2016 seasons, respectively. Simultaneously, 70 tomato plants were fully inspected for eggs, larvae, and damaged fruits per area using a rate of 10 plants per point of trap setting in each area. Overall capture of male moths correlated to subsequent eggs, larvae, and damaged fruits. Based on the outcome of the regression analysis between male moths captured and percentage of damaged fruits, the control decision is suggested when three to six male moths are captured per trap during one week. The monitoring of adults using pheromone traps help deploy chemical or biological control methods to restrain H. armigera population reaching economic threshold levels.

Highlights

The Old World bollworm, Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae), was recorded damaging various crops in Brazil in 2013 (Czepak et al, 2013; Specht et al, 2013)
Data from male moths captured per trap highlight the predominant period of H. armigera activity in processing tomato fields during two growing seasons
The fluctuation of H. armigera determined in this study used sex pheromone traps during two growing seasons in large commercial processing tomato fields and depicted variation in the number of male moths captured and their correlations with damaged fruits, thereby, showing the potential of pest infestation prediction and support for control tactics

Summary

Introduction

The Old World bollworm, Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae), was recorded damaging various crops in Brazil in 2013 (Czepak et al, 2013; Specht et al, 2013). Afterwards, there was a quick dispersion through several states in Brazil and across the South and Central American regions (Murúa et al, 2014; Kriticos et al, 2015; Castiglioni et al, 2016) It became a major issue for integrated pest management (IPM) already established, requiring new protocols for monitoring and spraying field crops. Adopting pest monitoring and considering the injury levels for making control decisions can optimize the mitigation of such problems In this context, the use of traps containing synthetic sex pheromone has been successfully applied to support control decisions (Ahmed and Khalique, 2002; Pal et al, 2014). According to Izquierdo (1996), traps with synthetic sex pheromone aim to obtain rapid information about the pest presence in the field crop, determine population fluctuation over time irrespective of the host crop phenology and within intercropping periods (Neves et al, 2018)

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