Resistance of oriental fruit moth (Lepidoptera: tortricidae) to insecticides in apple orchards in southern Brazil

Helena Cristina Da Silva De Assis,Rosangela Teixeira,Edson Chappuis,Lino Bittencourt Monteiro,Izonete Cristina Guiloski

doi:10.1590/0100-29452018608

Helena Cristina Da Silva De Assis, Rosangela Teixeira + Show 3 more

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https://doi.org/10.1590/0100-29452018608

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Abstract

Abstract Oriental fruit moth (Grapholita molesta) is the most important pest of apple orchards in Brazil. For many years, insecticides have been the only tool used for its control. The aim of this work was to characterize the management of apple orchards by the system for Assessment of Environment Impact of Agricultural Technology Innovations (AMBITEC-AGRO) and to relate it with the resistance status of G. molesta populations. Insecticide resistance was estimated by toxicology and enzymatic activities of glutathione S-transferase (GST), esterases (a-ß EST), and acetylcholinesterase (AChE). The phytosanitary strategies adopted by the four apple production orchards in southern Brazil were analyzed in: Vacaria (RS population), Fraiburgo (SC1 population), São Joaquim (SC2 population), and Porto Amazonas (PR population). Oriental fruit moth field populations were reared in laboratory for bioassays with chlorpyriphos, carbaryl, deltamethrin, and tebufenozide insecticides and were compared with a reference susceptible population. Larval mortality rates were recorded for seven days. GST, a-ß EST, and AChE assays were performed with third- and fourth-instar larvae. Results indicated that oriental fruit moth populations collected in Vacaria, Fraiburgo, and São Joaquim showed tolerance to carbaryl and chlorpyriphos, whereas the population collected in Porto Amazonas was more susceptible. SC2 and PR populations were more tolerant to deltamethrin, while RS and SC1 populations were more susceptible. No population was tolerant to tebufenozide. RS population showed the highest activity for AChE, GST, and a-EST. The findings of this study suggest that the AMBITEC-AGRO system was a suitable method to evaluate the phytosanitary activity of apple orchards and to relate it to the resistance status of G. molesta populations.

Highlights

Oriental fruit moth, Grapholita molesta (Busk, 1916) (Lepidoptera: Tortricidae), is the most important peach pest worldwide (SHEARER, USMANI, 2001; LLANOS; MARIN, 2004; TIMM et al, 2008)
The aim of this work was to characterize the management of apple orchards and to relate it with the resistance status of G. molesta populations collected in apple orchards in Southern Brazil that were exposed to four insecticides
São Joaquim orchard used more than two chemical groups for pest control, and in Porto Amazonas orchard, insecticides used were of one group during the first three years, but three groups were used on the two years

Summary

Introduction

Grapholita molesta (Busk, 1916) (Lepidoptera: Tortricidae), is the most important peach pest worldwide (SHEARER, USMANI, 2001; LLANOS; MARIN, 2004; TIMM et al, 2008). The same occurred in apple it was found in the eastern U.S in the 1990s (FELLAND; HULL, 1998; BERGH; ENGELMAN, 2001). The larvae attack the peach and apple fruits and, the damages are similar in both plant species (NATALE et al, 2003). Due to the high value of host crops and strict quality standards for domestic and export markets, there is a near zero tolerance regarding fruit damage. Chemical control plays a key role in the management of G. molesta, as well as of two other economic pests: Brazilian apple leafroller, Bonagota salubricola (Lepidoptera: Tortricidae) and South American fruit fly, Anastrepha fraterculus (Diptera: Tephritidae)

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