Field and Laboratory Efficacy of Low-Impact Commercial Products in Preventing Olive Fruit Fly, Bactrocera oleae, Infestation.

Elissa Daher,Nicola Cinosi,Elena Chierici,Eric Conti,Franco Famiani,Gabriele Rondoni

doi:10.3390/insects13020213

Abstract

Simple SummaryThe adoption of sustainable methods for herbivore pest control has become mandatory in Europe, with the EU directive 128/09. Since then, stringent evaluation protocols have been applied to insecticides and several molecules (that are suspected to be unsafe for the environment or human health) have been banned. Hence, the evaluation of sustainable methods, e.g., preventive tools based on the manipulation of pest behaviour, must be considered. Using field and laboratory assays, we tested the efficacy of different products in preventing infestation of a key pest of olive orchards, the olive fruit fly Bactrocera oleae. Our findings may be useful for the development of control strategies in integrated pest management (IPM) and organic agriculture.The olive fruit fly, Bactrocera oleae, is the key pest of olive trees in several areas of the world. Given the need for the development of sustainable control methods, preventive tools, based on the manipulation of pest behaviour, must be considered. Here, under field and laboratory conditions, we tested the efficacy of different products in preventing B. oleae infestation. A field trial was conducted, from July to November 2020, in an olive orchard located in Central Italy. A table olive variety was selected and sprayed with rock powder, propolis, the mixture of both, copper oxychloride, or water (control). All treatments, except propolis, caused a reduction of B. oleae oviposition in olives, compared to the control. The mixture allowed the strongest reduction of fly infestation throughout the season, suggesting a synergistic effect. Behavioural no-choice assays were conducted to better understand the effects of treatments on B. oleae females. Compared to the control, females showed a lower preference for the central area of an arena containing an olive twig bearing two olive fruits, fully developed, but still green, treated with rock powder, plus propolis mixture. For all treatments, B. oleae showed lower oviposition events, suggesting deterrence to oviposition. Our results indicate that the tested products may have value against B. oleae, within integrated pest management (IPM) and organic agriculture.

Highlights

The growing consciousness on the side effects of chemicals used for plant protection has resulted in increased research of more environment-friendly approaches, which encompass the manipulation of pest behaviour [45]
The field experiment results reported here demonstrate the role of the rock powder, especially when combined with propolis, in reducing fruit infestation by B. oleae
In spite of that, during the whole data collection period, i.e., from 12 days after first treatments to 11 weeks later, the branches treated with the rock powder and propolis mixture showed lower levels of infestation, compared to those of the other treatments

Summary

Introduction

Fruit flies, belonging to the family Tephritidae, include key pests of economically important fruit trees and vegetables [1]. Among the 932 species described to date [2], the most harmful ones are included in the genera Bactrocera Macquart, Ceratitis Macleay, and Rhagoletis Loew [3]. Economic damage is caused by larval feeding inside the fruits. Eggs are deposited under the fruit surface and larvae feed on the mesocarp causing fruit drop or a strong decline in fruit quality [4]. Many strategies have been deployed to manage these pests. Since the last four decades, organophosphate insecticides, especially as cover sprays, 4.0/)

Methods

Results

Conclusion