The effect of emamectin benzoate on two parasitoids, Aphidius colemani Viereck (Hymenoptera: Braconidae) and Eretmocerus mundus Mercet (Hymenoptera: Aphelinidae), used in pepper greenhouses

P Bengochea,R Correia,M Cánovas,P Medina,E Viñuela,P Vega,M Gómez,F Amor,F García,F Budia,J A López

doi:10.5424/sjar/2012103-684-11

Abstract

Aphidius colemani Viereck and Eretmocerus mundus Mercet are two of the most representative parasitoids used as biological control agents (BCAs) primarily against aphids and whiteflies, respectively. The macrocyclic lactone emamectin benzoate (4”-deoxy-4”-methylamino-4”-epiavermectin B1 benzoate), an insecticide derived from the avermectin family of natural products, is being developed for controlling lepidopteran pests on a range of vegetable and other crops in Europe. The objective of this study was to determine the level of compatibility of the insecticide emamectin benzoate with A. colemani and Er. mundus, which are used in greenhouse vegetable production in southeastern Spain. Trials were conducted under commercial greenhouses to assess the effect of 1-, 3- and 7-day-old residues of emamectin benzoate at the highest recommended concentration (14.25 mg L-1) on the population dynamics of the parasitoids. A. colemani, although released at higher rates than those commercially used, only reached low densities (less than 1 adult per plant), without significant differences among control plots and those treated with the compound. On the contrary, a natural infestation by native Er. mundus occurred and this trial can be considered as a direct-spray trial. Neither adult population nor parasitism on emamectin benzoate treated plots differed significantly from the control. Therefore, emamectin benzoate residues did not diminish A. colemani population densities if applied 1 day before the introduction of the arthropod (exposure to 1-day old residues). Similarly, emamectin benzoate was compatible with Er. mundus if a direct spray application was used on developed populations.

Highlights

Tomatoes (Solanum lycopersicum L.) and sweet peppers (Capsicum annuum L.) are the two most important protected vegetable crops in the southeastern regions of Spain, Almería and Murcia (Urbaneja et al, 2007).Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae), a key pest of many crops throughout subtropical and tropical regions of the world, causes significant problems in protected agricultural systems in temperate regions (Naranjo, 2001)
The sweet potato whitefly is currently managed through integrated pest management (IPM) programmes based on the release of commercial biological control agents (BCAs)
The insect was released according to the original plans, this trial can be considered as a direct-spray trial in terms of the results and conclusions because insecticide applications were performed in the presence of the parasitoid

Summary

Introduction

Tomatoes (Solanum lycopersicum L.) and sweet peppers (Capsicum annuum L.) are the two most important protected vegetable crops in the southeastern regions of Spain, Almería and Murcia (Urbaneja et al, 2007). Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae), a key pest of many crops throughout subtropical and tropical regions of the world, causes significant problems in protected agricultural systems in temperate regions (Naranjo, 2001). The most successfully parasitoids used worldwide against B. tabaci belong to the aphelenid hymenopteran genera, Encarsia and Eretmocerus. Eretmocerus mundus Mercet (Hymenoptera: Aphelinidae) is effective against B. tabaci in the Mediterranean area (Calvo & Belda, 2006; Van der Blom, 2008; Van der Blom et al, 2008), where natural populations are abundant in insecticidetreated and untreated vegetable and ornamental crops (Stansly et al, 2005)

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