Abundance of Tuta absoluta (Meyrick, 1917) and its natural enemies on tomato crops in greenhouses of different production modes (Azores, Portugal) (Lepidoptera: Gelechiidae)

Abstract

Tuta absoluta (Meyrick, 1917) (Lepidoptera: Gelechiidae) is a major pest of tomato (Solanum lycopersicum L.) crops produced in the Azorean greenhouses. Despite the major concerns, no systematic study is available to describe population dynamics of T. absoluta and its natural enemies. The objective of this study was to compare the abundance of the pest (eggs and larvae) and its native natural enemies, in greenhouses of tomato crops produced under different production modes (biological, traditional and intensive). A sampling program was carried out during 2020-2021 and two production seasons of spring-summer and fall-winter. The abundance of eggs and larvae of T. absoluta were higher in tomato crops in intensive production and lower in biological production mode. Infestations by eggs and larvae were higher in spring-summer seasons. The natural enemies recorded were Macrolophus pygmaeus (Rambur, 1839) (Hemiptera: Miridae), Dicyphus cerastii Wagner, 1951 (Hemiptera: Miridae) and Trichogramma achaeaeNagaraja & Nagarkatti, 1960 (Hymenoptera: Trichogrammatidae). The abundance of natural enemies were very low and, virtually, do not occur during the fall-winter seasons. We found no significant difference between the abundance of M. pygmaeus amongst tomato crops from different production mode but D. cerastii was more abundant on greenhouses of biological production mode. Parasitism rate by T. achaeae does not differ between production modes and crop seasons. Considering the major concerns of the growers by the infestation levels of their crops, together with low abundance of native natural enemies, we suggest the use of biological production mode or an inoculative or augmentative strategy to control the pest in intensive and traditional productions modes.