Abstract During the storage period of dry tobacco and its derivatives, insect pests such as species of Ephestia Guenée (Lepidoptera: Pyralidae), popularly known as moths, cause damage to the product, being controlled mainly with physical practices and synthetic chemicals, although with limitations on their use and results. Some biological control agents, such as the parasitoid Habrobracon hebetor (Say) (Hymenoptera: Braconidae), have the potential to control these pests. This study aimed to evaluate the effect of H. hebetor release in tobacco farms and industrial warehouses, on the infestation of Ephestia spp. adults. Parasitoids were released in tobacco farmers and tobacco industry warehouses between 2016-2018, comprising two years/crop seasons. Each release consisted of 1,000 parasitoids (four times) in tobacco farmers warehouses (70 m2) and 30,000 (five times) in tobacco industry warehouses (8,000 m2). Pheromone-baited sticky traps were used to weekly monitor the average number of adults of Ephestia spp. in warehouses with (WP) and without parasitoid release (NP). The average number of adults of Ephestia spp. captured in the traps in WP environments at farmers and industry level was significantly lower than the average captured in NP from the third and fifth weeks. In the following weeks, the averages of Ephestia spp. were always significantly lower in the WP environments until the end of monitoring. Therefore, the use of H. hebetor for moth control should be considered as part of a biological control program in stored tobacco environments.

RESUMEN El pulgón Myzus persicae (Sulzer) (Hemiptera: Aphididae) es considerado una de las principales plagas en cultivos de tabaco. Conocer sus enemigos naturales, como las avispas parasitoides, es el primer paso para desarrollar estrategias de manejo para el control biológico de los pulgones utilizando agentes locales. Para el éxito en la utilización de esta herramienta, se debe tener en cuenta algunos factores ambientales como la tolerancia térmica. En ese sentido, este trabajo tuvo como objetivo realizar una evaluación de la ocurrencia de los parasitoides de M. persicae asociados al cultivo del tabaco en el estado de Rio Grande do Sul, Brasil, así como, evaluar la influencia de la temperatura en la ocurrencia de estas especies parasitoides. Durante cuatro temporadas de cultivo, se realizaron colectas de hojas de tabaco infestadas con pulgones en 42 ciudades de Rio Grande do Sul. Las hojas con pulgones fueron acondicionadas en recipientes plásticos por diez días, para posterior identificación y verificación de la emergencia de los parasitoides. Se muestrearon un total de 2963 individuos emergidos, de dos especies: 78% a Aphidius colemani Viereck (Hymenoptera: Braconidae) y 22% a Praon volucre (Holiday) (Hymenoptera: Braconidae). De las 42 ciudades muestreadas, se detectó la presencia de parasitoides en 25 de ellas. En las condiciones en que se realizó el estudio, se constató que la temperatura ejerció influencia directa sobre las poblaciones de parasitoides de M. persicae. Los individuos de P. volucre ocurrieron preferentemente en temperaturas inferiores a los 22 °C, a diferencia de A. colemani, que presentaron preferencia por temperaturas mayores a los 22 °C, observándose una tolerancia térmica diferente entre las dos especies.

ABSTRACT The aphid Myzus persicae (Sulzer) (Hemiptera: Aphididae) is considered one of the main pests in tobacco crops. By knowing their natural enemies, such as parasitoid wasp, is the first step to develop management strategies for the biological control of the aphids using local agents. For the success of using this tool, it must be considered some environmental factors like thermal tolerance. Therefore, the objective of this work was to survey the occurrence of the parasitoids of M. persicae associated with tobacco crops in the state of Rio Grande do Sul, Brazil, as well as to evaluate the influence of temperature on the occurrence of these parasitoid species. During four crop seasons, tobacco leaves infested with aphids were collected in 42 cities of Rio Grande do Sul. The leaves with aphids were conditioned in plastic containers for ten days for later screening and verification of parasitoids' emergence. In total, 2963 individuals of two emerging species were sampled: 78% were Aphidius colemani Viereck (Hymenoptera: Braconidae), and 22% were Praon volucre (Haliday) (Hymenoptera: Braconidae). Among the 42 cities sampled, the occurrence of parasitoids was detected in 25 of them. Under the conditions of this study, it was confirmed the influence of the temperature on the populations of the parasitoids of M. persicae. Individuals of P. volucre occurred preferably in temperatures below 22 °C, unlike to A. colemani, which preferred higher temperatures, above 22 °C, showing a different thermal tolerance between both species.