Potential alternative control for Ephestia spp. using parasitoid wasps
Different practices are already used to control lepidopteran pests in stored tobacco, mostly including chemical or physical practices, preventive or disinfesting. Biological methods, used more frequently in tobacco field sites, are not used yet in stored tobacco in Brazil. Natural enemy Habrobracon hebetor (Say, 1857) (Hymenoptera: Braconidae) is a parasitic wasp that attacks the last larvae stages of Ephestia ssp. (Lepidoptera: Pyralidae), paralysing and feeding on the larvae. The species is non-toxic, very small (1 mm), high reproductive and leaves no residue in tobacco processing. The objective of this study was to evaluate a biological sustainable method to reduce the occurrence of Ephestia spp. in farmers' and tobacco industry warehouses. Individuals of H. hebetor were bred and multiplied at Universidade de Santa Cruz do Sul (UNISC) and released in green tobacco in different Japan Tobacco International (JTI) warehouses and various tobacco farmers in different regions, with weekly monitoring of Ephestia’s population by Gachon traps. At farmers and warehouses the control of the Ephestia’s population was approximately 75 %; and at JTI warehouses the number of lepidopterans (adults and larvae) reduced significantly, replacing periodically the use of chemical disinfesting practices, reducing costs and labour. Data from 2015-2016 and 2016-2017 tobacco crops show the efficiency of this method for controlling infestations with Ephestia spp. Releasing the parasitoid wasp H. hebetor could potentially be used in different warehouses as biological control of Ephestia spp., enriching the natural population by mass-release.