Endophytic fungi for biological control of whitefly and tomato leaf miner in Tanzania

Abstract

Tomato whiteflies (Bemisia tabaci) and leaf miners (Tuta absoluta) are devastating pests of tomato (Lycopersicon esculentum). Pest management using broad spectrum synthetic pesticides is discouraged due to harmful effects on human health and the environment. The objective of this study was to assess the potential of endophytic fungi as bioextracts against tomato whiteflies and leaf miners, as an alternative to synthetic insecticides in Tanzania. The study was done using morphological and molecular techniques, during January 2019 to February 2020 in Arusha region in Tanzania. Three endophyte isolates from pyrethrum (Chrysanthemum cinerariifolium) and lemon grass (Cymbopogon citratus) were identified with resemblance to members of Fusarium sp and Altenaria sp, by 90 and 82 % similarity, respectively; based on phylogenetic clustering patterns and macro- and micro-morphological characteristics. Bioextracts from endophytes of lemon grass leaves (Elg1); and pyrethrum flowers (Epf1) and leaves (Epl1), showed significant repellency properties (F0.05 (df, 15) = 27.052, P = 0.0001) on whiteflies by 54, 76 and 36%, respectively. They also caused significant lethality (F0.05 (df, 11) = 59.559, P = 0.0001) of tomato leaf miner larvae and whiteflies (F0.05 (df, 11) = 53.600, P = 0.0001). The underlying effect was attributed to possession of flavonoid and total phenolics as active ingredients in the bioextracts. This was commensurate to the levels flavonoid and total phenolic contents, which were considerably more in bioextracts of lemon grass and pyrethrum flower (F0.05 (df, 8) = 10.35, P = 0.0114) and (F0.05 (df, 8) = 40.84, P = 0.0003, respectively), than in pyrethrum leaves.