Role of beneficial fungi in managing diseases and insect pests of tea plantation

Abstract

The effectiveness of Trichoderma atroviride, T. asperellum, T. harzianum, against targeted tea disease causing pathogen, Fusarium solani (dieback), Beauveria bassiana against tea mosquito (Helopeltis theivora), and Metarhizium anisopliae against the red spider mite, Oligonychus coffeae Nietner, and the live wood eating termite (Microcerotermes beesoni Snyder), respectively were evaluated under laboratory and field conditions. The Trichoderma isolates showed effective control of F. solani (64.6 to 71.7%) under laboratory conditions, while the wettable powder (WP) formulation could reduce dieback disease incidence (57.1 to 77.7%) over control, under field conditions. The post prune application of Trichoderma asperellum on light pruned (LP) and application of T. asperellum as well as T. harzianum on deep skiffed (DS) tea fields showed a significant growth promotional response. The treated bushes could produce an average number of 421.2 and 398.4 shoots when it was applied 7.5 and 5.0% (w/v), respectively, which was higher than the number of shoots recorded in the control plots (259.4). The antagonist also induced comparatively higher shoot length (6.85-7.99 cm) than the untreated control plots (5.13-6.38 cm). The B. bassiana isolates (2 × 10 9 conidia/ml) exhibited 71.5 to 93.0% control of 2nd instar nymphs of H. theivora under in vitro conditions. However, addition of different adjuvants resulted in enhanced mortality. Under field conditions, the highest reduction of tea mosquito population of 52.3% was noted when B. bassiana (1 × 10 9 cfu/ml) was sprayed along with Tween 20 plus and crude sugar. However, the wettable powder formulation of this EPF along with jaggery reduced the insect incidence. The M. anisopliae effectively controlled the red spider mite to the tune of 46.3 to 63.8% under laboratory conditions, while the wettable powder formulation of this isolate was more effective against the termite, resulting in the reduction of infestation to the tune of 84.2% under field conditions.

Pathogenic potential of Metarhizium anisopliae and Lecanicillium longisporum on tea mosquito bug, Helopeltis theivora Waterhouse (Hemiptera: Miridae)

“…This indicates that the adhesion of EPF spores over TMB is very high in the dipping process and adhesion spores will germinate, penetrate to the haemocoel then rapidly cause insect mortality (Ghaffari et al, 2017;Aw & Hue , 2017). Kumhar et al (2020) reported that the mortality was significantly dependent on spore concentration. A similar observation was made in the present study too.…”

Niche differentiation of microbes and their functional signatures in Assam type tea (Camellia sinensis var. assamica)

“…Members of the genus Beauveria (especially, Beauveria bassiana) have the ability to colonize multiple plant hosts without causing any apparent disease or showing secondary symptoms, yet retaining the capacity to infect insects and invoke induced systemic resistance (Wei et al 2020). A eld trial in Northeast India has reported Beauveria bassiana to be effective against Helopeltis theivora (a sucking pest of tea-leaves) and other tea pests (Borkakati and Saikia 2019; Kumhar et al 2020). Another entomopathogenic fungus Metarhizium (especially, M. anisopliae) is also regularly used as a broad spectrum insect biopesticide (Singha et al 2011).…”

Trichoderma asperellum as a promising mycofungicide for managing the dieback disease of tea Camellia sinensis (L.) Kuntze

“…It was found that Trichoderma WP formulation controlled the dieback disease of tea to a great extent when sprayed at 2.5 and 5.0 g/liter concentration and performed better than the commercial formulation of the antagonist. Light pruned (LP) and deep skipped (DS) tea bushes showed enhanced vegetative growth as compared to control [16]. Foliar spray of T. harzianum and T. viride on wheat crop managed head blight disease caused by Fusarium graminearum under greenhouse conditions better than control [17].…”