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.

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The study was conducted during 2018−19 and 2019−20 to evaluate effectiveness of the Trichoderma asperellum liquid formulation for the management of tomato damping-off in the nursery. The experiment was conducted for two consecutive seasons in a randomized block design with seven treatments and three replications. T. asperellum formulation improved seed germination and controlled the damping-off diseases in tomatoes when compared with control. All the treatments performed better over control, in the first season, the antagonist’s application showed 75.75% seed germination; however, it was 60.13% in control. There was 10.93 to 20.38% seedling mortality due to disease which was comparatively lower than the control (26.98%). A similar trend of seed germination and disease incidence was observed in the second season. In addition to managing the disease, the antagonist certainly promoted vegetative growth which was reflected as increased shoot and root length in comparison to control during both seasons. During the first season, shoot length ranged 10.90–12.85 cm as compared to the control (8.72 cm) and root length ranged from 3.21–3.65 cm which was greater than the control. Almost a similar trend in the vegetative growth parameters of seedlings was observed during the second season. The present investigation showed that the tested antagonist’s formulation could efficiently manage the tomato damping-off as well as encouraged the vegetative growth of seedlings which ultimately ensured better and healthy seedling. This formulation can successfully be used through different methods to take care of tomato damping off.

Background In recent years, Microtermes obesi (Holmgren) (Blattodea: Termitidae) has been recorded as a major pest of tea crop, causes significant losses in production. Managing termite pests in tea crops through an integrated approach has been suggested, and the use of microbial biocontrol agent is one of the economical methods. The present study evaluated the pathogenic efficacy of an entomopathogenic fungus Metarhizium anisopliae s.l. (= M. anisopliae) against M. obesi damaging tea plants under field conditions. Results Metarhizium anisopliae s.l. was formulated as 5% aqueous suspension (AS). Large-scale field trials with formulated entomopathogen revealed that 1000 and 1200 ml concentrations of M. anisopliae s.l. 5%AS (each concentration containing 2 × 107 conidia/ml) each in 400 l of water/ha significantly (P < 0.05) reduced the population of M. obesi in tea gardens at Dooars and Darjeeling regions, India. In the field study, M. anisopliae s.l. was more effective than the standard insecticide and was non-pathogenic on the beneficial insects present in the tea gardens. In addition, M. anisopliae s.l. 5%AS had no phytotoxic effect on the tea leaves, with acceptable organoleptic attributes. Conclusion Metarhizium anisopliae s.l. isolate can be commercialized as an alternative natural termiticide to reduce the load of synthetic insecticides in the tea crop.