No abstract

One of the main obstacles to feeding the world is the fungal leaf spot disease, which has a negative impact on plants' photosynthetic areas and significantly lowers crop quality and output. To manage fungi that pose a serious hazard to both humans and the environment, various chemical fungicides are utilized. The goal of the current study was to determine whether local isolates of three Trichoderma spp. (Trichoderma viride, Trichoderma harzianum, and Trichoderma asperellum) had any antagonistic effects in vitro against the pathogenic fungi Alternaria alternata, Fusarium solani, Fusarium oxysporum, Aspergillus flavus, Aspergillus sydowii, and Alternaria sp. Trichoderma viride showed the greatest growth inhibition against all of the tested pathogenic fungi, followed by Trichoderma harzianum and Trichoderma asperellum. It was shown that all three Trichoderma species strongly inhibited the mycelial growth of fungal pathogens. Compared to other isolated fungi, Trichoderma species inhibited Alternaria alternata mycelial growth more, whereas in Fusarium oxysporum least amount of mycelial growth inhibition was observed. These findings imply that Trichoderma species can function as an effective biocontrol agent against the fungi responsible for tomato leaf spot disease.

Common beans collected from different sites of Kashmir valley were found infected with Alternaria alstroemeriae causing pod rot. The diseased pods appeared dark brown to black. The decayed tissues became soft and watery. The causal pathogen was isolated and cultured on PDA medium for cultural and microscopic examination. Its pathogenicity was confirmed following Koch's postulates. Results revealed that the pods were infected with Alternaria alstroemeriae resulting in rot of beans. Efficacy of ethanolic, methanolic and aqueous extracts of different plants against the isolated pathogen was evaluated. Amongst the different phytoextracts, ethanolic extract of Salvia moorcroftiana proved most effective in inhibiting the mycelial growth of the pathogen (showing mycelial growth inhibition of 86.66%) whereas the aqueous extract of Inula racemosa proved least effective (showing mycelial growth inhibition of 9.23%) at the standard concentration Ethanolic extracts of S.moorcroftiana proved more effective than methanolic and aqueous phytoextracts. Higher concentrations showed more efficacy than lower concentrations.

A study was done to investigate the antagonistic effects of three Trichoderma viride isolates (TV1, TV2 and TV3) on Sclerotinia sclerotiorum. The results revealed that the isolate TV1 proved to be the best in suppressing the mycelial growth by 77% after 7 days of incubation. However 74.91% and 50% inhibition were recorded on 5th and 3rd days of incubation, respectively. The isolate TV2 caused inhibition of 74.77% on 7th day, and 72.66% and 48.33% after 5th and 3rd days of incubation, respectively. 72.54%, 70.41%, and 51.66% inhibition in mycelial growth of the pathogenic fungus was caused by TV3 isolate after 7th, 5th, and 3rd days of incubation respectively. All the test isolates of T. viride showed a significant effect on the vigour index of common bean. The maximum germination percentage was observed on treatment with TV1 isolate (85%) followed by TV2 (83%) and TV3 (81%) respectively, in comparison to untreated seeds which showed a germination percentage of 73%. Maximum vigour index was shown by those plants whose seeds were treated with TV1 (11560), followed by those treated with isolate TV2 (10707) and TV3 (9234), whereas the control plants showed significantly lower vigour index of 7446 in comparison to treated plants.