Trichoderma is the most commonly used fungal biocontrol agent throughout the world. In the present study, various Trichoderma isolates were isolated from different vegetable fields. In the isolated microflora, the colony edges varied from wavy to smooth. The mycelial forms were predominantly floccose with hyaline color and conidiophores among all the strains were highly branched. Based on morphological attributes, all the isolates were identified as Trichoderma harzianum. The molecular identification using multilocus sequencing ITS, rpb2 and tef1α, genes further confirmed the morphological identification. The average chitinase activity varied from 1.13 units/mL to 3.38 units/mL among the various isolates, which increased linearly with temperature from 15 to 30 °C. There was an amplified production in the chitinase production in the presence of Mg⁺ and Ca²⁺ and Na⁺ metal ions, but the presence of certain ions was found to cause the down-regulated chitinase activity, i.e., Zn²⁺, Hg²⁺, Fe²⁺, Ag⁺ and K⁺. All the chitinase producing Trichoderma isolates inhibited the growth of tested pathogens viz., Dematophora necatrix, Fusarium solani, Fusarium oxysporum and Pythium aphanidermatum at 25% culture-free filtrate concentration under in vitro conditions. Also, under in vivo conditions, the lowest wilt incidence and highest disease control on Fusarium oxysporum was observed in isolate BT4 with mean wilt incidence and disease control of 21% and 48%, respectively. The Trichoderma harzianum identified in this study will be further used in formulation development for the management of diseases under field conditions.

Rice blast is considered one of the most important fungal diseases of rice. Although diseases can be managed by using resistant cultivars, the blast pathogen has successfully overcome the single gene resistance in a short period and rendered several varieties susceptible to blast which were otherwise intended to be resistant. As such, chemical control is still the most efficient method of disease control for reducing the losses caused due to diseases. Field experiments were conducted over two successive years, 2018 and 2019, in temperate rice growing areas in northern India. All the fungicides effectively reduced leaf blast incidence and intensity, and neck blast incidence under field conditions. Tricyclazole proved most effective against rice blast and recorded a leaf blast incidence of only 8.41%. Among the combinations of fungicides, azoxystrobin + difenoconazole and azoxystrobin + tebuconazole were highly effective, recording a leaf blast incidence of 9.19 and 10.40%, respectively. The chemical combination mancozeb + carbendazim proved less effective in controlling the blast and it recorded a disease incidence of 27.61%. A similar trend was followed in neck blast incidence with tricyclazole, azoxystrobin + difenoconazole, and azoxystrobin + tebuconazole showing the highest levels of blast reductions. It is evident from the current study that the tested fungicide combinations can be used as alternatives to tricyclazole which is facing the challenges of fungicide resistance development and other environmental concerns and has been banned from use in India and other countries. The manuscript may provide a guideline of fungicide application to farmers cultivating susceptible varieties of rice.

Apple cankers are extremely destructive diseases threatening the global apple industry through direct and indirect losses. The population structure of the pathogens is of paramount significance for the development of efficient management strategies. Therefore, phenotypic, pathogenic, and genetic diversity of Diplodia seriata causing black rot canker of apple was investigated in this study. All the isolates were included for investigating the in vitro mycelial growth, conidial dimensions, and pathogenic variability on two-year-old potted apple seedlings. The ISSR approach was used to investigate the molecular diversity of D. seriata. Mycelial growth rates were found to vary significantly amongst the isolates; however, there were no major variations seen between the different geographical groupings of isolates. Pathogenicity tests revealed variations in the size of cankers among the isolates indicating the presence of virulence variability. The isolates were segregated into three virulence groups based on canker length. The Bayesian analyses of ISSR data divided the isolates into two genetic clusters. The genetic clustering of the isolates revealed no relationship with geographical origin of the isolates. Furthermore, no direct relationship of genetic clustering was observed with morphological or pathogenic variability. The ISSR primers revealed very high level of variability in D. seriata; however, no distinct populations of the pathogen existed which is an indication of high level of gene flow between the diverse geographical populations. According to our knowledge, this is the first thorough investigation on the diversity of D. seriata associated with apple black rot canker in India.

Apple is considered as an important fruit crop in temperate regions of the world including India. It is one of the major fruit crops, with a considerable area under cultivation throughout the world and a large associated population. Despite this, the productivity of this important fruit is not up to the expected standard. To gain a practical understanding of the low productivity of apple fruit and its probable causes, a study was undertaken to analyze productivity differentials and their determinants to enable sustainable cultivation. A multistage sampling procedure was adopted to select districts, horticultural zones, and villages, and data were collected from randomly selected apple growers (300). The collected data were empirically analyzed with simple descriptive statistics, logistic regression, polynomial plots, and inferential statistics such as t-tests. The results indicated that apple yields followed a sigmoidal pattern, with the average yield per hectare for the current season as 9.43 t/ha, which depends on experience, education, annual income, and the adoption rate of apple growers. This yield average was significantly lower than the yield of the previous season at a probability level of 1%. To determine the root cause of low productivity, different constraints were studied, creating yield disparities in different quarters; hence, their percentage and value contributions (socioeconomic 11.1%, credit 4.2%, pests and diseases 0.05%, technology 0.9%, extension 2.0%, and market 3.5%) were also established in the study. The study will be of great interest to the relevant authorities in the study area, and the areas globally having similar congenial agro-climatic conditions, who are seeking to address the issues raised in this study through sustainable policy decisions. The different constraints that were the fundamental reasons for low productivity and that prevented the apple growers from adopting innovative techniques/improved practices to increase their yields need to be addressed as a matter of urgency.

Grape an important fruit crop, has been found to face a serious threat due to anthracnose disease. The disease on leaves appeared as small irregular dark brown lesions, which later developed greyish centre with dark brown margins that eventually dried and dropped resulting in peculiar shot hole appearance. On twigs (vines) the disease initially appeared as light brown circular lesion which on elongation became elliptical and developed sunken ashy grey centre. Coalescing of numerous such lesions culminated in canker formation. Berry symptoms were initiated as circular reddish brown lesions, which later coalesced, resulting in shrivelling and mummification of berries. The pathogen was isolated on potato dextrose agar medium and its pathogenicity was proved. The fungus produced circular, cottony colony with light green centre and creamish margins which later turned olive green with radial furrows. Acervuli and conidia were formed 10 days after incubation at 25±2 oC. Conidia (6.21 × 3.87μm) were oblong and hyaline to brownish in colour. Based on its colony characters, morphological characters and by comparing with authentic descriptions as well as through pathogenicity the pathogen causing anthracnose disease of grapes was identified as Gloeosporium ampelophagum (Pass.)Sacc. The fungus showed highest mycelial sporulation of 0.81×106/ml on oat meal agar with a pH 6.5 at 25-30 oC. Among the bio-agents screened, Trichoderma harzianum exhibited maximum inhibition in mycelial growth of 62.53 per cent that can be effectively used for the management of the disease.