The Journal of Plant Disease Sciences is the official publication of the Association of Plant Pathologists, housed within the Department of Plant Pathology, Dr. Panjabrao Deshmukh Krishi Vidyapeeth, Akola (M.S.). The journal serves as a dedicated platform for publishing research in Mycology and Plant Pathology, adhering to the constitution and bylaws of the society. It features peer-reviewed research articles, reviews, and short communications covering various aspects of plant disease management, host-pathogen interactions, epidemiology, disease diagnostics, and sustainable agricultural practices. The journal primarily publishes work by association members but is open to contributions from the broader scientific community. Committed to maintaining high academic and ethical standards, the Journal of Plant Disease Sciences aims to advance scientific knowledge in plant pathology while supporting agricultural sustainability and crop protection. Indexing details: NAAS Score - 4.20, World Cat, WorldCat Discovery, Publons, Scilit, Google Scholar, Base Indexing, Ebsco, Wos-Applied, Cross ref, ICI, ASI
ISOLATION, IDENTIFICATION, AND PATHOGENICITY OF SP. CAUSING STEM ROT IN DRAGON FRUIT
Dragon fruit is an emerging high-value crop in tropical and subtropical regions, affected by stem rot disease, posing a significant threat to its commercial cultivation. The present study was undertaken during 2023–2024 at ICAR–National Institute of Abiotic Stress Management (NIASM), Baramati, to isolate, identify, and assess the pathogenicity of Fusarium spp. associated with stem rot in dragon fruit. Disease samples exhibiting typical necrotic lesions were collected from ICAR-NIASM orchards and nearby farmer fields. Pathogen isolation was performed on potato dextrose agar (PDA), resulting in pure cultures from 20 out of 25 samples. Eight distinct isolates were characterized based on cultural and morphological features, including colony pigmentation, hyphal structures, and conidial measurements. Macroconidia were typically 3–5 septate, slender, and foot-shaped at the basal cell, while microconidia were oval to spindle-shaped and 0–2 septate; chlamydospores were observed in select isolates. Pathogenicity was confirmed via a detached cladode assay under controlled laboratory conditions using a standardized spore suspension (1×10⁶ spores/mL). Inoculated cladodes developed characteristic stem rot symptoms, and the pathogen was successfully re-isolated, fulfilling Koch's postulates. The findings confirm Fusarium oxysporum and F. solani as key causal agents of stem rot in dragon fruit. This study provides foundational data for targeted disease management strategies and contributes to sustainable dragon fruit production in India.
SCREENING OF CUCUMBER CULTIVARS TO DOWNY MILDEW CAUSED BY IN NATURAL FIELD CONDITIONS
Downy mildew, caused by Pseudoperonospora cubensis, is a major limiting factor in cucumber production, especially during the Kharif season under humid conditions. The present study was carried out to assess the field resistance of twelve cucumber cultivars against downy mildew during the Kharif 2023 season. Observations were made on the time of first disease appearance and percent disease index (PDI) at different crop stages. The disease first appeared between 34 to 47 days after sowing (DAS), with Lalit-22 showing the earliest and Pant Khira-1 the latest onset. At 40 DAS, nine cultivars showed no symptoms, while Lalit-22, Honey, and Netra-007 showed early infections with PDIs of 15.66%, 12.06%, and 14.33%, respectively. By 70 DAS, disease severity had progressed in all cultivars, with final PDI values ranging from 23.85% to 71.66%. Based on disease response, Ankur-07 and Gujarati Nirmala-2 were rated as moderately resistant, whereas Lalit-22, Honey, and Netra-007 were found susceptible. The remaining cultivars were moderately susceptible. The findings underscore the importance of delayed disease onset and reduced final severity as indicators of resistance. Cultivars Ankur-07 and Gujarati Nirmala-2 may be valuable genetic resources for breeding programs aimed at improving downy mildew resistance in cucumber.
DETECTION OF SEED BORNE MYCOFLORA OF SOYBEAN
Soybean is one of the most valuable legume crops globally and an excellent source of vegetable oil. However, its productivity is significantly affected by seed-borne pathogens that contribute to yield reduction. In the present study, seed samples of five soybean cultivars—JS-335, MAUS-162, AMS-1001, AMS-MB-5-18, and MAUS-71—were collected and evaluated for seed-borne mycoflora using the standard blotter paper method, standard agar plate method, and rolled paper towel method as per ISTA guidelines. A total of nine seed-borne fungi, including both saprophytic and parasitic species, were identified: Alternaria alternata, Rhizoctonia bataticola, Curvularia lunata, Fusarium solani, Cladosporium cladosporioides, Drechslera rostrata, Aspergillus niger, Aspergillus flavus, and Rhizopus stolonifer. Among the detection methods, the standard blotter method recorded the highest frequency of fungal occurrence, with Fusarium solani being the most dominant (25.25%), followed by A. flavus (16.75%), A. niger (13.27%), D. rostrata (4.90%), and others in decreasing order. R. bataticola was predominantly detected using the agar plate method, showing 18.35% frequency. These findings emphasize the importance of seed health testing and fungal detection methods for effective disease management in soybean cultivation.
IN VITRO ALTERNARIA ALTERNATA EVALUATION OF BOTANICALS AGAINST INDUCING LEAF BLIGHT IN GROUNDNUT
Groundnut is a vital legume crop cultivated worldwide for its high oil and protein content, playing a significant role in food security and agro-industrial development, especially in India. However, its production is adversely affected by foliar diseases, particularly leaf blight caused by Alternaria alternata, which can lead to yield losses of up to 20%. This study aimed to evaluate the in vitro antifungal efficacy of seven botanicals — Allium sativum, Azadirachta indica, Zingiber officinale, Allium cepa, Curcuma longa, Datura stramonium, and Ocimum sanctum — against A. alternata using the poisoned food technique on potato dextrose agar (PDA). Aqueous extracts of the botanicals were tested at 15% and 20% concentrations. Results revealed significant suppression of mycelial growth by all botanicals compared to the control, with enhanced efficacy at the higher concentration. Zingiber officinale exhibited the strongest antifungal activity at both concentrations, achieving 92.21% inhibition at 20%, followed by Ocimum sanctum and Azadirachta indica. The study underscores the potential of plant-based extracts, particularly ginger, tulsi, and neem, as eco-friendly alternatives to chemical fungicides in managing leaf blight in groundnut. These findings contribute to sustainable disease management strategies aligned with environmental and food safety concerns.
HARNESSING DEFENCE INDUCERS FOR THE MANAGEMENT OF POWDERY MILDEW IN LINSEED
Linseed suffers significant grain yield losses due to various abiotic and biotic stress factors, with powdery mildew caused by Oidium lini (Skoric) being one of the most critical biotic threats. This disease reduces photosynthetic efficiency and grain yield, manifesting in symptoms such as drooping and yellowing of leaves, reduced capsule number, and smaller seed size. To address this, a study was conducted from 2019–2020 to 2021–2022 to evaluate the effectiveness of defence inducers and a fungicide in managing powdery mildew.The treatments included salicylic acid (50 and 100 ppm), monopotassium phosphate (1%), sodium propionate (1%), and hexaconazole (0.1%). Among these, seed treatment followed by foliar application of salicylic acid at 50 ppm at 30 and 45 days after sowing (DAS) showed the highest disease reduction (34.99%), maximum seed yield (1219 kg/ha), and the highest incremental cost-benefit ratio (ICBR) of 1:6.71.These findings underscore the potential of systemic acquired resistance (SAR) and induced systemic resistance (ISR)-based inducers as eco-friendly alternatives to conventional fungicides in the sustainable management of powdery mildew in linseed.
INFLUENCE OF WEATHER ON THE PROGRESS OF CORYNESPORA LEAF SPOT IN COTTON
Corynespora leaf spot in three BG II cotton hybrids: Aadhya, Akira, and US 7067. Disease severity was recorded weekly from the first appearance of symptoms through to the boll bursting and picking stage, using a 0 to 4 scale on twenty randomly tagged plants per plot.Concurrently, daily weather data—including maximum and minimum temperatures, morning and evening relative humidity, rainfall, number of rainy days, sunshine hours, wind speed, and evaporation—were recorded from the meteorological observatory. Correlation and multiple regression analyses were performed between percent disease index (PDI) and weather parameters using MS Excel.Results revealed that morning relative humidity and sunshine hours showed a significant positive correlation with PDI. In contrast, maximum and minimum temperatures, number of rainy days, and wind speed had significant negative correlations. Multiple regression analysis identified minimum temperature, evening relative humidity (RH II), and rainfall as common factors that significantly influenced the disease progress across all three cotton hybrids.
STRATEGIES FOR MANAGING INDUCED LEAF AND FLOWER BLIGHT DISEASE IN MARIGOLD
Marigold (Tagetes spp.) is a widely cultivated commercial flower crop in India. In the South Gujarat region, significant damage to marigold crops has been observed due to the foliar pathogen Alternaria tenuissima, which causes leaf spot and flower blight. This study, conducted over a three-year period, aimed to evaluate the efficacy of different fungicidal treatments for managing this disease.Results showed that three foliar sprays of either hexaconazole 4% + zineb 68% WP (0.072%, i.e., 1g/lit), mancozeb 75WP (0.225%, i.e., 3g/lit), or tebuconazole 50% + trifloxystrobin 25% WG (0.03%, i.e., 0.4g/lit) were effective in controlling leaf and flower blight. Sprays were applied at the onset of disease, followed by two subsequent sprays at 15-day intervals.Among the treatments, hexaconazole 4 + zineb 68 WP showed the highest Incremental Cost-Benefit Ratio (ICBR) of 1:4.73, followed by mancozeb 75WP (ICBR 1:4.32) and tebuconazole 50 + trifloxystrobin 25WG (ICBR 1:3.87). In addition to effective disease control, these treatments also enhanced flower yield and were found to be non-phytotoxic to the plants and flowers.
SCREENING OF LINSEED ( L.) GERMPLASM UNDER EPIPHYTOTIC CONDITIONS AGAINST POWDERY MILDEW AND WILT DISEASES
A set of 122 linseed germplasm accessions was evaluated for their resistance to powdery mildew and wilt diseases under epiphytotic conditions at the AICRP Linseed experimental block, College of Agriculture, Nagpur, during the cropping season of 2023–24. The objective of the study was to identify resistant sources for use in linseed breeding programs targeting disease resistance.Out of the 122 germplasm entries, nine accessions (23045, 24032, 24035, 24043, 24049, 24050, 24051, 25024, and 27025) exhibited a highly resistant response to powdery mildew. Furthermore, all entries were also tested under wilt sick plot conditions to evaluate their response to wilt disease. Among these, one entry (27042) showed a highly resistant reaction to wilt, while 12 entries (23054, 24031, 24036, 24041, 24042, 25021, 25023, 27021, 27025, 27030, 27033, and 27034) were categorized as resistant.The remaining accessions were classified as moderately susceptible, susceptible, or highly susceptible to one or both diseases.
ISOLATION AND IDENTIFICATION OF PLANT GROWTH PROMOTING RHIZOBACTERIA ISOLATES IN THE MARATHWADA REGION OF MAHARASHTRA
Chickpea is one of the most important pulse crops, contributing a lion’s share to the world’s gram production. Fusarium wilt is a serious soil-borne disease that affects chickpea productivity. Biological control using native Plant Growth Promoting Rhizobacteria (PGPR) isolated from rhizosphere soils offers a sustainable and eco-friendly solution for managing this disease. These PGPR also enhance plant growth by increasing nutrient uptake, siderophore production, and the synthesis and release of growth-promoting hormones.The present study was conducted to isolate and identify potential native PGPR species from the Marathwada region of Maharashtra for the dual purpose of managing Fusarium wilt and promoting chickpea growth. A total of 19 rhizosphere soil samples were collected from healthy chickpea fields across three agro-climatic zones of the region.Among the isolates, species coded as CPP produced medium-sized, white, convex, smooth, regular colonies with yellowish-green pigmentation, gram-negative reaction, rod-shaped cells, and negative sporulation. In contrast, species coded as CSN, CSB, and CSO formed small-sized, white, convex, smooth colonies with irregular to regular margins, light green pigmentation, gram-negative reaction, rod-shaped cells, and negative sporulation.
CHEMICAL SYNTHESIS OF COPPER NANOPARTICLE AND ITS EFFICACY AGAINST IN-VITRO PHYTOPHTHORA NICOTIANAE
Various Phytophthora species have long been associated with different citrus diseases, including gummosis, root rot, fruit brown rot, and citrus decline worldwide, including in India. Among these, Phytophthora parasitica has gained considerable attention due to its significant role in causing citrus gummosis, a major factor contributing to yield losses. Studies have shown that P. parasitica can lead to approximately 10–30% yield reduction due to gummosis. Considering this impact, the present study aims to synthesize copper nanoparticles (CuNPs) and evaluate their antifungal efficacy against P. parasitica. Due to their large specific surface area and low cost, copper nanoparticles have garnered substantial interest. In this study, CuNPs were successfully synthesized using a novel, simple method based on the chemical reduction of aqueous copper salt at low temperatures (80 °C), with ascorbic acid acting as a reducing agent. The maximum absorbance at 340 nm in the UV-Vis spectroscopic analysis confirmed the presence of CuNPs in the reaction mixture. Efficacy experiments revealed that CuNPs at 50 ppm and 100 ppm concentrations significantly inhibited the mycelial growth of P. parasitica by 59.25% and 100%, respectively. Overall, the present study highlights the potential of synthesized CuNPs as a nano-fungicide at low concentrations, offering an eco-friendly alternative to synthetic fungicides and helping to reduce harmful environmental impacts.
EFFICACY OF FUNGICIDE MOLECULES AND BIOAGENTS AGAINST CHARCOAL ROT OF SOYBEAN
Soybean is one of the most economically important legumes worldwide. However, diseases serve as significant biotic constraints in soybean production. Among them, charcoal rot caused by Macrophomina phaseolina is a major disease responsible for substantial yield losses. In the present investigation, five fungicides and three bio-agents were evaluated for their efficacy against M. phaseolina. In in vitro conditions, Carboxin 37.5% + Thiram 37.5% DS and Carbendazim 12% + Mancozeb 63% WP exhibited 100% inhibition of the mycelial growth of the pathogen. Among the bio-agents tested, Trichoderma viride showed the highest mycelial growth inhibition (58.33%), followed by Pseudomonas fluorescens (38.88%). Under greenhouse conditions, Carboxin 37.5% + Thiram 37.5% DS and Carbendazim 12% + Mancozeb 63% WP were found to be the most effective, achieving 77.78% disease control of charcoal rot. This was followed by Thiophanate methyl 45% + Pyraclostrobin 5% FS (55.56%), Trichoderma viride (33.33%), and Pseudomonas fluorescens (22.22%).
LEAF ANATOMICAL DIFFERENCES IN RESISTANT AND SUSCEPTIBLE MAIZE GENOTYPES AGAINST LEAF BLIGHT DISEASE
Turcicum leaf blight (TLB) disease is the major limiting factor of maize production. It reduces the yield of maize crop considerably all over the world. Turcicum leaf blight of maize is incited by fungus . The present study involved screening of eighty nine maize genotypes for resistance against TLB disease under artificially epiphytotic conditions during , 2024. Among the eighty nine maize genotypes forty six genotypes were found resistant and thirty nine were found moderately resistant, where as two genotyes each were moderately susceptible and two were susceptible to Turcicum leaf blight disease. On comparison, within resistant, moderately resistant, moderately susceptible and susceptible genotypes made, it was evident that stomatal frequency was significantly higher on both surface of susceptible and moderately susceptible genotypes compared to resistant and moderately resistant genotypes however, trichomes frequency significantly higher on resistant genotypes.
DYNAMICS OF LEAF BLIGHT DISEASE CAUSED BY ALTERNARIA ALTERNATA IN GERBERA UNDER PROTECTED CULTIVATION
Gerbera is an important flower crop cultivated globally under a wide range of climatic conditions. However, disease occurrence remains a major constraint in protected cultivation, primarily due to the warm and humid environment. Among the various diseases reported in gerbera, leaf blight and powdery mildew are the most devastating. During the present investigation under protected conditions, leaf blight caused by Alternaria alternata was identified as a major recurring disease. Weather conditions during the 29th to 35th standard weeks (July and August) were found to play a significant role in the rapid progression of the disease. This period can therefore be considered as the critical window for leaf blight development in gerbera. The correlation matrix revealed a highly significant and positive relationship between leaf blight severity and relative humidity during the study, highlighting the influence of environmental factors on disease incidence under protected cultivation.
STUDIES ON VIABILITY OF BACTERIAL BIOAGENTS FORMULATION IN VACUUM PACKING COMPARED TO CONVENTIONAL PACKING
The shelf life and viability of bacterial bioagents like Pseudomonas and Bacillus species are significantly influenced by factors such as formulation, moisture content, and resilience to adverse climatic conditions. Numerous commercial formulations of Pseudomonas and Bacillus species are widely available and commonly used for the management of soil-borne plant diseases. Understanding the optimal storage conditions is essential for maintaining a high number of viable propagules over time. This study found that vacuum packing did not provide any significant advantages over conventional packaging methods. Moreover, storing the bioagents in a refrigerator at 4 °C proved to be more effective than other storage conditions such as room temperature (27 ± 2 °C), incubator (24 ± 2 °C), and deep freezer (-20 °C).
INVESTIGATION ON WHEAT GERMPLASM’S REACTION TO BROWN RUST INDUCED BY ERIKS PUCCINIA TRITICINA
Wheat is the main cereal crop cultivated by Indian farmers after rice. Many fungal diseases are reported in wheat but brown rust is the most important air borne foliar disease which cause severe losses in wheat production and grain quality worldwide. There are many principles of disease management, among them resistance source is an eco-friendly and effective measure. In this study three hundred wheat genotypes were tested in the field under artificially inoculated condition to calculate their disease reaction, average coefficient of infection and area under disease progress curve. From them thirty two genotypes were showed immune response, twenty four genotypes were found resistance against brown rust pathogen with AUDPC value between 0 to 10. Eighty genotypes showed moderately resistance response with AUDPC value 10 to 100 and seventy seven were observed moderately susceptible reaction with AUDPC 100 to 500. Remaining 87 genotypes recorded to have susceptible reaction withAUDPC value more than 500.
Deciphering the Promising Varieties of Pigeon Pea for Wilt Resistance and Yield Potential in the Northern Dry Zone of Karnataka
Pigeon pea (Cajanus cajan (L.) Millsp.) is a major legume crop cultivated extensively in rainfed semi-arid regions and plays a vital role in India's pulse production. However, Fusarium wilt (Fusarium udum) is a major constraint, causing significant yield losses.This study aimed to assess the performance of different pigeon pea varieties for wilt resistance and yield potential through on-farm demonstrations in Vijayapur district, Karnataka, over two cropping seasons (2019–20 and 2020–21).
Epidemiological Studies on Alternaria tenuissima Causing Leaf Spot and Flower Blight of Marigold
Marigold (Tagetes spp.) is a widely cultivated commercial flower crop in South Gujarat. However, its yield is significantly impacted by leaf spot and flower blight, primarily caused by Alternaria tenuissima.This study aimed to examine the epidemiological factors influencing disease incidence under natural field conditions at the Floriculture Research Farm, NAU, Navsari, during Kharif seasons of 2020 and 2021. The experiments were conducted on the Punjab Gainda-1 variety.
BIOCHEMICAL STUDIES ON LEAF SPOT AND FLOWER BLIGHT CAUSED BY ALTERNARIA TENUISSIMA IN MARIGOLD
Marigold (Tagetes spp.) is an important traditional flower crop widely cultivated across India, particularly in South Gujarat. Despite its commercial significance, its productivity is severely affected by leaf spot and flower blight caused by Alternaria tenuissima. This study focused on biochemical changes occurring in one resistant variety (Gulzafri Yellow) and one susceptible variety (Punjab Gainda) of marigold following infection. The biochemical parameters analyzed included:
EFFICACY OF FUNGICIDES AGAINST COLLETOTRICHUM GLOEOSPORIOIDES CAUSING STEM END ROT AND FRUIT DROP IN MANDARIN
Mandarin (Citrus reticulata Blanco) is one of India's most important citrus crops, contributing to about 40% of the total citrus cultivation. However, its productivity is severely impacted by stem end rot and preharvest fruit drop, primarily caused by Colletotrichum gloeosporioides. This fungal pathogen spreads rapidly under humid and warm conditions, leading to significant yield losses. The present study was conducted to evaluate the efficacy of various fungicides against C. gloeosporioides using the poisoned food technique in a laboratory setting. Fungal isolates were obtained from diseased mandarin fruits collected from university orchards. Pathogenicity was confirmed using Koch’s postulates. A total of sixteen chemical fungicides were tested for their ability to inhibit mycelial growth. The most effective fungicides at both half dose and recommended dose were:
EVALUATION OF BIOPOLYMER-BASED TRICHODERMA AND ACTINOMYCETES AGAINST WILT AND ROOT ROT COMPLEX OF SAFFLOWER
Safflower (Carthamus tinctorius) is an annual oilseed crop valued for its high-quality oil used in food, cosmetics, and industrial applications. Native to the Mediterranean region, safflower is now widely cultivated, with Maharashtra being a key producer in India. However, its production is significantly impacted by wilt disease, caused by Fusarium oxysporum f. sp. carthami, and root rot, caused by Macrophomina phaseolina, both of which lead to plant mortality, reduced seed yield, and inferior oil quality.This study focuses on the biological management of these diseases using biopolymer-based Trichoderma and actinomycetes. In in vitro experiments, biopolymer-based Trichoderma harzianum exhibited the highest inhibition of Fusarium oxysporum (mean colony diameter: 27.00 mm), followed by Trichoderma harzianum (42.30 mm). Similarly, Macrophomina phaseolina was significantly suppressed by Trichoderma harzianum (29.33 mm) and Trichoderma asperellum (30.33 mm), which performed at par, followed by Trichoderma koningii (34.33 mm) and biopolymer-based Trichoderma harzianum (47.50 mm).Field studies demonstrated that seed treatment with biopolymer-based Trichoderma at 10 ml/kg seed combined with soil application at 100 ml/5 L water per plot significantly reduced wilt and root rot incidence compared to other bioagents.
RECYCLING OF SPENT MUSHROOM SUBSTRATES OF PLEUROTUS SAJOR-CAJU
The present investigation aimed to evaluate the cultivation of Pleurotus sajor-caju on various agro-waste substrates, including soybean straw, wheat straw, paddy straw, sawdust, sugarcane bagasse, banana leaves, bajra straw, and green gram straw. The nutritional composition of these substrates was analyzed before and after mushroom cultivation.Additionally, the study explored the reuse of spent mushroom substrate (SMS) by incorporating it into fresh substrate mixtures at different proportions. Among the tested combinations, 100% soybean straw and 20:80 (SMS + soybean straw) resulted in the highest yield of fresh mushrooms, superior biological efficiency, larger stipe and pileus size, increased pinhead formation, and enhanced fruiting body development. These combinations also required the shortest duration for vegetative and reproductive growth.The findings indicate that spent mushroom substrate can be effectively recycled in combination with soybean straw to support sustainable mushroom cultivation. Spent Mushroom Substrate (SMS) is a valuable by-product with potential applications in organic farming, composting, soil enrichment, biofuel production, and agricultural sustainability. It offers a promising alternative for reducing agricultural waste while enhancing soil fertility and crop productivity.
CULTURAL AND PHYSIOLOGICAL CHARACTERISTICS OF PYTHIUM SPECIES CAUSING DAMPING-OFF OF ACID LIME
The current study was conducted to investigate the effect of culture media, atmospheric temperature, and relative humidity on the growth and development of Pythium deliense causing damping-off in acid lime.A total of six solid culture media—Oat Meal Agar, Corn Meal Agar, Martin's Rose Bengal Agar, V8 Juice Agar, Malt Extract Agar, and Potato Dextrose Agar—were tested for fungal growth. Among these, Oat Meal Agar, Corn Meal Agar, and Martin’s Rose Bengal Agar were found to be the most suitable, with a maximum radial growth of Pythium deliense (90.0 mm), while the least growth was recorded on Potato Dextrose Agar (27.56 mm).The colony characteristics of Pythium deliense varied across media, exhibiting white-colored, evenly thick to sparse growth with floral patterns. The fungus produced aseptate mycelium and globose-shaped sporangia.Physiological studies revealed that the fungal growth significantly varied with different temperature and relative humidity levels. The optimal growth of Pythium deliense was recorded at 25°C and >85% relative humidity.Acid lime (Citrus aurantifolia Swingle) is an important horticultural crop in various regions, including Akola and Amravati districts, where damping-off disease significantly reduces crop yield and quality.
Biological Management of Wilt in Pigeonpea Caused by Fusarium oxysporum f. sp. udum
Pigeonpea (Cajanus cajan L. Millspaugh) is a highly significant legume crop in India, serving as a crucial source of protein. However, the crop is susceptible to a wide array of pathogens, with over 100 known diseases affecting it. Among them, wilt caused by Fusarium oxysporum f. sp. udum is one of the most devastating. An in vitro experiment was conducted to evaluate eco-friendly management strategies against pigeonpea wilt. The study assessed the efficacy of eight bioagents (six fungal and two bacterial) and eight phytoextracts. Among the bioagents, the local strain of Trichoderma asperellum exhibited the highest mycelial growth inhibition (90.26%). Among the phytoextracts, neem demonstrated the highest inhibition at 10% and 20% concentrations (69.56% and 85.11%, respectively), followed by garlic (67.26% and 84%, respectively).Pigeonpea is known for its ability to restore soil fertility by fixing atmospheric nitrogen, enhancing phosphorus availability, and improving soil properties. It is the second most important pulse crop after chickpea in India, particularly in rainfed agriculture. Despite its significance, pigeonpea suffers from several economically important diseases, including sterility mosaic, Fusarium wilt, Phytophthora blight, Macrophomina root rot, Alternaria blight, stem canker, and powdery mildew.In India, wilt incidence ranges from 10% to 60% (Nene et al., 1996), with potential yield losses reaching up to 100% in susceptible cultivars (Pande et al., 2013). In Maharashtra, pigeonpea is primarily grown as a kharif crop on marginal lands by resource-poor farmers due to its resilience against water and nutrient stress. In 2021-22, Maharashtra recorded the highest area (14.18 lakh ha), production (16.49 lakh tonnes), and productivity (1163 kg/ha) for pigeonpea.
BIOCHEMICAL AND MORPHOLOGICAL CHARACTERIZATION OF PSEUDOMONAS FLUORESCENS ISOLATES AND ITS EFFICACY AGAINST DAMPING-OFF IN CHILLI
This study examines three isolates of Pseudomonas fluorescens (PDKV Pf1, Pf2, Pf3) obtained from the chilli rhizosphere, focusing on their biochemical and morphological characteristics and their efficacy in suppressing Pythium aphanidermatum, the causal agent of damping-off in chilli. The isolates were evaluated for their ability to produce hydrogen cyanide (HCN) and indole-3-acetic acid (IAA), essential plant growth-promoting compounds. Morphologically, all isolates were identified as gram-negative and rod-shaped. Among them, PDKV Pf1 displayed the strongest biochemical activity, testing positive for catalase, oxidase, triple sugar iron (TSI), arginine dehydrolase, starch hydrolysis, H₂S production, methyl red test, citrate utilization, HCN production, and gelatin liquefaction.
INFLUENCE OF WEATHER PARAMETERS ON CABBAGE LEAF SPOT DISEASE
Alternaria brassicae, the causal agent of Alternaria leaf spot in cabbage, is one of the most economically significant and widespread diseases in India and worldwide. Since disease progression is highly dependent on weather conditions, a weather-based forewarning system can help farmers implement timely protective measures. A field experiment was conducted during 2023-24 at the Department of Plant Pathology, College of Agriculture, VNMKV, Parbhani, Maharashtra, to assess the influence of weather parameters on the initiation and spread of Alternaria leaf spot in cabbage. The study also aimed to develop a suitable weather-based disease forewarning equation.
STUDIES ON EPIDEMIOLOGY OF CAUSING POWDERY MILDEW OF FENUGREEK
Fenugreek (Trigonella foenum-graecum L.), locally known as “Methi,” belongs to the family Fabaceae. It is an ancient and well-known spice and vegetable crop in India. India is the largest producer of fenugreek in the world, with major cultivation in states like Rajasthan, Gujarat, Haryana, Madhya Pradesh, and Uttar Pradesh.Powdery mildew of fenugreek, caused by Erysiphe polygoni DC, is a significant and serious disease, especially during the flowering and pod formation stages, leading to substantial losses in both grain quantity and quality. Epidemiological studies indicate that the disease typically appears around 52 days after sowing (DAS) during the rabi season. In Navsari district, the disease occurs at moderate to high levels throughout the year. The infection produces a large quantity of inoculum, and in the presence of heavy pathogen load, it spreads across all leaf surfaces, including upper, middle, and lower portions. Weather conditions between the 3rd and 6th standard meteorological week (SMW) during the rabi season play a crucial role in the development of powdery mildew. The maximum and minimum temperatures favorable for disease severity range from 27.6°C to 35.1°C under field conditions. Notably, minimum temperature showed a significant positive correlation with the intensity of powdery mildew infection.
SEED-BORNE INFECTION AND WHITEFLY (Bemisia tabaci) VECTOR INTERACTION IN YELLOW MOSAIC DISEASE IN BLACK GRAM
Black gram (Vigna mungo L. Hepper) is an important pulse crop in India as well as in South East Asia. The main reason for fluctuations in average yield is various biotic stresses, which result in 5–100% yield loss. Among these, Yellow Mosaic Disease (YMD), caused by Mungbean Yellow Mosaic Virus (MYMV), is the most destructive disease of black gram in South East Asia. This disease is transmitted by whitefly (Bemisia tabaci Gennadius) and not by mechanical inoculation or seed. The main objective of the study was to identify the vectors involved in the transmission. The virus was transmitted by whitefly in a persistent manner. Virus-vector relationship revealed that a minimum of five whitefly adults with an acquisition access period of one month and an inoculation access period of five minutes were sufficient to transmit the yellow mosaic disease. The study indicated that the degenerate primers used in the present investigation amplified an approximately 900 bp amplicon of the virus. The percentage detection of the virus from the seed coat, cotyledon, embryo, and whole seed was 100%, indicating the presence of the virus in all tested samples.
ISOLATION, IDENTIFICATION, AND MANAGEMENT OF IN VITRO PHYTOPHTHORA NICOTIANAE, THE CAUSATIVE AGENT OF CITRUS GUMMOSIS
Various Phytophthora species have long been reported to cause different citrus diseases, including gummosis, root rot, fruit brown rot, and citrus decline worldwide, including in India. Among these, Phytophthora nicotianae has gained considerable attention due to its ability to cause citrus gummosis, leading to significant yield losses (approximately 10-30%).Considering this, the present study aimed to isolate the pathogen from infected plants, identify it based on morphological and microscopic characteristics, and evaluate its management using novel in vitro fungicides. The pathogen was isolated from gummosis-infected soil samples using the leaf bait method and exhibited cottony dense mycelium and aseptate hyphae as key morphological characteristics. Fungicide tests revealed 100% inhibition of P. nicotianae at a 2500 ppm concentration under laboratory conditions.
BIOLOGICAL MANAGEMENT OF EARLY BLIGHT OF POTATO
Potato is one of the most well-known vegetables in India. The demand for potatoes is rising because they are nutritious and wholesome, rich in carbohydrates, and contain little fat. Early blight, caused by Alternaria solani and Alternaria alternata, is a widespread disease affecting potato crops globally. The incidence of early blight has been observed extensively in potato-growing areas of Kota district. Chemical control methods are commonly used for managing early blight, but limited work has been done on biological management. Among bio-agents, the results revealed that tuber treatment by spray method with Trichoderma viride @ 8 g/lit per 20 kg, combined with two foliar sprays @ 5 ml/lit of water, was effective against early blight and resulted in better potato yield. This was followed by Pseudomonas fluorescens @ 8 ml/lit per 20 kg of tuber, combined with two foliar sprays @ 5 ml/lit of water, which also showed significant disease control compared to the untreated control.
PHYSIOLOGICAL CHARACTERISTICS OF ASSOCIATED WITH SAPOTA LEAF SPOT NEOPESTALOTIOPSIS PROTEARUM
Characteristics leaf spot disease specimens were collected from a sapota orchard on the university campus and brought to the laboratory, where pathogens isolated using the hyphal tip method and pathogenicity was successfully demonstrated in pot cultures. Neopestalotiopsis protearum was identified as the isolate based on symptoms, cultural, morphological, pathogenicity testing, and molecular analysis. The current study was undertaken to explore the effect of temperature, relative humidity, light, effect and pH level on the growth development and sporulation of N. protearum, the cause of Sapota leaf spot. N. protearum exhibited maximum growth and sporulation at 30°C, with 25°C being the next best temperature. Both 20°C and 35°C exhibited similar impacts on mycelia growth, although 20°C produced more spores. The least growth was observed at 15°C and 40°C. The fungus thrived at 95 percent relative humidity, while 90% also supported good growth. A 12-hour light/dark cycle was ideal for growth, while continuous darkness also aided growth, however, continuous light impeded growth. The fungusfavored a pH of 7.0, but a pHof 6.5 also supporting good growth. Overall, the ideal conditions for N. protearum are 30°C, high humidity(>85%), a 12-hour light/dark cycle, anda pHof 7.0.