Survey of white root rot caused by Dematophora necatrix in apple orchards across six districts of Himachal Pradesh (Shimla, Kullu, Chamba, Sirmour, Mandi, and Solan) was conducted. Data were collected from various locations, documenting the prevalence, disease symptoms, and management practices. Data indicated that disease incidence was in the range of 0.8% to 40%, with the highest occurrence in Rohru (Shimla) and Burwa (Kullu). Wilting, small sized fruits and decayed roots were the commonly observed symptoms on the affected trees. The survey results revealed that orchardists primarily relied on fungicides such as carbendazim, often without following prevenlance of disease, proper application techniques or understanding of disease management. The presence of disease complexes, including co-infections with Phytophthora and Fusarium species, was noted. Findings underscore the urgent need for effective management strategies and better educational outreach for local farmers to mitigate the impacts of white root rot on apple production. The findings of the survey highlights the prevalence of disease in Himachal Pradesh and the kind of symptoms produced.
Losses in wheat yield due to the attack of stripe rust disease caused by Puccinia striiformis f. sp. tritici were assessed under natural field conditions. An experiment was conducted on wheat cultivars having different degree of resistance against stripe rust at three locations continuously for three years in disease prone areas of district Rupnagar, Punjab which is situated in sub-mountainous region of northern India. The infection of stripe rust on cultivar HD 2967 was higher with 80S final rust severity and Area Under Disease Progress Curve (AUDPC) values of 1919 in unprotected plots which caused 72.31% yield reduction. The loss in yield due to stripe rust varied with the resistance level of the cultivar. The correlation coefficient (r) was estimated between wheat yield and disease parameters, revealing a negative correlation. Similarly, net income and the benefit-cost ratio were negatively correlated with disease parameters Final Rust Severity (FRS) and AUDPC, indicating that an increase in disease severity led to greater yield losses and reduced profitability. The relationships between disease parameters and yield components are key factors in guiding the implementation of disease management strategies and assessing their impact on crop productivity and economic returns.
Phytoplasma diseases are common obstacle against vegetable production. Eggplant is one of the major solanaceous vegetable crop which is acutely affected by phytoplasma infection. Little leaf, phyllody and giant calyx are some of the prominent symptoms of phytoplasma infection in eggplant. In present investigation, association of phytoplasma was confirmed with these symptoms by using phytoplasma (16S rRNA gene) specific universal primers (P1/P7). The flower, leaf and calyx tissues of phytoplasma infected plants showing phyllody, little leaf and giant calyx symptoms respectively as well as of healthy plants were fixed in Formalin- Acetic acid- Alcohol (FAA) solution and proceeded for light microscopy. The flower petal, leaf lamella and giant calyx were observed for perceiving microscopic histological changes. The flower and leaf tissues of healthy plants were used as control. In results, it was divulged that phytoplasma infection in eggplant causes many histological wreckings viz., distortion and anarchy of different constitutive cells of dermal, ground and vascular tissues of different plant organs.
Cherry tomatoes are deemed valuable in the market for exotic vegetables and able to fetch a high price in the organic vegetable market. They are becoming increasingly popular for both culinary use and as fresh ingredients in salads. The main obstacles in cherry tomato production in Punjab include late blight in the early spring season and ToLCVD during the rainy season. The aim of the present study was to evaluate the germplasm through artificial inoculation against ToLCVD and late blight disease. Three genotypes against ToLCVD namely PCT-10, PCT-42 and PCT-47 showed symptomless reaction (doesn’t confirm total immunity, but just the absence of symptoms). PCT-60 was highly resistant to late blight, while PCT-9, PCT-11, PCT-13, PCT-29, PCT-42, PCT-46, PCT-51 and Punjab Red Cherry demonstrated resistant reaction against late blight. One genotype PCT-42 exhibited no symptoms of leaf curl and displayed resistance against late blight. These genotypes can be employed in subsequent breeding endeavours to cultivate plants with enhanced resistance to biotic stress.
The present study delved into the integrated management of Alternaria blight, a major threat to marigold (Tagetes erecta L.) cultivation, caused by Alternaria tagetica. The experiment was conducted in the department of floriculture and landscaping, Punjab Agricultural University, Ludhiana during 2022 and 2023. Efficacy of six fungicides and botanicals was evaluated against Alternaria tagetica under in vitro conditions. Tebuconazole+trifloxystrobin gave maximum inhibition (100, 92.22, 89.63, 86.67, 85.56 %) followed by Azoxystrobin (100, 91.11, 82.22,76.67,70.37%),Tebuconazole (100, 90.00, 79.63, 75.19,64.44%),Difenoconazole (100,86.67,78.00,72.96,59.96%) and Metiram (90.74,82.96, 77.80,59.63, 54.45%) at 400,200, 100, 50 and 25 ppm concentration, respectively. Minimum inhibition (69.63, 64.81, 52.22, 37.41,29.26%) was observed in Chlorothalonil at all the five concentrations. Among the six botanicals tested Allium sativum, Azadirachta indica and Moringa oleifera showed strong antifungal activity with 78.89, 69.26 and 67.04 percent respectively at 2000 ppm. Minimum fungal inhibition was observed by Terminalia arjuna (35.14%). Overall, the findings showed the potential of integrated disease management strategies involving fungicides and botanicals to mitigate the Alternaria leaf spot in marigold.
The domestication of wheat paved way to meet the nutritional requirements of the growing world population. However, wheat production is continuously threatened by various biotic stresses , among them the most destructive is yellow rust caused by Puccinia striiformis f.sp. tritici. Fungicide application is an effective mode to manage the disease under high risk conditions. In the present study, different formulations of strobilurins and triazole based fungicides were evaluated against yellow rust, under artificial epiphytotic conditions in field, for two consecutive years. Fourteen fungicidal treatments were used and each treatment was applied twice at 15 days interval starting from the appearance of symptoms. The results showed that all the fungicides significantly reduced yellow rust severity in comparison to untreated check/control. Tebuconazole 430 g/l SC (@ 0.05%) performed best giving almost complete control of yellow rust, followed by azoxystrobin 18.2% w/w + cyproconazole 7.3% w/w SC (@ 0.10%), pyraclostrobin 133 g/l + epoxiconazole 50 g/L SE (@ 0.18%), trifloxystrobin 100g/L + tebuconazole 200 g/L SC @ 0.10% and 0.12%, azoxystrobin 11% + tebuconazole 18.3% w/w SC (@ 0.15%), pyraclostrobin 133 g/l + epoxiconazole 50 g/L SE (@ 0.12%), azoxystrobin 12.5% + difenoconazole 12.5% W/V SC @ 0.14%, and azoxystrobin 23% SC @ 0.10%. Maximum average disease severity of 82.50% and minimum mean yield of 17.54q/acre was observed in control. Hence, any one of these fungicide formulations can be used for irrigated wheat system to effectively manage yellow rust under high disease pressure conditions with attainment of potential yields.
Karnal bunt (KB), caused by Tilletia indica, is a majorquarantine disease of wheat that poses a threat to international trade and grain quality. The deployment of resistant cultivars represents the most sustainable and environment friendly strategy for managing this disease. In this context, the present study involved the systematic evaluation of 972 wheat accessions procured from Indian Council of Agricultural Research - National Bureau of Plant Genetic Resources (ICAR-NBPGR) in three consecutive cropping seasons (2019-20 to 2021-22) to identify stable sources of KB resistance. The test material was screened artificially at boot leaf stage using syringe inoculation method at Punjab Agricultural University, Ludhiana. Among the 972 accessions, 31.07% accessions consistently showed complete resistance with zero percent KB infection, while 11.83 % accessions demonstrated resistance response with KB infection levels ranging from 0.1 to 5.0 percent across all the three screening years. These resistant accessions will be crucial genetic pool for breeding programs, enabling gene pyramiding for multiple disease resistance to reduce fungicide dependence for sustainable wheat production. This study highlights the role of systematic screening for gene bank resources for the identification of durable resistance sources.
Sheath blight caused by Rhizoctonia solani is one of the most destructive diseases limiting rice productivity. This study evaluated the efficacy of seven fungicide formulations viz., mancozeb 50% + thiophanate methyl 25% WG; kasugamycin 5% + copper oxychloride 45% WP; azoxystrobin 5.1% + tebuconazole 9.1% + prochloraz 18.2% EC; fenoxanil 5% + isoprothiolane 30% EC; azoxystrobin 14 % + epoxiconazole 9 % SC ; picoxystrobin 7.05% + propiconazole 11.7% SC and tebuconazole 50%+ trifloxystrobin 25% w/w WG under artificial epiphytotic field conditions during kharif season of 2023 and 2024 at Punjab Agricultural University, Ludhiana. Among these, tebuconazole 50% + trifloxystrobin 25% @ 0.4g/L demonstrated highest efficacy, recording the lowest mean disease severity (12.78%) with the highest per cent disease control (84.25%) and significant increase in grain yield (36.60%) over the control. Picoxystrobin 7.05% + propiconazole 11.7% and azoxystrobin 14% + epoxiconazole 9% SC also showed promising results in both disease suppression and yield enhancement. A strong negative correlation (r = -0.95) was observed between disease severity and percent yield increase, highlighting the critical role of effective sheath blight management in improving rice productivity.
Charcoal rot caused by Macrophomina phaseolina, is an important fungal disease of sesame crop. Inoculation techniques were standardized to evaluate the sesame germplasm against M. phaseolina. Four different inoculation techniques were evaluated, in which two soil inoculation methods viz. infected sorghum grain inoculum and maize sand-meal medium inoculum and two stem inoculation methods viz., tooth pick culture technique and stem cut inoculation were compared. Toothpick inoculation method was observed more convenient and effective for screening of large set of sesame germplasm. Total 54 germplasm lines were screened along with the two checks namely PB Til No. 2 and RT-346. Six-week old sesame plants were inoculated with toothpick method and out of 54 lines screened against charcoal rot, four accessions viz., IC131797, IC129637, IC0383343, and IC130030 showed a resistant reaction.
Leaf rust caused by Puccinia triticina (Pt) is one of the most dangerous diseases of wheat and has led to significant yield losses worldwide. Due to the constant evolution of pathogen population, the resistance often breaksdown. Therefore, to match the pathogen evolution, extensive research is needed to widen the gene pool and for gene pyramiding. In this context, the present study was aimed to identify and characterize leaf rust resistance genes from the European winter wheat collection using the two most prevalent Pt pathotypes (77-5 and 77-9). Race-specific seedling assays and field evaluation were carried out at two different hot spot locations (Ludhiana and Langroya) in Punjab, India. Based on seedling response against each pathotype the germplasm was categorized into resistant (Infection type (IT)<3) and susceptible (IT >3). Out of 374 lines, 14 and 7 lines were resistant against pathotypes 77-9 and 77-5, respectively and 6 lines viz. Grisby, Hamac, Mandub, Timber, Tulsa and Winnetou showed resistance reactions against both the pathotypes. Under field conditions, 6 lines (Grisby, Hamac, Mandub, Timber, Tulsa, and Winnetou) showed highly resistant responses (AUDPC=0) at both the test locations, i.e. has showed all-stage resistance. Some of the lines showed adult plant resistance (AUDPC=1-200) as these were susceptible at the seedling stage. The identification of Lr genes present in these lines was done by using differentials and molecular markers tagged with effective Lr genes under North-Indian conditions. A total of eight Lr genes tagged markers (Lr9, Lr19, Lr24, Lr28, Lr37, Lr42, Lr58 and Lr76) were used. The presence of Lr19, Lr24, Lr28, Lr58 and Lr76 was confirmed. The resistant germplasm identified can be deployed in leaf rust resistance breeding programs to broaden the genetic basis of leaf rust resistance.
Southern corn leaf blight (SCLB), caused by Bipolaris maydis (Syn. Helminthosporium maydis), is a serious fungal disease of maize throughout the world where maize is grown under humid and warm conditions. Present investigation was carried out to identify the factors which influences the progression of disease. During the assessment of infection level in maize plants of different ages, it was revealed that 50 days old plants were found most susceptible, when pathogen culture of different age was evaluated on maize plants, it was recorded that 14-days old culture had highest potential for infecting the plants. First and third sub-cultures of pathogen exhibited highest per cent disease index. Conidial germination of the pathogen was also checked at different incubation periods (4 to 36 hours), and it was found that maximum conidial germination (67.46%) occur after 36 hours of incubation.
Screening of fifteen germplasm lines collected from different sources against tomato leaf curl disease under field conditions was done. Two lines, Mahaveer and Avinash-2 were found resistant. Samrudhi F1 and Namdhari 82535 were found moderately resistant while other eleven lines viz. Heem Sohna, Sonali, Rupali, NS 816, NS 812, Pusa Ruby, Indus 1030, Arti, DVRT-2, Hybrid no. 15 and Local were susceptible. Different insecticides (imidacloprid, thiamethoxam, dimethoate, acetamiprid, profenofos and oxy-demeton methyl) were also evaluated against tomato leaf curl disease on cv Pusa Ruby under field conditions. The results showed that seed treatment+ seedling dip + foliar application with imidacloprid showed lowest disease intensity of 8.14% as compared to untreated control.
Fusarium ear rot (FER) caused by Fusarium verticillioides holds economical significance in maize due to its potential for mycotoxin contamination, which poses risk to the health of both humans and animals. Under Punjab conditions, FER poses a persistent threat to maize cultivation in spring and Kharif sown maize, thus significantly impacting crop yield and quality. In the present study, twenty isolates of Fusarium species associated with maize ear rot were collected from different maize growing areas of Punjab. The virulence spectrum of these isolates was studied on maize hybrid PMH 2 during spring 2022 and Kharif 2022 under field conditions. In the spring season, FER severity ranged from 35.16 to 75.88 per cent, while during Kharif season it varied from 52.75 to 80.50 per cent. On an average, ear rot severity was notably higher during the Kharif season (67.01 %) compared to the spring season (56.42 %). The presence of highly aggressive isolates resulted in higher mean ear rot severity of 70.17 per cent during Kharif season, as opposed to 66.40 per cent during the spring season. Additionally, the frequency of highly aggressive isolates was 80 per cent during the Kharif season, whereas, it was 40 per cent during the spring season. Weather conditions, including a temperature of 28°C, relative humidity of 67.13 per cent and total rainfall of 286 mm during the Kharif season’s reproductive stage, were found to be conducive to FER development. These results imply that the Kharif season, characterized by favourable environmental conditions, is best suited for screening germplasm against FER.
The present investigation was undertaken to develop an effective and ecofriendly strategy for the management of root rot disease of pea (Pisum sativum L.), which is widely prevalent in moderate to severe form in different parts of the country. It is assuming the status of major disease mainly in south-west zone of Haryana. The diseased plants show poor growth, yellowing and drying of foliage with partially or fully damaged root system. The pathogen associated with this disease was identified as Fusarium solani f.sp. pisi (Jones) Synder and Hansen. Keeping in view the importance of this disease, the study was undertaken to integrate different management strategies likefungicides, phytoextracts, organic amendments and bio-agents. The integration of organic amendment+ seed treatment with fungicide, botanical and bio-agent (Captan 2 gm/ kg seed + Neem oil @ 0.3% + T. harzianum @ 10gm/kg + Mustard cake @ 50gm/sqm) was found superior in minimizing root rot incidence of pea (4.3%) followed by seed treatment with fungicides + botanicals+ bioagent (Captan 2 gm/ kg seed + Neem oil @ 0.3% +T. harzianum @ 10gm/kg) with the disease incidence of 4.7% in comparison to maximum root rot incidence of 14.3 % in the untreated control.
Sheath rot of rice has become an emerging disease in most of the rice-growing areas of north India, so the resistant varieties against sheath rot need to be developed. An effort was made to identify resistance sources against the disease caused by three different pathogens viz., Sarocladium oryzae, Fusarium verticillioides, and Fusarium fujikuroi in the region. Fifty advanced promising rice germplasm lines were inoculated with three pathogens associated with disease using the grain insertion method at the boot stage. Two lines RYT 3836 and RYT 3920 showed moderately resistant reaction to all three pathogens inoculated. RYT 3886 was resistant to both F. verticillioides & F. fujikuroi while RYT 3884 was resistant to F. fujikuroi only. However, none of the evaluated lines possessed resistance for S. oryzae.
The progression of aonla rust disease was studied on two susceptible aonla cultivars viz., NA-7 and Chakaiya during the winter season of 2020-21. The disease severity was observed to be highly influenced by the variation in the temperature and relative humidity. A correlation matrix was developed to analyze the role of prevailing weather conditions on disease development. The disease severity was significantly and negatively correlated with average maximum temperature and exhibited significant and positive correlation with morning and evening relative humidity. Wind speed also played a significant role in disease progression as rust of aonla is an air borne disease. Multiple regression analysis was carried out which revealed the role of weather parameter in aonla rust development with R2 value of more than 0.92. AUDPC value on Chakaiya was more i.e 1555.26 as compared to cultivar NA-7 (1407.77) which indicated the faster disease progression and susceptibility of the cultivar Chakaiya over NA-7. This study can be used further to develop a disease forecasting module for aonla rust.
Angular leaf spot of common bean, caused by the hemibiotrophic fungus Pseudocercospora griseola, is one of the most widely distributed and damaging diseases of common bean, resulting in yield losses up to 80 per cent. Successful culturing of P. griseola is pre-requisite to conduct the experiments for development of management strategies against the disease, but isolation of P. griseola is difficult as pathogen is slow growing and generally dominated by saprophytes. To address this issue, different isolation techniques were evaluated for the successful isolation of P. griseola from infected leaf samples. Four different methods viz., the use of infected leaf bits sterilized toothpicks, moist chamber technique and picking up synnemata from diseased samples were evaluated and among them, picking up synnemata from infected leaves was found most efficient with 58.0 per cent recovery efficiency followed by moist chamber technique with 40 per cent recovery efficiency.
White rot of brinjal caused by Sclerotinia sclerotiorum (Lib.) de Bary has become a serious problem in India since last few successive years. This disease can cause significant yield losses if not managed well in time with effective management strategies. This study was conducted with an aim to evaluate the efficacy of various fungicides against S. sclerotiorum under in vitro as well as field conditions. All the tested fungicides significantly inhibited the mycelial growth and lowered the disease severity under field conditions as compared to the control. The complete mycelial inhibition was observed in Nativo (tebuconazole + trifloxystrobin) 75WG at 75 & 100 ppm concentrations and Bavistin (carbendazim) 50WP at 100 ppm concentration. The propiconazole was found least effective in checking the growth of the pathogen. Under sick plot conditions, the fungicides Nativo (tebuconazole + trifloxystrobin) 75WG and Bavistin (carbendazim) 50WP performed best with lowest disease severity and higher yield, very closely followed by Score (difenoconazole) 25EC.
Excessive application of copper-based fungicides has led to concerns over soil contamination and its long-term ecological effects. This study evaluates the impact of the copper hydroxide-chitosan-Trichoderma (Cu-Chi-Tri) consortium on copper residue accumulation in soil, using elemental analysis through Scanning Electron Microscopy with Energy Dispersive X-ray spectroscopy (SEM-EDX). After two consecutive years of Cu-Chi-Tri application for late blight management in potato, the elemental analysis of the soil samples revealed a significantly lesser accumulation of copper residue under consortia application, whereas substantial Cu accumulation was detected in soil where Cu(OH)2 alone was utilised for the late blight management. The findings suggest that integrating chitosan and Trichoderma with a reduced Cu (OH)2 dose minimizes residual accumulation, thus offering an ecofriendly strategy for disease management with long term prospect of soil health and sustainability.
