Minimum Disease Severity Research Articles

Impact of Weather Parameters and Time of Sowing on Severity of Powdery Mildew in Cluster Bean

Background: Powdery mildew of cluster bean causes considerable yield loss upto 50-55%. Studies carried on cluster bean powdery mildew are very few and as such there is no information related to epidemiology of the disease. Environmental factors decide the epidemic of the disease and are being used to forecast the disease severity. Methods: Five different dates of sowing of cluster bean were evaluated in a randomized complete block design with four replications at Main Agricultural Research Station, College of Agriculture, Dharwad. Observations on the first appearance of the disease and severity were recorded at weekly intervals using disease scoring scale 0-9 and along with pod yield were considered for statistical analysis. The weather data was used to correlate with the disease severity and correlation matrix was worked out. Further, the observations were converted to % disease index to calculate rate of infection and area under disease progress curve (AUDPC) for each date of sowing. Result: Sowing of crop in first fortnight of September recorded the minimum mean disease severity of 19.10% and recorded pod yield of 4.72 t/ha with lower value of area under disease progress curve (1270.50) as against crop sown in first fortnight of November that recorded the 39.39 % of maximum mean disease severity, 3.82 t/ha pod yield and 2583.88 of area under disease progress curve. The mean maximum temperature was positively correlated (0.89) with % disease index whereas, minimum temperature (-0.87), morning relative humidity (-0.81) and evening relative humidity (-0.88) were negatively correlated with % disease index. Disease progression was started at 35 days after sowing and the maximum ‘r’ value of 0.157 was observed during the II fortnight of September followed by an ‘r’ value of 0.142 during the I fortnight of September whereas, a lower ‘r’ value of 0.009 was observed in I fortnight of September sown crop at 63-69 days after sowing.

Impact of Cultural Practices and Nitrogenous Fertilizer on the Development of Brown Spot Disease of Rice

Among the diseases the brown spot disease of rice caused by Bipolaris oryzae is most dominant fungal disease of rice after blast (Pyricularia oryzae) which is causing losses in the yield which resulted in instability in rice production particularly in north Bihar. This disease was considered to be one of the most important facet of 1943 Bengal Famine. The losses in famine were accounted to 50-90 per cent (Ghose et al. 1960; Padmanabhan, 1973). The disease is a serious and has global distribution and it has been found in all rice growing countries in Asia, America and Africa. The studies mainly adhered to see the effect of various doses of nitrogen and different cultural practices on development of brown spot disease of rice. Among the various cultural practices, minimum (17.64%) disease seventy and maximum yield (3.13/ha) were found with application of FYM (5 t/ha) + line sowing of 60 kg seed/ha + 50% N application after 15 DAS 25 % N at maximum tillering + 25% N at panicle initiation + weed control. Doses of nitrogen were positively related with the disease development and negatively related with the grain yield indicating the maximum (38.30 % and 39.0 %) disease severity and minimum (1.86 and 1.97 t/ha) grain yield with nitrogen dose of 120 kg/ha. In respect of varietal response, the minimum (12.10 % and 16.40 %) disease severity and the maximum (4.34 t/ha and 4.58 t/ha) yield were recorded in the variety Rajshree receiving 80 kg N/ha.

Biophysical factors and agronomic practices associated with Fusarium ear rot and fumonisin contamination of maize in multiple agroecosystems in Ethiopia

AbstractIn Ethiopia, Fusarium ear rot (FER) reduces yield, quality, and safety of maize and negatively impacts the economics of maize growers. However, there is almost no published information on geographic distribution, severity, or causal agents of FER in Ethiopia or levels of preharvest fumonisin contamination, biophysical factors, and agronomic practices associated with FER. Therefore, we surveyed 480 agricultural fields located in 10 Ethiopian zones to assess the incidence and severity of FER as well as agricultural practices and biophysical factors associated with each field. We also determined the concentration of fumonisin in samples taken from the fields. Results revealed that FER was prevalent with varied disease intensity and yield loss levels among the assessed zones. The highest percent severity index (PSI) was recorded in Mirab Wellega (33.2%), with a correspondingly maximum estimated mean grain yield loss of 13.6%, while the minimum disease severity 11.3% and yield loss 5.4% were recorded from the Ilubabor zone. Fumonisins (FB1, FB2, FB3, and FB4) were detected in 98% of the samples, and the levels ranged from 5 to 7517 μg kg−1 (mean, 540 μg kg−1 and median 82.4 μg kg−1). The mean fumonisin contamination of 1524.4, 1316.8, 744.5, and 742.6 μg kg−1 was recorded for Mirab Welega, Misraq Wellega, Assosa, and Hawassa zones, respectively. In total, about 11.3% of the maize samples exceeded the maximum tolerable total fumonisin limit set by the European Union in maize flour (>1000 μg kg−1) and are not suitable for human consumption. Disease severity highly significantly (p < 0.0001) correlated with biophysical factors such as insect infestation (r = 0.60, p < 0.0001) and weed infestation (r = 0.64, p < 0.0001) and agronomic practices such as nitrogen phosphorus sulfur fertilizer application rate (r = −0.39, p < 0.0001) and insecticide spray frequency (r = −0.55, p < 0.0001). Other agronomic practices such as earlier or later sowing date and inter‐cropping systems significantly reduced (p < 0.001) FER incidence, PSI, and the associated grain yield loss. There was significant (p < 0.0001) variation among maize cultivars currently under production in reaction against FER disease intensity. Moreover, the result of the present study attests a strong positive association (p < 0.001) between disease intensity and maize fumonisin concentrations. Generally, the study revealed a wider distribution of FER and fumonisin contamination of maize in the southwest major maize‐growing belts of Ethiopia. Thus, appropriate integrated pre‐harvest ear rot management strategies including the use of resistant cultivars and suitable agronomic practices are recommended for the management of FER and the associated mycotoxins in Ethiopia.

Silicon Supplements Potentially Reduce the Sheath Blight Incidence and Severity of Rice (Oryza sativa L.)

Sheath Blight is a disease causing up to 50% yield losses of rice depending on severity. Silicon (Si) is a beneficial nutrient for rice having the ability to protect against diseases. So, a pot experiment was carried out at the Bangladesh Institute of Nuclear Agriculture Headquarters Farm, Mymensingh from July 2021 to November 2021 with artificial inoculation of Rhizoctonia solani to study the effect of different Si supplements and their doses on rice ShB incidence and severity. The test crop used in the study was Chinigura aromatic rice variety. The experiment was laid out in a completely randomized design (CRD) with three replications. Among the nine treatments, except control, Si was applied from K2SiO3, CaSiO3, and MgSiO3 with three concentrations viz., 2, 4, and 6 mM Si respectively through the foliar spray. The application of different Si supplements showed a significant positive effect on the growth, yield contributing characters, and yield of rice. The highest yield was found at the application of Si as CaSiO3 6 mM. Disease incidence and severity matrix were significantly reduced due to the application of different Si supplements. The minimum disease incidence and severity matrix were found at T6 (CaSiO3 6 mM) treatment. The maximum disease incidence and severity matrix reduction was 35.27% and 54.3%, respectively at T6 (CaSiO3 6 mM) treatment over control (without Si application) which was statistically identical to T3 (K2SiO3 6 mM), T7 (MgSiO3 2 mM), and T8 (MgSiO3 4 mM). The overall disease incidence and severity matrix reduction over control was 24.68% and 35.59%, respectively due to different Si supplement applications. Again, the highest nutrient concentration was found in different Si supplement treatments over control. So, Si supplement applications such as K2SiO3, CaSiO3, and MgSiO3 may be an advisable option for the management of sheath blight disease of rice for successful crop production.

Screening of Advanced Germplasm against Ascochyta rabiei and its Management

Ascochyta blight is caused by Ascochyta rabiei, one of the most prevalent chickpea diseases worldwide. Losses could reach as high as 100%, and this damage could significantly affect both seed quality and production. The most effective way for the management of this disease is genetic resistance. Seventeen chickpea varieties/lines were screened against a virulent isolate of Ascochyta rabiei in controlled environmental conditions. Advance Line-2, Bittle-2016, and Noor-2009 within the germplasm exhibit a moderately resistant reaction. TG-1415 and Advance Line-1 demonstrate a moderately susceptible response. On the other hand, Noor-2013, Star-Channa, and Rohi display a highly susceptible response. In the poisoned food technique among applied treatments at 50 ppm, Diphenoconazole proved be best, with a 46% reduction in the growth of the pathogen, followed by propiconazole and Azoxystrobine+Diphenoconazole with 45.5 % and 45%, respectively. In the mean while in glasshouse evaluation at 50ppm, Diphenoconazol proved best with a minimum disease severity of 24%, followed by propiconazole and Metalaxyl with a 25.9% and 27% reduction in disease severity, respectively.

Management of seed borne inoculum of Xanthomonas cucurbiate causing bacterial leaf spot of pumpkin and bottle gourd

Bacterial leal spot is a common and destructive disease of cucurbits. Recent research revealed the seed borne nature of Xanthomonas cucurbitae. In this study, seeds wrapped in muslin cloth were dipped in various treatments involving hot water and chemicals. Hot water treatment of seeds at 55°C for both pumpkin and bottle gourd isolates resulted in minimum (28.73 and 23.33%, respectively) seedling infection. In vitro evaluation of fungicides and antibiotic (streptocycline) by using paper disc method revealed that Bordeaux mixture and copper oxychloride to be most effective against pumpkin and bottle gourd, respectively. Under chemical seed dip treatments, the minimum number of infected seedlings were recorded with streptocycline (37.64%) and copper oxychloride (40.80%) for pumpkin and bottlegourd, respectively. For both the isolates, maximum seed germination was recorded in seeds treated for 720 minutes (98.20 and 98.60%, respectively). A combination of streptocycline and copper oxychloride as seed treatment for three hours gave best results for both the isolates (16.33% and 15.67%, respectively). Under pot house conditions, combining streptocycline (100 ppm) and copper oxychloride (3000 ppm) as a seed dip treatment for three hours was found to be the most effective. The recorded minimum disease severity was 18.00 and 22.00%, respectively.

Evaluation of Chili Germplasm against Leaf Spot and its Management by Nutrients and Fungicides

Chili (Capsicum annum L.) is a widely grown vegetable in tropical and subtropical areas that is attacked by a diverse range of bacterial and fungal pathogens, causing severe yield and quality losses. Alternaria leaf spot, caused by Alternaria alternata, is the major fungal disease of chili that deteriorates the vitality of the crop. The objective of the current research is to identify the most effective nutrient combination and fungicide against Alternaria leaf spot disease and to evaluate resistant sources. The current research was conducted using six varieties (CH-121, Chilli-900 F1, Red Wing, SAYBAN, AAHP-1, and Diamond CH-121) collected from Ayub Agricultural Research Institute, Faisalabad, Pakistan. Seeds were sown in the Plant Pathology field area, University of Agriculture, Faisalabad, to screen against leaf spot disease. The effect of different fungicides and nutrients to overcome chili leaf spot was studied, and three treatment combinations were prepared: (ZnSO4 (ZS) + MnSO4 (MS) + boric acid (BA) + Topsin M), (ZS + MS + BA + Mancozeb), and (ZS + MS + BA + Vitavax). Among these, the combination of (ZS + MS + BA + Vitavax) was the most effective against leaf spot disease. Minimum disease severity was observed with ZS + MS + BA + Vitavax in CH-121 (15.00), while maximum disease severity was observed with the control in Red Wing (93.67). Environmental data were collected and statistically analyzed. There was a significant (p 0.05) but positive correlation between maximum temperature, minimum temperature, wind speed, rainfall, and disease severity. There was a negative correlation between relative humidity and disease severity. In conclusion, micronutrients were found to enhance Alternaria leaf spot tolerance in chili plants, providing a cost-effective and easily obtainable solution. The combined use of nutrients and fungicide is effective in preventing the development of resistance in pathogens against fungicides.

Biological control of fruit rot of postharvest orange (Citrus aurantium) by aqueous plant extracts

Post-harvest rot symptoms caused by complex airborne fungi are nowadays the most serious threatening disease affecting orange fruits in Nigeria and presumably in many African countries. Experimental trials were conducted at the Department of Biological Sciences (Akwa Ibom State, Nigeria) from January to December 2022 to ascertain the pathogens associated with postharvest fruit rot of oranges (Citrus aurantium L.). Results of the pathogenic test revealed that Fusarium sp. and Penicillium sp. are pathogenic and produced the highest lesion diameter (38.67 and 40.33 mm, respectively) and disease severity index (88.67 and 94.33%, respectively). The frequency occurrence of Fusarium sp. (69.14%) and Penicillium sp. (50.62%) was the highest. Two aqueous extracts of Azadirachta indica Juss. leaves and Zingiber officinale Roscoe rhizomes (at 80% concentration) were evaluated for their antifungal activities against the pathogenic isolates under in vitro and in vivo conditions. The results revealed that A. indica and Z. officinale aqueous extracts exhibited the highest mycelial growth inhibition (>90%) of Fusarium sp. and Penicillium sp. Similarly, under in vivo assay minimum lesion diameter (≤ 6.37 mm) and disease severity index (≤11.13%) were recorded in these aqueous extracts. In conclusion, the application of A. indica and Z. officinale can provide an alternative to fungicides against Penicillium sp. + Fusarium sp.

Gamma irradiation with modified atmosphere packaging extend shelf life of mangoes cv. Himsagar

Irradiation technology has been in use to prolong shelf life and reduces postharvest losses of agricultural produce in many parts of the world as a safe and commercial option for its high efficacy and safety. The research was carried out at the Postharvest Laboratory of Horticulture Division, BINA during the period from June to July 2021 following completely randomized design (CRD) with three replications of 8 fruits per replication. The preharvest bagged and unbagged mangoes (cv. Himsagor) were collected from Bagha Upazila of Rajshai District. Different doses of gamma irradiation (0, 200, 400, and 600 Gy) were applied, and the irradiated mangoes were wrapped in polypropylene (PP) bags of 35μ thickness along with a control treatment to evaluate shelf life and quality at ambient condition. Parameters investigated were colour, texture, TSS, weight loss, disease incidence, disease severity, and vitamin C content during the period of storage. In terms of combined effect of preharvest bagging and gamma irradiation at the 12th day after storage, the minimum weight loss (3.92%), disease incidence (11.00%) and disease severity (8.61%) were found from pre-harvest bagged mangoes when irradiated @ 400 Gy and wrapped in PP bags. In contrast, the maximum weight loss (18.18%), disease incidence (80.00%) and disease severity (74.67%) were found from the preharvest non-bagged and non-irradiated mangoes that were not wrapped. The findings would greatly contribute in reducing postharvest loss of mangoes and maintain their quality during marketing at ambient condition.
 Bangladesh J. Nuclear Agric, 37(1): 11-22, 2023

Integrated approach for the management of common bean rust (Uromyces appendiculatus) under field conditions

A field experiment was conducted to test the efficacy of different management practices and fungicide application timings for common bean rust management in Chitwan, Nepal. It was conducted in a randomized complete block design (RCBD) with two factors: management practices (Azoxystrobin, Trichoderma viride, maize intercropping + Trichoderma viride, Neem + Garlic extracts, and inoculated and untreated controls) and fungicide application timings (8 days after inoculation and 3 days after inoculation), each with three replications. The minimum disease severity was found with azoxystrobin, which was at par with neem + garlic extract and maize intercropping + Trichoderma at 50 days after inoculation (DAI). The maximum number of rust pustules per cm2 was observed in the control plots (7.56), followed by Trichoderma (4.79) at 50 DAI. The maximum necrotic colonies (%) were observed with the control (36.88%), followed by Trichoderma (25.15%), while the effects of other treatments were at par at 40 DAI. Maize intercropping with Trichoderma resulted in a maximum plant height (201.56 cm), which was at par with azoxystrobin (197.81 cm). The plants treated with azoxystrobin showed maximum green pod yield at one picking (2411.35 g) which was at par with maize intercropping + Trichoderma and neem + garlic extracts. Rust was controlled more effectively when the fungicides were sprayed at 4 DAI than 8 DAI. The maximum disease control was observed with Azoxystrobin; however, as other treatments also had comparable effects, an integrated approach could be adopted for the sustainable management of common bean rust.

Management of Alternaria Leaf Blight (Alternaria cucumerina var.cyamopsidis) in Cluster Bean Through Fungicide Application

Background: Clusterbean [Cyamopsis tetragonaloba (L.) Taub] commonly known as ‘guar’ means ²cow food² is an annual arid and semi-arid legume crop belonging to the family leguminaceae. Methods: Two field experiment were conducted during 2019-2021 to find out the most effective fungicide for the management of Alternaria leaf blight in Cluster. Seven fungicides viz., Tebuconazole 250 EC @ 0.1%, Difenconazole 25 EC @ 0.1%, Hexaconazole 5 EC @ 0.1%, Propiconazole 25 EC @ 0.1%, Chlrothalonil @ 0.2%, Trifloxystrobin 50% WG@ 0.1%, Mancozeb 75% WP @ 0.2% were evaluated for their efficacy aganist cluster bean Alternaria blight. Result: In the year 2019 during Kharif season the foliar spray with Tebuconazole 250 EC @ 0.1% was found to be the most effective fungicide at initiation of flowering and at pod stage with minimum disease severity (9.87 and 12.00%) and the maximum seed yield and straw yield of 2077 and 3994 kg/ha, respectively. During Kharif-2020 same trends was observed with Tebuconazole 250 EC @ 0.1% in reducing the severity of the disease foliar spray of Tebuconazole also recorded the highest B: C ratio of 4:5 and 4.73 during 2019-20 and 2020-21 respectively.

Antifungal activity of essential oil and emulsifiable concentrates of citronella and lemon grass against Phomopsis vexans

The present study aims to develop eco-friendly Emulsifiable Concentrates (EC) using citronella and lemon grass essential oil (EO) and evaluate its antifungal activity against Phomopsis vexans in Solanum melongena. Among nine prepared formulations, F1 formulation with EO (40%) + vegetable oil (50%) and emulsifier blends (10%) with hydrophilic-lipophilic balance value (12.86) were found suitable for both EO formulations. These formulations (CF1 and LF1) performed well in terms of emulsion stability, cold test, accelerated storage and foam test indicating feasibility for their commercial production. In laboratory studies, at 0.1% concentration, citronella essential oil, lemon grass essential oil and their EC formulations CF1 and LF1 inhibited the growth of P. vexans with EC50 values 0.0087, 0.0098, 0.009 and 0.0126, respectively. Further, under field conditions, CF1 performed better than LF1 formulation in terms of minimum disease severity (32.22%). Hence, EC formulations can be used as natural and eco-friendly fungicide for P. vexans control.

Comparative Study of Fungicides, Bio-Agents and Organic Amendments for Management of Black Scurf of Potato

Potato (Solanum tuberosum L.) is an important staple food crop of the world. India rank 2nd after China producing 52588.98 thousand metric tons potato per year. In India, among all the states Uttar Pradesh stands first with the production of 15812.62 thousand metric tones followed by West Bengal with the production of 12782.00 thousand metric tons in the year 2018-19. Potato is infected by a number of soil and tuber borne diseases and pest. Among all, black scurf (Rhizoctonia solani Kuhn.) is a destructive disease of potato. The most common phase of this disease is formation of sclerotial masses on the tuber resulting in black scurf which considerably reduces market value of edible tubers. In present investigation different bio-agents and chemicals were tested for management of the disease were used under field conditions. Among the bio-agents, Trichoderma harzianum, Chaetomium globosum, Bacillus subtilis, with vermicompost. Fungicides, Boric acid @ 3%, Carbendazim 50% WP @ 1%, Mencozeb @ (0.2%) and Pencycuron @ (0.2%) concentration. In field experiment the result revealed that the minimum disease incidence was recorded (12.00%) in Mancozeb @ 0.25% foliar spray compared to untreated check 60.00% and minimum disease severity (18.96%) and maximum yield 275.00 q/ha was recorded in Boric acid @ 3% tuber treatment compared to untreated control.

Integrated Management of Purple Blotch Disease of Garlic (Allium Sativum L.)

Purple blotch (Alternaria porri) is one of the major diseases of garlic causing huge loss to the growers. An investigation was undertaken to formulate suitable management practices against purple blotch of garlic var. DWG1. Among the various treatments, seed treatment with Trichoderma harzianum @ 10 g/kg of cloves and two foliar applications of fluopyram 17.7% + tebuconazole 17.7% @ 0.1% on 50 and 65 days after sowing recorded the minimum disease severity (13.34 PDI) and higher bulb yield (5.77 t/ha), 10 bulbs weight (83.00 g), number of cloves (15.67) and 100 cloves weight (65.33 g) with C:B ratio of 1: 3.51. The combined application of cow urine, nimbecidine and Trichoderma harzianum also showed significant impact on disease reduction as well as on yield of garlic. However, fluopyram 17.7% + tebuconazole 17.7% showed a higher benefit with minimum production cost and this approach is proposed to garlic growing farmers to mitigate the purple blotch disease. Bangladesh J. Bot. 52(2): 291-295, 2023 (June)

Evaluation of new generation molecules against frogeye leaf spot and pod blight disease in soybean under field condition

In this study, bio-efficacy of new generation fungicides Picoxystrobin 7.05%+Propiconazole 11.71%, Propiconazole 25 % EC, Picoxystrobin 22.52% SC, Pyraclostrobin 20% WG and Hexaconazole 5% EC against frogeye leaf spot and anthracnose/pod blight disease of soybean were evaluated under field conditions. Pooled results revealed that combination of two fungicide Picoxystrobin 7.05%+Propiconazole 11.71% w/w SC @ 1000 ml/ha resulted in minimum disease severity (7.0 and 3.4%) as well as maximum (71.3 and 77.6%) disease management of frogeye leaf spot and anthracnose/pod blight disease in soybean, respectively. However, it was found to be significantly at par with the same fungicide applied with higher dose @ 1125 ml/ha. Maximum seed yield (23.18q/ha) was recorded with the treatment Picoxystrobin 7.05% +Propiconazole 11.71% w/w SC @ 1000 ml/ha which was on par with the spray of higher dose of same fungicide @ 1125ml/ha. However, minimum yield (17.18q/ha) was recorded in untreated control.

Estimation of Biocidal Potential of Desert Phytopowders for the Management of Citrus Canker

Citrus is one of the most important fruit crops, throughout the world. It is a rich source of antioxidants and vitamin C. Citrus canker is a potential threat to its successful production. In current study, ten desert phytopowders including Xanthium strumarium, Dipterygium galucun, Leptadenia pyrotechnica, haloxylon recurvum, Suaeda fruticosa, Salsola baryosma, Citruluscolocynthis, Abutilon indicum, Aerva javanica, and Calotropis procera at three different concentrations (5.0, 7.5 and 10.0%) were evaluated under in vitro conditions against Xanthomonas citri pv. citri. Among all phytopowders, X. strumarium and S. fruticosa, showed maximum inhibition zone (40 mm) followed by S. baryosma(38.50 mm) C. colocynthis(37 mm), Abutilon indicum(34 mm), H. recurvum(32 mm), D. galucun (30.5 mm), A. javanica, (29.50 mm), L. pyrotechnica, (29.5 mm) and C. procera (28 mm) as compared to control. Then, effective phytopowders were applied under greenhouse and field conditions @ 5.0, 7.5 and 10.0% against citrus canker. Combination of X. strumarium + S. baryosma showed minimum disease severity (22%) followed by X. strumarium (26%), X. strumarium + S. fruticosa (27%), S. fruticosa (27%), X. strumarium + S. baryosma (27%), and S. baryosma (29%) as compared to control. While in field experiment, the combination of X. strumarium + S. fruticosa showed significant results with minimum disease severity (32%) followed by S. fruticosa + S. baryosma (32%), X. strumarium + S. baryosma (33%), S. baryosma (35%), X. strumarium (36%) and S. fruticosa (36%) as compared to control. It is concluded that application of X. strumarium + S. baryosma phytopowders will be helpful for farmers to combat citrus canker.

Efficacy of different combinations of microbial biocontrol agents against sheath blight of rice caused by Rhizoctonia solani

BackgroundSheath blight of rice caused by Rhizoctonia solani is one of the most important diseases worldwide, causing considerable yield losses. The estimation of losses due to sheath blight of rice in India has been reported to be up to 54.30%. As a consequence of this fact, eco-friendly approaches were explored in this investigation.ResultsThe pathogen R. solani was isolated from the infected sheath of rice plant, which was identified and characterized on the basis of morphology and through molecular Sequencing. The sequences of ITS were submitted to NCBI GenBank and the accession number allotted is SUB11543577. In dual culture best two potential isolates of biocontrol agents were selected Pseudomonas fluorescens (Pf27) and Trichoderma harzianum (Th47). Their different combinations with Herbal Kunapajala (HKJ) were tested in glasshouse, experimental field and farmers’ fields against sheath blight pathogen R. solani. The maximum plant vigor index was found in treatment combination P. fluorescens (27) + T. harzanium (47) + Herbal Kunapajala, seed treatment, soil drenching and three foliar applications. Minimum disease severity and incidence at 30 days after sowing (DAS) and 60DAS, maximum Phenylalanine Ammonia Lyase Activity (PAL), Polyphenol Oxidase Activity (PPO) and Peroxidase Activity (PO) were also recorded in the same treatment. In field experiment the maximum population of biocontrol agents after 60 days of transplanting cfu/g soil for Trichoderma spp. (32.33 × 104) and Pseudomonas spp. (36.33 × 104) in rhizosphere and in rhizoplane. Maximum cfu/g soil for Trichoderma spp. (24.67 × 104) and Pseudomonas spp. (24.0 × 104) was observed in treatment Th + Pf + HKJ [seed treatment + soil drenching + foliar spray]. At experimental and farmers field minimum disease severity, disease incidence at 60 DAT was recorded in treatment Th + Pf + HKJ [seed treatment + soil drenching + foliar spray] and was at par with the chemical treatment Carbendazim, but the maximum yield was obtained in the treatment Th + PF + HKJ [seed treatment + soil drenching + foliar spray] due to the maximum growth promotion activity.ConclusionsAmong various treatment seed treatment, soil drenching and three foliar sprays with combination T. harzianum (47), P. fluorescens (27) and Herbal Kunapajala was found very effective in reducing the disease incidence, disease severity and increasing growth promotion activity at all conditions. Therefore, the recommendation of this investigation could be exploited under bio-intensive disease management program for sustainable cultivation of rice.

Eco-friendly management of wheat stripe rust through application of Bacillus subtilis in combination with plant defense activators

Stripe rust (SR) caused byPuccinia striiformisWestend. f. sp.triticiErikss (Pst) is one of the most important and destructive disease of wheat worldwide. In Pakistan, stipe rust appeared as epidemic and is causing huge losses to wheat production. However, wheat breeding programs are not sufficiently advanced to cope with the recently emergedPuccinia striiformisstrains. Under this scenario, current research was carried out for safe, effective and sustainable management of stripe rust of wheat. Seven wheat varieties include Sehar-06, Galaxy-13, Abdul Sattar-02, Faisalabad-08, Johar-16, TD-1 and Ujala-16 were planted at research farm of Muhammad Nawaz Shareef University of Agriculture, Multan, Pakistan during November 2019–20 and 2020–21 to determine their response toward Puccinia striiformis. The fungicide Tilt®, propiconazole, (T2) at the rate of 3 mL per 1500 mL water was used while the Bacillus subtilis (T1) was added at rate of 0.25 mL/1500 mL water with 15 g of dextrose, 0.25 g of chitosan and 0.25 g of salicylic acid in 1500 mL water to make a fine suspension. Our results showed that T1 reduced the disease effectively up to (8.18%) followed by T2 (10.7%) as compared to T0 (23.8%). The correlation between minimum air temperature, relative humidity and disease severity was highly significant while with maximum air temperature it was negatively non-significant. Also, wind speed, solar radiation and rainfall showed non-significant correlation with disease severity. After treatment, application of T1 and T2, minimum air temperature expressed a significant correlation with disease severity on varieties Sehar-2006, Galaxy-13 and Abdul Sattar-02 while non-significant correlation with disease severity on varieties Faisalabad-08, Johar-16, TD-1 and Ujala-16. Similarly, maximum air temperature, relative humidity, wind speed and solar radiation showed non-significant correlation with disease severity while rain fall was negatively non-significant. The current study showed that Bacillus subtilis is an ecofriendly management of stripe rust and its combination with plant defense activators enhance the efficacy and suppress disease. This management strategy is an innovative, and the results obtained will be helpful for better, ecofriendly and effective management of disease.

Management of spot blotch of barley through different dates of sowing and chemical and organic amendments

Spot blotch caused by Bipolaris sorokiniana is one of the most serious diseases of barley in tropical areas where barley and wheat are grown. A field experiment was conducted at Regional Research Station Masodha, ANDUA&T, Kumarganj, Ayodhya, Uttar Pradesh during Rabi season. To evaluate the effect of different dates of sowing and chemical and organic amendments on spot blotch and consequently on seed quality of barley. The experiment was conducted during the Rabi season 2016-17 under hotspot area of spot blotch. RD-2794 was sown in a split plot manner with two dates of sowing.The experiment was performed in split plot design with three replications comprising two different dates of sowing, i.e. mid- November (D1 ) and mid-December (D2 ) in the main plot and chemical and organic amendments viz., RDF (60N:30P:20K kg/ hectare) -T1 , FYM @ 5 t/h-T2 , T1 + Mulch@ 6 t/h-T3 , T1 + FYM @ 5t/hec + Mulch @ 6t/ hec.-T4 , T4 + 2 spray of zinc sulphate @ 0.5 %-T5 , T4 + 2 spray of KCl @0.5%-T6 and T5 + 2 spray of KCl @ 0.5 %-T7 in the sub plot. Results revealed that minimum disease severity (46.9%) with maximum disease control (39.98%) and per cent seed infection (5.5%) were recorded in D1 × T7 . The interpretation of data revealed that there was highly positive and significant correlation (r=0.95) between disease severity and per cent seed infection. The maximum 1000-seed weight (43.41g) and yield (38.67 q/ha) with maximum yield gain (57.25%) was also recorded in D1 × T7 . The same treatment combination was also useful in maximizing the seed quality in terms of seed viability (98%), Germination (97%), seedling length (27.30cm) and vigour index-I (2648.153) when the freshly harvested seeds were tested in seed testing laboratory. Spot blotch is a serious disease of barley spreads primarily through infected seeds and reduced the yield up to 30%. The disease can be minimized by sowing the crop timely i.e. mid-November with recommended dose of fertilizers + FYM @ 5 t/ha+ Mulch@ 6 t/ha+ 2 spray of zinc sulphate @ 0.5 % + 2 spray of KCl @ 0.5 % at flag leaf and post anthesis stage which improves the seed quality.

Prevalence of Citrus Canker caused by Xanthomonas axonopodis pv.citri. in Eastern and Northern region of Madhya Pradesh, India

Bacterial canker is one of the most common citrus diseases, causing widespread losses throughout the citrus growing regions of the world, including India. Madhya Pradesh is one among the leading states in India for citrus production. Therefore, to Keep track of the disease prevalence on lime, lemon, malta, grapefruit, and other citrus fruits, a survey was conducted in eastern (Baghelkhand) and northern (Gird) regions of Madhya Pradesh during the months of February to March 2022. Various crucial data were collected on disease severity (percentage) and disease incidence (percentage). During the survey, disease incidence was recorded from 0% to 40% range, and disease severity from 0% to 37%, with a maximum mean disease incidence (36.5%) and severity (34%), respectively, in Chinor tahsil of Gwalior district and a minimum disease incidence (18%) and severity (17.3%) in Satna district of Madhya Pradesh. Disease samples of Xanthomonas axonopodis pv.citri were collected from various villages in the chosen district during the survey (Turari, Bhanduli, Khohar, Ambha, and Panihar). After three days of purification, all five isolates showed a light yellow to yellow colour, a mucoid surface, and a circular colony with a diameter of 4 to 5.5 mm. The biochemical characteristics of bacterial isolates subjected to various biochemical tests, including the catalase test, KOH solubility test, H2 S production, and Gram reaction, were studied. All isolates were positive in catalase, KOH solubility, and H2 S production tests, but negative in Gram’s reaction. The virulence behaviour of the isolates, namely Xacl, Xac2, Xac3, Xac4, and Xac5, was diagnosed during the pathogenicity test by spraying the isolate suspension on the citrus plant. Symptoms appear 12-17 days after inoculation with a different isolate. Lesions appear on the leaf’s bottom surface as small, translucent, round spots. A yellow halo surrounded the lesions. Isolate Xac3 develops water-soaked lesions on the leaves 12 days after inoculation. Other isolates, such as Xac4, had low virulence, with symptoms showing up after16days.Xac1, Xac2, and Xac5 were all partially virulent isolates.