Maximum Disease Control Research Articles

Assessment of Okra Powdery Mildew (Erysiphe Cichoracearum DC) by Using Bio-agents and Chemical Fungicides

The present study aimed to assess okra powdery mildew (Erysiphe Cichoracearum DC) by using bio-agents and chemical fungicides. Okra (Abelmoschus esculentus (L.) Moench occupies a prominent place in the horticultural wealth and economy of the country. Powdery mildew disease on okra (Abelmoschus esculentus (L.) Moench incited by fungus, Erysiphe cichoracearum is a limiting factor in the successful cultivation in Bundelkhand region of Uttar Pradesh. Studies were carried out to find out disease management strategies against okra powdery mildew using bioagents and chemical fungicides. Disease incidence declined after first, second and third sprays. The fungicide Hexaconazole (Contaf 5% EC) @ 0.1%, showed significantly lowest disease incidence (19.53 %) with maximum (68.40 %) disease control. On the basis of effectiveness in controlling the powdery mildew disease of okra the most effective fungicides recorded in the order of merit were Carbendazim (Bavistin 50WP) @0.1%, Propiconazole (Tilt 25EC) @0.1%, Trichoderma viride (3 %), Sulphur (Sulfex 80% WP) @ 0.3%, Pseudomonas flouresens (4 %) and Trichoderma harizum (4 %).

Effect of integration of eco-friendly components for the management of stem rot of berseem caused by Sclerotinia spp under in vivo conditions

Stem rot of berseem caused by Sclerotinia spp. is the most devastating and cosmopolitan plant disease, infecting more than 400 species of plants worldwide. The disease is reported to cause by a soil-borne plant pathogen and is responsible for significant amount of green fodder and seed yield losses in the forage crop. Integrated disease management is the practice of using a range of measures to prevent and manage diseases in crops. Total seven different combinations of eco-friendly components were integrated for their effect on the management of stem rot of berseem caused by Sclerotinia spp. under in vivo conditions. The experiment was conducted in a polyhouse using sick soil pots. Out of them, treatment T7 (TRN-10 + Eupatorium adenophorum + panchgavya + ghanjeevamrit) was found the most promising integration for the management of the stem rot disease, with terminal disease severity (13.17%) & AUDPC value (177.33) and maximum disease control (75.00%) after 35 days of inoculation. Thus it was inferred that the integration of various eco-friendly management components proved to be most effective in reducing the disease severity of stem rot of berseem.. KEYWORDS :Berseem, fodder, stem rot, Sclerotinia spp. , yield loss

In vivo Evaluation of Botanicals and Bio-Agents against Web Blight (Rhizoctonia solani) of Mungbean (Vigna radiata)

Web blight, caused by the fungus Rhizoctonia solani, poses a significant threat to mungbean (Vigna radiata) production, leading to yield losses and economic repercussions. This study investigates the antifungal of botanical extracts and bio-agents in managing web blight in mungbean crops. A series of controlled experiments were conducted to assess the antifungal properties of selected botanicals and the biocontrol potential of specific microbial agents. Various extracts, including botanicals and bio-agents have been found effective for management of web blight of mungbean caused by R. solani. The present investigation was carried out on disease management through use of botanicals and bio-agents. The minimum disease incidence and maximum disease control was obtained in Garlic followed by Ginger, Neem, Onion, Tulsi, Clerodendron, Sadabahar, at 10% concentrations at 50 days after sowing in pot sown crop, Each treatments differed significantly from each other.

Management of Charcoal Rot (Macrophomina phaseolina) of Fenugreek in Rajasthan

Background: Charcoal rot of fenugreek caused by Macrophomina phaseolina is destructive disease of all fenugreek growing areas of Rajasthan, The disease is wide occurrence in sandy soil of Rajasthan, where the climatic conditions are dry and temperature remains high. Under severe infestation it cause 35.00-42.56% losses in yield. In the present investigation, our main emphasis was to find out some new fungicides alone and combination with bio-agent for management of charcoal rot of fenugreek. Methods: Eight fungicides viz., captan 70%+ hexaconazole 5% WP, azoxystrobin 18.2% + difenaconazole 1.4% SC, chlorothalonil 75% WP, carbendazim 12% + mancozeb 63% WP, tebuconazole 50% + trifloxystrobin 25% WG, carboxin 37.5% + thiram 37.5% WP, copper oxychloride 50% WP and captan 70% WP were tested at different concentration of 100, 200, 300, 400 and 500 ppm against M. phaseolina using Poisoned Food Technique in vitro. The in vivo study was taken to evaluate the effect of one fungal and one bacterial bio-agent viz., T. harzianum, P. fluorescens was applied as seed treatment, soil dressing and soil application @ 5+5g/kg and @ 10 kg/ha respectively and fungicides viz., tebuconazole 50%+ trifloxystrobin 25% @ 1.5 g/kg, carbendazim 12% + mancozeb 63% @ 2 g/kg and azoxystrobin 18.2% + difenaconazole 11.4% 2 ml/kg seed were used in different treatments. The experiment was conducted at Experimental farm COA, SKRAU, Bikaner during Rabi 2020-21 on most popular cv. Rmt-305 in RBD design with the application of seed treatment, soil dressing and foliar spray of different fungicides with bioagents at different concentrations against Charcoal Rot disease and compared with an untreated control. Result: Among all the tested fungicides used in the present investigation, tebuconazole 50% + trifloxystrobin 25% WG found most effective in controlling the mycelium growth of pathogen. In field condition, it gave maximum disease control (85.72%) with highest grain yield (19.83 q/ha) when applied as seed treatment with tebuconazole 50% + trifloxystrobin 25% WG @ 1.5 g/kg seed + soil application of T. harzianum @ 10 kg/ha + SD with tebuconazole 50% + trifloxystrobin 25% WG. These treatments can provide an effective management of charcoal rot disease for fenugreek cultivators.

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.

INDUCTION OF SYSTEMIC RESISTANCE BY BIOTIC AND ABIOTIC COMPOUNDS AGAINST ALTERNARIA BLIGHT OF CAULIFLOWER CAUSED BY ALTERNARIA BRASSICAE

Alternaria blight of cauliflower is initiated by Alternaria brassicae, is considered as one of the significant diseases caused in cauliflower crop cultivated in all the growing areas of the world. Alternaria blight disease severity in cauliflower occurs after initiation of curd formation and continues till seed pods are set. Several opportunities include improvement of resistant cultivars; crop rotation, biological control, chemical pesticides, and tillage are used to control this particular disease. By using chemical pesticide mostly diseases can be controlled. In present investigation the three abiotic (salicylic acid, oxalic acid, benzothiadiazole and two biotic compound Trichoderma harzianum, and T.viride lab formulations were used to control this disease. Treatments were evaluated for their ability to reduce illness and prevent the production of conidia, a hallmark of pathogen proliferation. However, the disease control was maximum in variety Doctor II and under post inoculation technique. The maximum disease control was observed with the treatment of bion (93.86%) followed by salicylic Aacid (90.93%) and oxalic acid (89.06%) @ 50 mg.L concentration. The biotic compound T. harziaznum (4g/Kg seeds) also showed effective disease control (87.2%) followed by T.viride (84.53%). Although, the disease initiation in variety SV40551AC was two days later and the infection index was lower in Doctor II due to its tolerance nature. Keywords: Alternaria brassicae, cauliflower, Alternaria blight, entry routes, pathogen.

Bio-Intensive Disease Management Strategy as a Way to Control Pomegranate Wilt Caused by Ceratocystis fimbriata Ell. and Halst

Pomegranate (Punica granatum L.) is one of the important fruit crops cultivated all over the world, particularly in the tropical and sub-tropics. It is affected by several diseases of which one of the most important diseases is Ceratocystis fimbriata. In the present study, we aimed to the management of pomegranate wilt. The management, under in vitro studies, captan, mancozeb, ziram, thiram, and zineb recorded maximum inhibition of mycelial growth at all concentrations (0.10%, 0.20%, and 0.30% respectively). Out of nine systemic fungicides tested, carbendazim, hexaconazole, thiophanate methyl, propiconazole, and tebuconazole showed 100 per cent inhibition at all concentrations (0.05%, 0.10% and 0.15% respectively). In case of combi-fungicide molecules, hexaconazole + zineb, carbendazim + mancozeb, trifloxystrobin + tebuconazole and captan + hexaconazole were found highly effective. Among bio-agents tested, T. harzianum (Th-R) and Diamond (T. viride) were found more effective as compared to other bio-control agents and inhibited maximum fungal growth (100%) of C. fimbriata. The fungicides and bio-agents which showed superior performance in vitro were selected and treatment combinations were made to develop a bio-intensive integrated management strategy against pomegranate wilt under field conditions. Field evaluation over two years indicated that three drenching of propiconazole (0.2%), Diamond (T. viride) (0.7 g/l) and T. harzianum (5g/l) at an interval of 15 days showed maximum disease control.

Screening of Different Bioagents and Fungicides against Dry Root Rot of Chickpea Incited by Macrophomina phaseolina (Tassi) Goid

Background: Dry root rot of chickpea caused by Macrophomina phaseolina (Tassi) Goid is a serious biotic constraint for chickpea production in Rajasthan. For the management of soil borne disease like dry root rot of chickpea, by using fungicides alone is not feasible due to environmental and health hazards. Hence integrated management of the disease by using bio-agents and fungicides is the best alternative. Therefore, in the present investigation, our main emphasis was to identify best fungicide and bio-agent for management of dry root rot in chickpea. Methods: Eight fungicides and four bio-agents were evaluated against dry root rot pathogen (M. phaseolina) in lab as well as in field condition. The experiment was conducted at instructional farm, COA, SKRAU, Bikaner during Rabi-2019 on most popular cv. GNG-1581 in RBD design with the application of seed treatment and soil application of different bio-agents and fungicides at different concentrations against dry root rot disease and compared with an untreated control. Result: Among all the fungicides used in the present investigation, tebuconazole 50% + trifloxystrobin 25% was found most effective in inhibiting the mycelial growth of the pathogen. Among all the bio-agents, T. harzianum was found most effective in inhibiting the mycelial growth of the pathogen. Under field condition, tebuconazole 50%+ trifloxystrobin 25% WG as seed treatment @ 1.5 g/kg along with T. harzianum @ 10 kg/ha as soil application gave maximum (83.76 %) disease control with highest pod yield (19.5 q/ha) and net return (Rs 39,826/ha). These treatments can provide an effective and economical management of dry root rot disease for chickpea cultivators.

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.

Инновации в лучевой терапии при лечении рака предстательной железы: улучшение результатов и минимизация побочных эффектов

Prostate cancer is one of the most common oncological diseases affecting men and causing an increase in the mortality rate among men worldwide. Russia has also seen a significant increase in morbidity and mortality in recent years. Currently, there is no absolutely effective method of treating prostate cancer. It is necessary to search for new economically justified methods with minor side effects or without them. The purpose of this article is to compare the methods of radiation therapy, to determine the advantages of innovative methods improving results and minimizing side effects in the treatment of patients with prostate cancer. We reviewed the current state of remote radiotherapy (EBRT/DLT) in high-risk cases, including the use of androgen deprivation therapy (ADT/ADT), the role of hypofractionation and stereotactic radiotherapy (SBRT/STLT), new data on combination therapy. An analysis of publications has shown the feasibility of combining long-term ADT and remote radiotherapy in patients with high-risk prostate cancer for maximum disease control and increased overall survival compared with treatment without this combination. Randomized data suggest that increasing the dose with LDR brachytherapy may be more effective than increasing the dose with EBRT alone. Over the past decade, advances in technology, imaging capabilities, and improved radiobiological understanding have profoundly changed radiation therapy for prostate cancer, allowing for increased dose and widespread introduction of hypofractionation. In addition, the integration of magnetic resonance imaging (MRI) and improved physical accuracy of dose delivery gave impetus to additional targeting of intra-static tumor lesions previously independent of the traditional concept of determining the target of radiation therapy.

Biological management of cowpea web blight incited by Rhizoctonia solani

Among the diseases of cowpea, web blight caused by Rhizoctonia solani Kuhn is the most serious soil borne disease which causes severe yield loss. A field trial was conducted during kharif 2016 to manage web blight disease of cowpea at ARS field of SKRAU, Bikaner. Combination of T. harzianum plus B. subtilis used as seed treatment (5 + 5 g/kg) and soil application (5+5 kg/ha) proved to be most effective against web blight incited by R. solani in field conditions and provided maximum disease control (79.5%). Seed emergence, plant survival, fresh and dry weight, root and shoot lengths and grain yield was higher and per cent cowpea plant mortality was lower in treatment T. harzianum plus B. subtilis used in combination as seed treatment (5 + 5 g/kg) and soil application (5 + 5 kg/ha). The bioagents used in the present investigation could be therefore, used as a part of integrated disease management (IDM) strategy for web blight of cowpea in areas where the disease is reported to cause substantial yield losses.

Management of foot rot of citrus (Citrus jambhiri spp.) using biocontrol agents

Citrus holds an important place in promoting the horticultural wealth and economy of India. Foot rot caused by Phytophthora spp. is a widespread problem of the citrus nursery. Citrus jambhiri, a widely used rootstock in nursery production, is found susceptible to the Phytophthora spp. Hence, the present study was carried out to evaluate antagonistic activity of Trichoderma spp. isolates against Phytophthora nicotianae var. parasitica causing foot rot in C. jambhiri under lab and net-house conditions. Seven isolates (parent and mutant) of Trichoderma spp. were tested in vitro. Amongst them, T20 mutant (Trichoderma asperellum) exhibited maximum mycoparasitism, volatile activity and non-volatile activity, i.e. 83.70%, 79.26% and 84.81%, respectively. The same T20 mutant (T. Asperellum) also showed maximum glucanase activity, i.e. 1.98 unit/ml. Further, talc-based bio formulations of T. asperellum T20 isolate (parent and mutant) were tested under net-house conditions over a period of two years (2016–2017 and 2017–2018) at the research farm of Punjab Agricultural University, Ludhiana, Punjab. Amongst all the treatments, the application of T20 mutant (T. asperellum) (seed + soil 15 g) had minimum disease incidence (13.33%), maximum disease control (83.30%) and maximum growth promotion i.e. shoot length (37.67 cm) and root length (30.67 cm). Based on our findings, T. asperellum T20 mutant strain used as seed + soil treatment was able to effectively manage the foot rot, in C. jambhiri nursery under net-house conditions and also promoted the plant growth.

Biocontrol of Fruit Rot of Litchi chinensis Using Zinc Oxide Nanoparticles Synthesized in Azadirachta indica.

Lychee (Litchi chinensis Sonn.) is a famous fruit species of tropical and subtropical regions of the world and many biotic and abiotic stresses affect its yield. In this study, lychee fruit rot has been observed and its incidence has been controlled by using zinc oxide nanoparticles (ZnO NPs). Diseased lychee fruits were collected and diagnosed to identify disease-causing pathogens. Morphological appearance, microscopic observation, and sequence analysis of the amplified ITS region identified this isolated pathogen as Aspergillus niger. To control this problem, ZnO NPs were prepared in the leaf extract of Azadirachta indica. Before their antifungal activity, ZnO NPs were characterized using sophisticated approaches. FTIR revealed the presence of reducing and stabilizing molecules on ZnO NPs including alcohol, carboxylic acid, alkyl halide, amine, and alkyl halide. Crystalline nature and average size (29.024 nm) of synthesized ZnO NPs were described by X-ray diffraction. EDX analysis depicted the mass percentage of zinc (30.15%) and oxygen (14.90%). SEM analysis displayed the irregular shape of nanoparticles and confirmed the nano-size of ZnO NPs. Maximum mycelial growth inhibition (70.5%) was observed at 1.0 mg/mL concentration of ZnO NPs in vitro. In in-vivo disease-control analysis, maximum control of lychee fruit rot disease was observed at the same concentration. These results reveal the potential use of these ZnO NPs on a larger scale to replace hazardous chemical fungicides.

Evaluation of newer fungicides against neck blast disease of rice under field condition in south-eastern Rajasthan

Neck blast is considered as the most destructive phase of the blast disease in rice under south-eastern Rajasthan. Eight new generation fungicides viz., Tebuconazole, Difenconazole Propiconazole , Hexaconazole Azoxystrobin , Azoxystrobin +Tebuconazole ,Azoxystrobin Mancozeb Trifloxystrobin +Tebuconazole were evaluated under field conditions during Kharif 2021. Result revealed that the combination of Trifloxystrobin (25%) + Tebuconazole (50 WG @ 0.4g/lit) gave minimum disease intensity (3.2%) and maximum disease control (80.8%) with higher yield (4482.3 kg/ha) which was at par with Propiconazole with a grain yield of 4400.0 kg/ha.

Evaluation of Novel Fungicide for the Management of Soybean Anthracnose Disease and Yield Loss Estimation

Background: Soybean anthracnose is currently a severe threat to India’s soybean cultivation. There is limited information about estimated yield loss due to anthracnose and foliar fungicide application for its management. Methods: A novel fungicide, Picoxystrobin 7.05 per cent + Propiconazole 11.71 per cent (w/w) was evaluated for two consecutive years (2018 and 2019) in three different concentrations as a foliar application in combination with commercially available fungicides as standard checks to identify an alternative fungicide for management of soybean anthracnose disease. The yield loss was estimated from the data observed for two years in a row. Result: After three foliar applications of the novel fungicide, Picoxystrobin 7.05 per cent + Propiconazole 11.71 per cent w/w @ 0.20 per cent, the maximum disease control (PDC), the lowest disease index (PDI) and the area under the disease progress curve (AUDPC) were obtained. The maximum gross return was obtained following three foliar applications of Picoxystrobin 22.52 per cent (w/w) SC @ 0.08 per cent, but the maximum B:C ratio was estimated with foliar application of Hexaconazole 5.00 per cent EC @ 0.100 per cent. Anthracnose severity was found to be negatively correlated with soybean grain yield (r = -0.91). In every 1% increase in anthracnose disease severity reduced soybean yield by 115 kg per hectare.

Management of Green Mold Disease in White Button Mushroom (Agaricus bisporus) and Its Yield Improvement.

Mycoparasites cause serious losses in profitable mushroom farms worldwide. The negative impact of green mold (Trichoderma harzianum) reduces cropping surface and damages basidiomes, limiting production and harvest quality. The goal of the current study was to evaluate new generation fungicides, to devise suitable management strategies against the green mold disease under prevailing agro-climatic conditions. Six non-systemic and five systemic fungitoxicants were evaluated for their efficacy against pathogen, T. harzianum, and host, Agaricus bisporus, under in vitro conditions. Among non-systemic fungicides, chlorothalonil and prochloraz manganese with mean mycelium inhibition of 76.87 and 93.40 percent, respectively, were highly inhibitory against the pathogen. The least inhibition percentage of 7.16 of A. bisporus was exhibited by chlorothalonil. Under in vivo conditions, use of captan 50 WP resulted in a maximum yield of button mushroom of 14.96 kg/qt. So far, systemic fungicides were concerned, carbendazim proved extremely inhibitory to the pathogen (89.22%), with least inhibitory effect on host mycelium (1.56%). However, application of non-systemic fungitoxicants further revealed that fungicide prochloraz manganese 50 WP at 0.1–0.2 percent or chlorothalonil 50 WP at 0.2 percent, exhibited maximum disease control of 89.06–96.30 percent. Moreover, the results of systemic fungitoxicants showed that carbendazim 50 WP or thiophanate methyl 70 WP at 0.1 percent reduced disease to 2.29–3.69 percent, hence exhibiting the disease control of 80.11–87.66 percent. Under in vivo conditions, fungicide myclobutanil at 0.1 percent concentration produced the maximum button mushroom production of 12.87 kg/q.

Integrated Management of Root Rot Disease Complex of Tomato (Solanum lycopersicum L.) Incited by Concomitant Occurrence of Rhizoctonia solani and Meloidogyne javanica

Tomato (S. lycopersicum L.) is an important vegetable crop not only for its economic importance but also because of its nutritional value. The root rot disease complex of tomato is considered as a common problem in tomato fields of Haryana due to concomitant occurrence of R. solani and M. javanica. It is very difficult to manage the disease complex through fungicides and nematicides alone which despite of being costly are not eco-friendly as well. Therefore, in this study, an attempt was made to explore and exploit other methods of root rot disease complex management in an integrated manner. The different treatments like organic amendment (mustard cake), fungicide (Carbendazim 50 % WP), mycorrhizal fungi (Glomus mosseae) and biocontrol agent (Trichoderma harzianum) were evaluated in different combinations for the integrated management of root rot disease complex in tomato cv. Hisar Arun (Selection 7). The evaluation of different treatments and their combinations under in vivo condition revealed that a significantly low disease incidence (10.5 per cent) and a maximum disease control of 83.4 per cent was observed when seeds were dressed with Carbendazim 50 % WP @ 2g/kg seed and sown in soils incorporated with T. harzianum (10g/kg soil), G. mosseae (200 sporocarps/kg soil) and mustard cake (2g/kg soil). It was followed by disease incidence of 13.7 per cent when Carbendazim dressed seeds (2g/kg seed) were sown in soil incorporated with T. harzianum (10g/kg soil) and mustard cake (2g/kg soil). It is possible to manage the disease complex only by the use of integration of different treatments including seed dressing with carbendazim, soil incorporation of T. harzianum, G. mosseae and soil amendments with mustard cake which acted in a synergistic way.

​Management of Early Leaf Spot (Cercospora arachidicola) of Groundnut in Rajasthan

Background: Early leaf spot caused by Cercospora arachidicola Hori. is most destructive disease in all the groundnut growing areas of Rajasthan, under severe infestation it cause 30-50% losses in pod yield. Recently, Central Insecticide Board (CIB), Faridabade banned 27 pesticides including some important fungicides which are extensively used in plant disease management. Therefore, in the present investigation, our main emphasis was to find out some new fungicides for management of early leaf spot disease. Methods: Ten fungicides (hexaconazole 5% EC, difenconazole 25% EC, propiconazole 25% EC, tebuconazole 25.9% EC, trifloxystrobin 25% + tebuconazole 50% WG, mancozeb 50% WP, chlorothalonil 75% WP, carbendazim 50% WP, carbendazim 12% + mancozeb 63% WP and captan 70% + hexaconazole 5% WP) were evaluated against early leaf spot pathogen (C. arachidicola) both in lab as well as in field condition. The experiment was conducted at ARS, SKRAU, Bikaner during Kharif-2019 on most popular cv. HNG-69 in RBD design with the application of foliar spray of ten different fungicides at different concentrations against early leaf spot disease and compared with an untreated control. Result: Among all the fungicides used in the present investigation, Tebuconazole 25.9% EC was found most effective in inhibiting the mycelial growth of the pathogen followed by trifloxystrobin 25% + tebuconazole 50% WG. Under field condition, it gave maximum (70.73%) disease control with highest pod yield (31.5 q/ha) and net return (Rs 57,500/ha) when applied as foliar spray at 0.1% concentration followed by trifloxystrobin 25% + tebuconazole 50% WG at 0.2%. These treatments can provide an effective and economical management of early leaf spot disease for groundnut cultivators.

English

Leaf rust disease affects the wheat crop in several countries around the globe and it can influence the grain yield and its components. This research was carried out using 35 wheat genotypes during the growing season of 2016-2017 with 3 replications by RCBD under contrasting rust disease regimes. The statistical techniques used for the multivariate analyses include the calculations of correlations, principal components and clusters. The data about various physiological traits, grain yield components and disease severity were recorded under high disease pressure and maximum disease control conditions. Correlation analysis showed highly significant positive relationship of disease severity with relative membrane permeability but negative association with chlorophyll contents in the flag leaf and some yield attributes. In control conditions, the relative water content exhibited a highly significant positive relationship with the flag leaf area while highly significant negative relationship was observed with specific flag leaf weigh under disease condition. Principal component analysis demonstrated that first 4 PCs having eigenvalue >1 elucidated 73.578% and 82.80% of the total variation under diseased and control conditions respectively. Cluster analysis grouped 35 wheat genotypes among four different clusters. The members of cluster 1 revealed the maximum disease severity under control condition, but the disease severity was maximum for cluster 4 under disease condition. Scatter plot explained that, not a single cluster showed clear separation. The tree diagram also indicated that diversity in different disease conditions is controlled by genotypes. The results concluded that this genetic diversity could be helpful to the researchers and breeders for future objectives to enhance the food production and leaf resistance in bread wheat. Keywords: Wheat, Leaf rust, Multivariate analysis, Genetic diversity, Morpho-physiological traits

Non-chemical strategies in integrated management of wilt and stem rot diseases of chrysanthemum

Wilt and stem rot caused by Fusarium oxysporum f sp. chyrsanthemi and Rhizoctonia solani are most devastating diseases, amounting to cause 18 -27 per cent loss under congenial environmental conditions in chrysanthemum. Due to many issues such as fungicide resistance, cost, and adverse effects, eco-friendly integrated approaches seem to be an applicable management method against the wilt and stem rot diseases of chrysanthemum. The objective of our present study was to evaluate the alternative methods such as soil amendments, biological agents and soil solarization (SS) alone and in integrated form which are cheap and easily adoptable having long-term benefits in combating the wilt and stem rot infection of chrysanthemum. Neem cake and cotton cake were found superior against Fusarium wilt pathogen with highest 68.11 per cent disease reduction while mustard cake showed highest effectiveness followed by neem and groundnut cakes to minimize the Rhizoctonia solani infection by 64.29 per cent. Fungal antagonists proved better in controlling disease compared to bacterial antagonist. For soil solarization, 25µ thickness polythene sheet resulted in less disease than 50 µ thickness. Integration of all the components resulted into excellent control of stem rot and wilt under field conditions due to additive effects. Maximum disease control (73.15 %) achieved in SS+ T. harzianum + Neem cake, SS+ T. harzianum + T. viride. A drastic decrease in the inoculums load of both pathogens recorded after two months period in solarized than unsolarized soils with varied microbial counts and almost negligible appearance of weeds in solarised plots.