Background: Collar rot of groundnut (Arachis hypogaea L.) caused by Aspergillus niger is a significant constraint in groundnut cultivation and responsible for huge economic losses in India including Rajasthan. Methods: By surveying of eight major groundnut growing districts of Rajasthan, India, one representative Aspergillus niger isolate from each district was established (ANBK-01= Bikaner, ANCH-02= Churu, ANDA-03= Dausa, ANJP-04= Jaipur, ANJL-05= Jalore, ANJD-06= Jodhpur, ANNG-07= Nagaur and ANSK-08= Sikar) for studying variability in the pathogen as well as to know the response of groundnut varieties to the highly virulent isolate. The colony and spore characteristics were observed for cultural and morphological variability. For resistance response to the disease, ten varieties (M-13, RG-633-9, RG-382, Girnar-2, RG-604, RG-578, Gajraj 10, RG-510, RG-632-1 and RG-644) were evaluated in the field for two consecutive years against a highly virulent Aspergillus niger (ANJP-04) isolate. Result: Our investigations cleared that all the isolates were showed cultural and morphological variability such as shape, colour and size of colony and size of conidia, conidiophores and columella. Isolate (ANJP-04) collected from Khejroli village of Chomu tehsil in Jaipur district showed maximum mycelial growth, conidia diameter, length and diameter of conidiophores and length and diameter of columella, early sporulation and found most virulent as it produced higher disease incidence (54.43%). Ten released varieties of groundnut in the field conditions, revealed that none of the variety was found completely free from the disease whereas RG-644, M-13 and RG-510 were found resistant while RG-604, Girnar-2, Gajraj-10 and RG-632-1 were found moderately resistant and rest were found susceptible to highly susceptible to the disease. Conclusively, it can be finalized that famers may cultivate these resistant varieties in areas where collar rot is a severe constraint. The conclusion of this study can also be utilized to screen varieties/genotypes of groundnut against highly virulent isolate for sustainability of breeding material to the disease effectively.

Indian jujube or ber (Ziziphus mauritiana Lamk.) is one of the most common fruit, indigenous to an area joined from India to China. Powdery mildew of ber incited by Oidium erysiphoides f. sp. ziziphi, Yan and Wang is the most important disease that causes maximum reduction in yield and quality of ber fruits. Exclusive reliance on fungicides for the control of disease of various crops resulted in residue and environmental hazards. Therefore, in recent years, efforts are being diverted to employ higher plants, natural products and their derivatives as a tool for integrated disease management because they do not cause bio-accumulation, bio-magnification and environmental pollution. In present investigation, six natural products (buffalo milk, cow milk, garlic extract, neem oil, mustard oil, butter milk/chhach) were evaluated for their efficacy against powdery mildew of ber. The jujube or ber is an ancient fruit of India and China. It was one of the prominent fruits on which the sages in ancient India lived during the Vedic age and lived even today. Ber is a hardy crop which grown in arid conditions of Rajasthan, characterized by sandy soils, scanty rainfall (400-600mm), thermal oscillations (5-35 0 C) and low relative humidity. Therefore, the area of cultivation is increasing in this zone (arid and semi arid) and is expected that in near future ber will be a leading fruit crop of arid zone. The cultivation of ber requires the least input and care. In natural products maximum intensity over control was observed with garlic extract followed by neem oil, mustard oil, cow milk, buffalo milk and least effective was butter milk. Among the five systemic and non systemic fungicides (difenoconazole, dinocap, hexaconazole, tridemorph and wettable sulphur) tested against powdery mildew of ber, the maximum reduction in disease intensity over control was observed in dinocap (0.1%) with lowest per cent disease intensity (9.60) followed by hexaconazole, wettable sulphur, tridemorph and least effective was difenoconazole.

Clusterbean [Cyamopsis tetragonoloba L.) Taub.] is popularly known as "Guar" or "Guwar" and belongs to family Fabaceae of kingdom Plantae. It is an important legume crop and mainly grown under rainfed conditions of arid and semi arid regions of tropical India during Kharif and Zaid seasons. It is tolerant to drought, deep rooted and can be grown for different purposes viz., vegetable, green fodder, green manuring, production of seed and for endospermic gum (30-35 percent). Root rot caused by Rhizoctonia solani is an important and becoming severe problem of clusterbean in Rajasthan as well as India under the changing scenario of climate. This study was undertaken to find the most favorable and critical point of temperature, relative humidity and pH factors for optimum growth of the Rhizoctonia solani that may help in survival, spread and cause infection in healthy hosts. The most favorable temperature for flourishing and mycotic growth of Rhizoctonia solani was 30 0 C (90.00 mm) followed by 25 0 C (80.25 mm). Among various level of relative humidity, 90 per cent relative humidity was most favorable for maximizing growth (90.00 mm) while 6.5 pH was highly suited for maximum growth of the pathogen (632 mg dry mycelial weight). Conclusively, this pathogen requires higher temperature for fast multiplication that is prevalent in arid region of Rajasthan and due to these favorable factors this disease may be gaining importance day by day.

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Background: Root rot of clusterbean [Cyamopsis tetragonoloba (L.) Taub.] caused by Rhizoctonia solani is an important menace and causes significant economic losses in India and chemical pesticides are mostly used to overcome this problem. As per environment and health issues and demand of organic produce, the current study aimed to find the most effective control measure of this dreaded disease through eco-friendly approaches. Methods: The present field-laboratory investigations were conducted during 2018, to evaluate four bio-agents in vitro and in vivo (Trichoderma harzianum, T. viride, Bacillus subtilis and Pseudomonas fluorescens) and five organic amendments in vivo namely wool waste (@ 50 q/ ha), human hair (@ 50 q/ ha), mustard cake (@ 5 q/ ha), castor cake (@ 6 q/ ha) and neem cake (@ 5 q/ ha) were evaluated. Result: Our investigations in vitro with bio-agents depicted that T. harzianum was highly inhibitory (62.65 %) followed by T. viride (48.52%). Seed-cum-soil application (6g/kg seed + 6kg/ha) of T. harzianum was found most superior in reducing disease incidence (74.03%) followed by Trichoderma viride (69.83%) while in organic amendments, neem cake (5 q/ha) was found highly effective (70.07%) followed by castor cake (64.40%), mustard cake, wool waste and least effective was human hair. Though, wool waste and human hair least effective in disease management but preliminarily results indicated encouraging response with dual action, one in reducing disease and another in increasing plant biomass that open the future scope of further more sustainable experimentations. The findings of this study can be utilized to manage the disease effectively and eco-friendly.