{'fraction_non_alphanumeric': 0.029765842042598228, 'fraction_numerical': 0.017462627331657626, 'mean_word_length': 4.901639344262295, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Screening of fungicides and bio-control agents against Sclerotium rolfsii (Sacc.) causing collar rot in Lentil

Lentil is an important pulse crop, contributes about 8-9% of the total pulse production in India and is also a major source of protein, minerals and vitamins. Collar rot of lentil is an important seedling disease caused by Sclerotium rolfsii Sacc. In this study, twenty isolates (Th1-Th20) of Trichoderma harzianum, one isolate of Pseudomonas fluorescence and nine commercially available fungicides were tested in vitro for their efficacy in inhibiting the growth of the pathogen. Trichoderma harzianum isolate Th16 and Th14 were found to inhibit maximum mycelial growth of the pathogen. The complete inhibition of mycelial growth of Sclerotium rolfsii was found with Propiconazole, Tabuconazole, Hexaconazole, Ridomil and Carbendazim+ Mancozeb at all (0.03%, 0.05% and 0.1%) concentrations. Other fungicides (Captan, Mancozeb and Carbendazim) also showed significant inhibition of the mycelial growth of the pathogen. No inhibition was recorded in the treatment with copper oxychloride even at 0.2% concentration.


Introduction
Lentil, (Lens culineris) is a bushy, annual shrub plant that is popular for its lens shaped seeds and nutritious value of the seeds that is rich in protein, fibers having second highest levels of proteins and fiber after soybeans. The tap root system of the plant usually grows to a depth of around 15 cm that makes it a moderately drought resistant crop. India is second top producer of lentil in the world after Canada. In India, total area covered by lentil producers is about ~1.3 million hectares (APEDA, 2015) [1] . World lentil production has been increasing in recent years with most of the production coming from North American and Asian countries. Productivity of lentil in India varies from region to region due to variation in environment and biotic factors. Lentil is attacked by fungal, viral and bacterial pathogens. Sclerotium rolfsii is one of the important soil borne fungal pathogens having a wide host range and world-wide distribution (Punja, 1988) [8] , causing collar rot, root rot, stem rot and wilt on more than 500 plant species including almost all the agricultural and horticultural crops. The fungus is a soil borne pathogen of very aggressive nature and causes considerable damage to young seedlings causing collar rot resulting in substantial yield losses. S. rolfsii produces sclerotia which is the principal structure to survive under adverse conditions. Control of soil borne pathogens has become one of the major concerns in agriculture. However effective and efficient management of crop diseases is generally achieved by the use of synthetic pesticides. These pesticides are known to pollute the environment, soil and water, besides causing deleterious effects on human health and biosphere. The present investigation is related to the study of the management of collar rot disease of Lentil by different fungicides and bioagents and comparing the efficacy of both.

Material and Methods Experimental site, Location and Collection of diseased specimens-
The experiments were conducted at Department of Plant Pathology, Sardar Vallabhbhai Patel University of agriculture and Technology, Meerut (Uttar Pradesh).
Isolation and identification of pathogen-Infected lentil plants showing the typical symptoms of collar rot collected from Crop Research Centre (CRC) of Sardar Vallabhbhai Patel University of Agriculture and Technology, Meerut and from farmers' field in the vicinity of Meerut. All specimens were collected and placed in a moist chamber at 25ºC. Besides this the collar portion of the infected plants were cut in 3-5 mm thick tissue sections and sterilized with 0.1% sodium hypochlorite solution for 30 seconds, rinsed thrice in sterilized distilled water (SDW) and dried on sterilized filter paper at room temperature. The tissue sections were then placed on potato dextrose agar (PDA) amended with 100 µg/ml streptomycin sulphate and incubated at 25 o C for fifteen days. The pure culture of the pathogen was isolated and subsequently maintained on PDA.
Isolation of biocontrol agent-Soil samples were collected from the rhizospheric region of healthy plants from different locations of Meerut district for isolation of biocontrol agents. By using dilution plate techniques, Bio control agents were isolated, purified and identified on the basis of their morphological characters (Nashwa et al, 2008; Rifai, 1969) [6,9] The obtained Bioagents (Fungi-Trichoderma Spp.) were maintained in PDA and (Bacterial-P. fluorescens) maintained in King's B agar slants.

In vitro evaluation of bio-agents against S. rolfsii
The tested isolates of Trichoderma spp. were grown on PDA medium at 20°C, for 6-days and used as inocula. Culture discs from each isolate of Trichoderma spp. and the pathogen (S. rolfsii) were inoculated opposite to each other at 4cm apart in the petriplate containing 20 ml PDA and the antagonistic properties of the test bioagents were exhibited (dual culture technique). Five replicates were used for each isolate of Trichoderma spp.. The inoculated plates with culture discs of pathogen without bioagents served as control. After 24, 48, 72 and 96 hrs of incubation at 20°C, radial growth of pathogen and percent inhibition was recorded. Inhibition percent of pathogen growth was calculated using the following formula:

I = − 100
Where, I = Per cent inhibition C = Growth in control T= Treatment

In vitro evaluation of fungicides against S. rolfsii
Effect of eight fungicides belonging to different groups (listed in Table-2) with different concentrations (viz., 0.03, 0.05 and 0.1 per cent for systematic fungicide and 0.05, 0.1 and 0.2 per cent for non-systemic fungicides) were tested in vitro for evaluating their efficacy to inhibit the growth of the pathogen. Effect on the growth of S. rolfsii was studied using poisoned food technique (Nene and Thapliyal, 1982) [7] . 20 ml of poisoned medium was poured into each of the 90 mm sterilized petriplates. Each plate was inoculated with five mm disc of mycelium at the center and incubated at 27± 1 0 C. Three replications were maintained for each treatment. Potato dextrose agar medium without any fungicide served as control. All plates were incubated at 27± 1 0 C till the growth completed in control plate. The per cent inhibition of the growth over control was calculated by following the equation given by Vincent (1927).
Where, I = Per cent inhibition C = Growth in control T = Growth in treatment

Results
Isolation and identification of pathogen: On PDA plates, the fungus produced silky, white mycelium, which gradually losses its luster and became somewhat dull in appearance. Aerial hyphae grow fast, were not uniformly distributed. The hyphae were septet, hyaline, clamp connections occurred in the broader threads and branching was at right angles behind the cross wall. The individual hyphal cells were 60-350 µm in length and 2-8 µm in diameter.
After the mycelial mat develops, the sclerotial initials formed from hyphal strands lying parallel. A spherical shape was assumed by the loose mass of hyphae. The fully matured sclerotia were spherical, light to dark brown in colour, embedded in fuzzy mycelial mat and measured 1.5 to 4.2 mm in diameter. Initiation of sclerotial bodies was observed from fifth day onwards after inoculation. Sclerotia may be seen in the mycelium, on diseased tissues above or below ground, on soil surfaces, or in soil crevices also (West, 1961) [11] .