Bacterial stalk rot of maize caused by Dickeya zeae previously known as E. chrysanthemi pv. zeae have economic importance of reduced crop yield up to 98.8%. The disease is more prevalent in rainy season in India. The bacterium prefers high temperature and moisture for their growth result is plant toppled down within week. The pathogen has wide host range (maize, rice, tomato, chilli and brinjal etc.) which help to pathogen for long survival in soil. The bacterium characterized by biochemical and molecular tactics. In present, Pel gene and rDNA specific primers are frequently used for D. zeae characterization. The pathogen significantly controls under in vitro and in vivo condition via bleaching powder (drenching of 100 ppm) and antibiotics. The present studies generated data on pathogen nomenclature, etiology, epidemiology, host range, pathogen survival, biochemical, physiological and molecular characterization, germplasm evaluation and disease management.
Alternaria black spot of pomegranate caused by Alternaria alternata pose significant economic losses in India as it reduce the crop yield. Farm survey was undertaken at Punjab Agricultural University, Pomegranate Research Block, Fruit Research Station, Jallowal-Lesriwal Jalandhar during 2015. Among all the five cultivars highest disease incidence (70%) and severity (30%) was registered in cultivar Bhagwa. Twenty two isolates of A. alternata were recovered from infected fruits and clustered using UPGMA (unweighted pair group method with arithmetic averages) on the basis of disease score produced in five cultivars (Ganesh, Ruby, Bhagwa, Jyoti and Mridula). It was revealed that five isolates namely AL14, AL15, AL20, AL21 and AL22 were highly virulent on almost all the pomegranate cultivars. Two cultivars viz. Bhagwa and Mridula were found to be most susceptible as 45.45 % isolates were found to be highly virulent on them.The in vitro antifungal effects of the six fungicides on mycelial growth were investigated. Based on the inhibition of mycelial growth, all the fungicides showed most toxic reaction with 50% effective concentrations (EC 50 ) of < 1 ppm. However, they varied in EC90 values. 10 ppm cocentration of Tilt (azole group) showed 90% effective concentration (EC 90 ). Folicur also showed approximately same results as Tilt while EC 90 value of Natio and SAAF was <25 ppm and > 20 ppm. However, two fungicides namely Dithane Z-78 and Bavistin showed less toxicity against Alternaria alternata as compared to other with EC 90 value at concentrations <50 ppm and > 25 ppm. Azole group fungicides (Tilt and Folicur) were found most effective to inhibit the pathogen growth.
The field study was carried out at Research Farm of cotton section, Department of Genetics and Plant Breeding, CCS Haryana Agricultural University, Hisar, India to determine the effect of environmental factors and seven cotton genotypes (Bt and non Bt) on three natural enemies namely chrysoperla, coccinellids beetle and spi-ders. Natural enemies remained active throughout the crop season (with two peaks) with little differences among them. Chrysoperla and coccinellids both were remained active from 25th to 40th SMW (June to October, 2014) while spiders were active from 25th to 41st. It was observed that highest population of Chrysoperla (1.17 eggs/plant) and spiders (1.59 adult/plant) was observed on Bt cotton cultivar namely RCH-134 and JK-1947 respectively. However, coccinellids preferred non Bt genotype (HHH-223) for their population build-up. Chrysoperla and coccinellids popula-tion was significantly negatively correlated with maximum temperature (r = -0.527 at 5% and r = -0.626 at 1% re-spectively); positively correlated with RHm, RHe; negatively correlated with minimum temperature and wind speed without significance. While, spiders population showed negative correlation with all weather parameters except sun-shine hours. It was observed that population of the natural enemies fluctuated under different environmental conditions during cotton season.
Black gram (Vigna mungo L.) growing areas of district Jhansi coming under Bundelkhand region of Uttar Pradesh were surveyed during Kharif 2018 for the occurrence of anthracnose disease of black gram. A total of 22 villages were visited under six blocks of Jhansi during this period. Blockwise comparison of the survey in Jhansi revealed that less mean disease incidence (10%) and severity (4.0%) occurred in the Chirgaon block. Highest disease incidence (24%) and severity (12%) were observed in block Moth. The block Bangra, Babina, Badagaon, and Bamour secured disease incidence 23.5, 20, 16.44 and 15% and severity 15.14, 12, 7.44 and 8.5% respectively. Nine fungicides (viz. folicur@0.1%, tilt @0.1%, natio@0.0.5%, saaf@0.2%, bavistin@0.2%, dithane Z-78@0.2%, amistar top, kavach@0.2% and blitox@0.2%) were tested against anthracnose disease of black gram under field condition. Among them, seed treatment with carbendazim@ 3gram/kg seed and foliar spray of mixture of azole and strobilurin group T3- natio@0.05 ( tebuconazole + trifloxystrobin) and T7-amistar top@0.1% (azoxystrobin+ difenoconazole) were found significantly (at 0.05%) superior over the rest of treatments, both showed minimum (6%) disease severity with maximum (78.51%) disease control. Significant (at 0.05%) increase in yield (47.5%) also observed in both treatments T3 and T7. The treatment T1- Spray of Folicur@0.1%, T2- Spray of Tilt @0.1%, T4- Spray of Saaf@0.2%, T5- Spray of Bavistin@0.2%, T8- Spray of Kavach@0.2%, T9- Spray of Blitox@0.2% also showed good results in reducing the black gram anthracnose disease severity per cent (64.29, 57.14, 64.28, 57.14, 71.42 and 64.28 and also increased the yield per cent 37.5, 35, 42.5, 36.25, 45 and 45 respectively.
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