Bacterial leaf blight incited by Pseudomonas cannabina pv. alisalensis (Pca) is a devastating dis... more Bacterial leaf blight incited by Pseudomonas cannabina pv. alisalensis (Pca) is a devastating disease with incidence reports worldwide and a wide host range capable of infecting all commercially valuable Brassica crops. With no chemical control options available, the most effective form of disease control is host plant resistance, but thus far resistant germplasm has only been identified in Brassica juncea L. (mustard greens). We report the first screening of Brassica oleracea L. var. viridis germplasm, including leafy green collard and collard-like accessions, for resistance to bacterial leaf blight by artificial inoculation of Pca in greenhouse trials. All commercial cultivars tested displayed an intermediate disease response resulting in leaf lesion development that renders the product unmarketable. Two sources of significant resistance were identified in the U.S. Department of Agriculture (USDA) viridis collection, which provides a valuable source of resistance alleles for colla...
Control of bacterial leaf spot of mulberry caused by Xanthomonas campestris pv. mori
Indian Journal of Sericulture, 2000
In order to develop biological control of bacterial leaf spot (BLS) of mulbeny caused by Xanthomo... more In order to develop biological control of bacterial leaf spot (BLS) of mulbeny caused by Xanthomonas campestris pv. mori, mulbeny phylloplane-fungi and bacteria were isolated and screened in vitro. Phylloplane fungi, viz., Aspergillus Ochraceus, A Bavus, A. niger, Curvularia lunata, Cladosporium oxysporum, Fusarium pallidoroseum, Paecilomyces varioti, Nigrospora orizae, did not exhibit antibiosis against X campestris pv. mori. Phylloplane bacterial strains, viz., Bacilhus sp., Micrococcus spp., exhibited antibiosis against X compestris pv. mari in vitro. Phylloplane bacteria were tested for efficacy in potted mulbeny plants against BLS. Two sprays of Bacillus sp. at 0.1 (00) at 10 dyas interval reduced bacterial leaf spot severity, which at par with Plantomycin and Pushamycin.
Aizawl as a rainfed area is located at 1132 meter above sea level (MSL). Total area of mulberry o... more Aizawl as a rainfed area is located at 1132 meter above sea level (MSL). Total area of mulberry of Mizoram is 5100 hactere which caters 5593 sericulture families (mulberry) of the state, where mulberry varieties {SI and S 1635) are cultivated as bush or as dwarf tree forms. Among the diseases of this locality powdery mildew {Phyllaetinia eorylea), myrothecium leaf spot {Myrotheeium roridum) and leaf rust (Perdiopsora mori) are very common. Feeding of diseased leaves results poor cocoon crop and consequently reduction in the income of the rearers. Therefore timely management for control of disease and pests is prerequisite for harvesting healthy and nutritious leaves. Disease not only reduces leaf yield but also causes degradation in the quality {Quadri et al., 999) and feeding of diseases leaves results prolonging of larval period (Noamani et al., 1970 and Kumar et al., 1993). The study was carried in the three villages of Aizawl districts viz., Khamrang, Dilkhan, and Seling. Occurr...
Screening of mulberry genotypes for disease resistance in different seasons to bacterial leaf spot
Indian Journal of Genetics and Plant Breeding, 2009
Eighty two mulberry germplasm accessions were evaluated for stable resistance to Bacterial leaf s... more Eighty two mulberry germplasm accessions were evaluated for stable resistance to Bacterial leaf spot (BLS) pathogen Xanthomonas campestris pv. mori in field condition. Disease reaction was scored by 0–5 scale at 60 days after pruning. Germplasm with low disease severity, regression coefficient nearer to one and regression deviations variance nearer to zero were considered highly stable. Accordingly, Morus rotundiloba and MS-8 were observed to be stable accessions. Besides, these two accessions represented as unique entries in clustering of genotypes and showed maximum divergence. Therefore, M.rotundiloba and MS-8 may be considered as useful sources of stable resistance to bacterial leaf spot for utilization in mulberry improvement programme. The genotype Surat with maximum disease severity, regression coefficient nearer to one and regression deviations variance nearer to zero may be exploited as susceptible source in BLS resistance breeding programme.
Evaluation of some Ethanobotanical Plant Extracts for Fungitoxicity against Myrothecium roridum
Ethanolic extracts of twenty-one plant species were tested in vitro for their fungitoxic properti... more Ethanolic extracts of twenty-one plant species were tested in vitro for their fungitoxic properties against leaf spot causing pathogen of mulberry Myrothecium roridum by poisoned food technique. Ethanolic extracts of twenty-plant spp. reduced mycelial growth of M. roridum significantly except E. pulcherrima. Highest inhibition of M. roridum colony growth observed in 10% extracts of E. citriodora (49.45%) followed by D. mete! (39.45%), Chromo!aena odoratum (25.56%) and A. sativum (25.00%). Among the concentration tested, 10% concentration was found significantly higher effective on reducing colony growth followed by 5 and 2.5%. Aqueous extract fresh leaves/bulb of seven short-listed plant spp. (inhibition >15% in ethanolic extracts) revealed that D. metel inhibited (23.43%) followed by E. citriodora (14.66%), C. odoratum (13.53%). On dry leaf extracts D. metel was found more effective than E. citriodora. The results indicated that D. metel, E. citriodora, C. odoratum and A. sativu...
silkworm (Bombyx mori) is prone to several foliar diseases caused by fungi, bacteria, virus and m... more silkworm (Bombyx mori) is prone to several foliar diseases caused by fungi, bacteria, virus and mycoplasma. Among them, powdery mildew (Phyllactinia corylea), leaf rust (Peridiopsora mori), Pseudocercospora leaf spot (Pseudocercospora mori), Myrothecium leaf spot (Myrothecium roridum) and sooty mold (Ascomycetes and Deutoromycetes fungi) are major foliar diseases of mulberry in the eastern and north eastern India (7,8). About 10-15% leaf yield loss occurs due to powdery mildew, leaf rust and leaf spot diseases (3,9). Besides, these diseases also reduce leaf quality drastically leading to poor silkworm rearing. Qadri et al. (11, 12) reported crop loss up to 54.56% and 55.59% at maximum disease severity of leaf spot and powdery mildew, respectively.
Bacterial leaf spot (BLS) caused by pv. was found to be one of the major foliar diseases in mulbe... more Bacterial leaf spot (BLS) caused by pv. was found to be one of the major foliar diseases in mulberry at farmers field in Birbhum district. BLS incidence appeared in May and continued up to November. The correlation coefficient between disease severity and meteorological parameters revealed that BLS disease severity showed significant positive correlation with max & min temperatures, min relative humidity, rainfall and number of rainy days. Step down multiple regression analysis revealed that the forecasting of BLS could best be done from min temp, minimum relative humidity and number of rainy days. Xanthomonas campestris mori
Evaluation of mulberry phylloplane bacteria for biocontrol of Myrothecium leaf spot of mulberry caused by Myrothecium roridum
Agricultural science digest, 2004
In order to develop biological control of Myrothecium leaf spot (MLS) of mulberry caused by Myrot... more In order to develop biological control of Myrothecium leaf spot (MLS) of mulberry caused by Myrothecium roridum , mulberry phylloplane bacteria were isolated and screened in vitro against the pathogen. Out of six-phylloplane bacterial strains three phylloplane bacterial strains exhibited antibiosis against M. roridum in vitro . Field efficacies of six phylloplane bacterial strains were tested in potted mulberry plants against MLS under inoculated condition. Twenty four hour old bacterial suspension (l0 8 CFU/ml) of two Bacillus spp, three Micrococcus spp. and one Serratia sp. was sprayed 24 hr prior to inoculation of M. roridum conidial suspension (10 6 CFU/ml). All six phylloplane bacterial strains reduced MLS disease severity more than 44.5% even 30 days after inoculation.
Genetic variability in mulberry against Myrothecium leaf spot (Myrothecium roridum) and identification of resistance genotypes
Archives of Phytopathology and Plant Protection, 2011
... A new leaf spot disease of mulberry caused by Myrothecium roridum Tode Ex Fr. Curr Sci, 58: 3... more ... A new leaf spot disease of mulberry caused by Myrothecium roridum Tode Ex Fr. Curr Sci, 58: 398 [Web of Science ®], [CSA]; 4. Jindal, PC and Bhavani, S. 2002. ... 2000. Control of bacterial leaf spot of mulberry caused by Xanthomonas campestris pv. mori. ...
During monsoon and post-monsoon season (July to October), a new brown ring leaf spot disease was ... more During monsoon and post-monsoon season (July to October), a new brown ring leaf spot disease was observed in the mulberry Germplasm Bank at Berhampore, West Bengal. The disease first appeared in the form of small, brown, irregular spots, which later coalesced and formed bigger spots, arranged in nearly concentric rings. The old spots were visible on both the surfaces of leaves. The vein portion of leaves remained green and intact. The infected leaf tissue withered and cracked. On the ventral surface of spots, mycelium was present in the form of hyaline, sterile, creeping hyphae with short branched conidiophores and conidia. The pathogen was isolated in potato dextrose agar medium. Pathogenicity test was conducted and established in accordance with Koch's postulates using approximately two months old saplings of Italian mulberry variety 'Cattaneo'. Typical disease symptoms appeared within 10 days after inoculation and the same pathogen was re-isolated from inoculated leaves. On potato dextrose agar, colonies were floccose, white at first which later turned into rose colour. Conidiophores, branched, aseptate; conidia, hyaline, elliptical, 8-10 11mx 3.5-4.0 11m.The fungus was identified by Indian Agricultural Research Institute, New Delhi as Cephalosporium strictum (ITCC/2994/97).
Development of leaf rust (Peridiopsora mori) and dispersal of urediniospores in mulberry (Morusspp.)
International Journal of Pest Management, 2000
Studies were conducted on the effect of pruning time, host age, urediniospore release and weather... more Studies were conducted on the effect of pruning time, host age, urediniospore release and weather parameters on the incidence and intensity of mulberry leaf rust (Peridiopsora mori). Rust severity significantly increased with increasing shoot age, irrespective of pruning ...
Archives Of Phytopathology And Plant Protection, 2012
In order to develop weather-based forecasting model of bacterial leaf spot (BLS) disease of mulbe... more In order to develop weather-based forecasting model of bacterial leaf spot (BLS) disease of mulberry caused by Xanthomonas campestris pv. mori, weekly disease severity data were recorded for three years on the ruling cultivar S-1. Daily meteorological data viz. maximum temperature, minimum temperature, maximum relative humidity, minimum relative humidity, rainfall and number of rainy days were also recorded. It was observed that BLS appeared in April/May and continued up to November with maximum severity in July. The correlation coefficient between disease severity and meteorological parameters revealed that the BLS disease severity has significant positive correlation with minimum temperatures, maximum and minimum relative humidity, rainfall and number of rainy days and negative correlation with maximum temperature. Multiple regressions analysis revealed that average of maximum temperature, minimum temperature and rainfall of preceding seven days and maximum relative humidity, minimum relative humidity of previous 9-15 days was found to maximally influence BLS disease severity. The contribution of the meteorological factors was found to be highest of minimum temperature (40.65%) followed by maximum temperature (24.20%), maximum relative humidity (16.41%), minimum relative humidity (8.07%), rainfall (5.29%) and number of rainy days (5.38%).
Archives Of Phytopathology And Plant Protection, 2011
The disease response and magnitude of genetic variability of 85 mulberry genotypes of different a... more The disease response and magnitude of genetic variability of 85 mulberry genotypes of different agroclimatic origin was studied against powdery mildew caused by Phyllactinia corylea. It was observed that there was a wide variation of disease severity among the test genotypes. Australian and France originating genotypes were found to be highly resistant to mildew followed by of Thai and Italian origin. Genotype wise, the lowest mildew disease severity was recorded in Thailand [lobed]) followed by M. malticaulis, M. australis and Italian. Genetic analysis of disease severity revealed that the estimate of phenotypic coefficient of variation (PCV) and genotypic coefficient of variation (GCV) were high and that PCV was greater than GCV. High estimate of heritability coupled with high genetic advance showed that the mildew disease resistant trait is governed by an additive gene action. Hence the highly resistant mulberry genotypes identified may be exploited through hybridisation followed by selection under epiphytotic conditions for the improvement of disease resistant traits in mulberry.
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