![]() The bacterium is also seed-borne and remains in the form of slimy mass on the fuzz of seed coat. The bacterium survives on infected, dried plant debris in soil for several years. Rain followed by bright sunshine during the months of October and November are highly favorable.Relative humidity of 85 per cent, early sowing,.High atmospheric temperature of 30-40˚C,.It is Gram negative, non-spore forming and measures 1.0-1.2 X 0.7-0.9 µm. ![]() The bacterium is a short rod with a single polar flagellum. The pathogen also infects the seed and causes reduction in size and viability of the seeds.īacterial blight lesions on leaf and the blackleg symptom on the leaf petiole The bacterium spreads inside the boll and lint gets stained yellow because of bacterial ooze and looses its appearance and market value. The infection on mature bolls lead to premature bursting. The infection slowly spreads to entire boll and shedding occurs. On the bolls, water soaked lesions appear and turn into dark black and sunken irregular spots. On the stem and fruiting branches, dark brown to black lesions are formed, which may girdle the stem and branches to cause premature drooping off of the leaves, cracking of stem and gummosis, resulting in breaking of the stem and hang typically as dry black twig to give a characteristic “black arm” symptom. The infection also spreads from veins to petiole and cause blighting leading to defoliation. The affected leaves become crinkled and twisted inward and show withering. On the lower surface of the leaf, bacterial oozes are formed as crusts or scales. The infection of veins cause blackening of the veins and veinlets, gives a typical ‘blighting’ appearance. Iii) Vein blight or vein necrosis or black vein: As the lesions become older, they turn to reddish brown colour and infection spreads to veins and veinlets. ![]() Small, dark green, water soaked areas develop on lower surface of leaves, enlarge gradually and become angular when restricted by veins and veinlets and spots are visible on both the surface of leaves. ![]() Small, water-soaked, circular or irregular lesions develop on the cotyledons, later, the infection spreads to stem through petiole and cause withering and death of seedlings. Usually five common phases of symptoms are noticed. The bacterium attacks all stages from seed to harvest. hamatum was noticed to the tune of 50.94, 48.03 and 44.12 per cent, respectively.COTTON :: MAJOR DISEASE :: BACTERIAL BLIGHTīacterial blight - Xanthomonas axonopodis pv. Per cent reduction in colony diameter (mm) of the pathogen after 3, 6 and 9 days of incubation in T. malvacearum, Trichoderma hamatum was significantly superior in per cent reduction of mycelia colony diameter (mm) of pathogen at all the incubation periods tested. Amongst the antagonist tested against Xanthomonas axonopodis pv. copper oxychloride 0.25 % + streptocycline 100 ppm sprays to the tune of 11.83 per cent (PDI) and 19.36 per cent (PI) respectively as against the unsprayed control 27.56 per cent and 45.51 per cent respectively and obtained significantly higher seed cotton yield 2567.33 kg/ha followed by carbendazim 0.1 % + streptocycline 100 ppm. Significantly low disease severity and low disease incidence were recorded in treatment T4 i.e. malvacearum | Gossypium spp | Chemicals | Bioagents ABSTRACT An experiment was carried out to see the efficacy of different chemicals and bioagents against bacterial blight disease severity (PDI) and disease incidence (PI). Dey Journal: Scientific Journal of Microbiology ISSN 2322-2948 Volume: 1 Issue: 1 Start page: 10 Date: 2012 Original page Keywords: Management | Xanthomonas axonopodis pv.
0 Comments
Leave a Reply. |
Details
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |