Survival of helminthosporium leaf blight pathogens of wheat in seeds, soil and other weed hosts under wheat based cropping systems in Rampur, Chitwan, Nepal.

Neupane, A. C., S. M. Shrestha, G. B. KC and N. K. Chaudhary. 2007. IAAS Research Advances Vol. 1. Institute of Agriculture and Animal Sciences, Rampur, Chitwan, Nepal. pp. 163-169.

Keywords: Bipolaris sorokiniana, Drechslera tritici-repentis, Triticum aestivum, HLB complex

Helminthosporium leaf blight (HLB), a complex of spot blotch caused by Cochliobolus sativus and tan spot caused by Pyrenophora tritici-repentis, is a major biotic constraint of wheat production in the Eastern Gangetic plains of South Asia, particularly in areas where rice-wheat cropping system is practiced. To have a better understanding of the disease epidemics, present study was focused to determine the survival of B. sorokiniana and P. tritici-repentis in seeds, soil and other host plants under wheat-rice-wheat (W-R-W), wheat-green manure-wheat (W-G-W) and wheat-fallow-wheat (W-F-W) cropping systems. Seed infection with B. sorokiniana was found the highest in BL 1473 (95%) followed by Sonalika (93%) and Milan/Shnaghai-7 (65%). The pathogen was also detected from the soil at maximum tillering stage under W-R-W cropping system and the collateral hosts such as Paspalum scrobiculatum, Panicum repens, Setaria italica, Phalaris minor and Panicum spp. growing in the vicinity of the experimental plots and Phalaris minor, which was growing in the experimental plot.