TY  - REP
AU  - Bijukachhe,B.
AU  - Duveiller,E.|Mercado,D.|Maraite,H.
ED  - Centro Internacional de Mejoramiento de Maíz y Trigo CIMMYT, Nepal (India)
TI  - Epidemiology of foliar blights (spot blotch and tan spot) of wheat in the plains bordering the Himalayas
PY  - 2004///
CY  - Kathmandu (Nepal)
PB  - CIMMYT
KW  - Disease control
KW  - Fungicides
KW  - Grain yield
KW  - Helminthosporium
KW  - Rice
KW  - AGROVOC
KW  - Seedlings
KW  - Weed control
KW  - Wheat
KW  - Genotypes
KW  - CIMMYT
KW  - UCL
N2  - Duveiller, E., Kandel, Y.R., Sharma, R.C., and Shrestha, S.M. 2004. Epidemiology of Foliar Blights (Spot Blotch and Tan Spot) of Wheat in the Plains Bordering the Himalayas. Phytopathology Helminthosporium leaf blight (HLB) caused by Cochliobolus sativus and Pyrenophora tritici- repentis is a serious constraint to wheat yields in the plains of South Asia. This study elucidates HLB development and its impact on yield. Analysis of disease progress showed the role of sowing time and growth stage on severity. C. sativus and P. tritici-repentis were first observed on leaves sampled at the seedling and tillering stages, respectively. Leaf infections progressed slowly for four to six weeks after sowing and then developed rapidly as mean temperature increased. Airborne conidia of C. sativus and P. tritici-repentis were observed seven weeks after emergence. They peaked close to harvest time, with C. sativus conidia outnumbering P; tritici-repentis. Seed infection is likely a source of primary inoculum. The disease caused an average 30% reduction in grain yield, with higher losses under delayed seeding. Increase in AUDPC per day or per degree-day better explained potential yield losses. This study using six contrasting genotypes is the first detailed report on the epidemiology of foliar blight pathogens in South Asia. Relative humidity and temperature favored the epidemic. The study shows the importance of combining crop management and genetic resistance for controlling HLB in the warmer wheat growing areas
ER  -