Influence of agronomic practice on foliar blight, and identification of alternate hosts in the rice-wheat cropping system
1998
Singh, R.V. | Singh, A.K. | Ahmad, R. | Singh, S.P. (N.D. University of Agriculture and Technololgy, Kumarganj, Faizabad, Uttar Pradesh (India). Dept. of Plant Pathology)
Foliar blight of wheat, caused mainly by Bipolaris sorokiniana and Alternaria triticina, adversely affects the crop, particularly under late sown conditions. Due to the prevalence of the rice-wheat cropping system and late rice harvest in eastern Uttar Pradesh, wheat is sown after mid December. The crop sown during late December coincides with foliar blight infection during late February and March, resulting in substantial yield losses. The influence of agronomic practice on foliar blight, and the identification of alternate hosts in the rice-wheat cropping system are presented. With less space between rows (15 cm), a high seed rate (125 kg ha-1), and full fertilizer dose (120:60:60 N:P:K),foliar blight intensity increased in comparison to wider spaced rows (23 am), a lower seed rate (100 kg ha-1), and half the fertilizer dose (60:30:30 N:P:K). An increased number of irrigation applications (6) and delayed sowing (after 30th November) increased foliar blight intensity compared with fewer irrigation applications (3) and timely sowing. Isolating fungi from potential hosts indicated that Phalaris minor harbors B. sorokiniana and A. alternata, while only A. alternata was isolated from Anagallis arvensis and Cannabis sativa. Alternaria alternata and A. triticina were isolated from Chenopodium album and Circium arvense. Only B. sorokiniana was pathogenic on both wheat and Phalaris minor, indicating that P. minor serves as an alternate host.
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