2.8.25
ASSESSMENT OF LOSSES IN GRAIN YIELD DUE TO STAGHEAD PHASE OF WHITE RUST ALBUGO CANDIDA OF RAPE SEED AND MUSTARD

MS SANGWAN, JK DANG and CD KAUSHIK

CCS Haryana Agricultural University, Hisar-125 004, Haryana, India

Background and objectives
White rust of rape seed and mustard caused by Albugo candida is one of the most important factors limiting its production. It has a world-wide in distribution and probably affects every cruciferous crop. Systemic infection (staghead) causes hypertrophy and hyperplasia of inflorescence and contributes to heavy losses in grain yield [1,2]. Studies were, therefore, undertaken to assess the losses caused by staghead infection in different cultivars of rapeseed and mustard sown on different dates.

Materials and methods
Four cvs, namrly RH-30, RH-81 13 Brassica juncea YSPb-24 and BSH-i B. ;campestris were sown on 14 and 24 October, and 4 and 17 November during the crop season of 1993-94. The crop was sown in plot size of 3.0X2.10 ;m with 30 ;cm between rows and 10 ;cm plant to plant, with three replications in a randomized block design. The length of healthy branch corresponding to malformed branch was measured. Grain yield of healthy branches and yield/plant were taken to calculate the losses in grain yield due to staghead infection.

Results and conclusions
Maximum disease intensity of staghead was observed in RH-30 and minimum in BSH-1 in all the four dates of sowing. Among the four cultivars, highest loss in grain yield was recorded in RH-30 (10.5%) followed by RH-81 13 (7.6%) in the crop sown on 4 November compared with YSPb-24 (3.2%) and BSH-1 (1.5%). The losses were minimum in the first date of sowing in all the four cultivars; however, the maximum was recorded in RH-30 (3.4%) and the minimum in BSH-1 (0.71%).

The studies reveal that early-sown crop escapes staghead infection, resulting in minimum loss in grain yield.

References
1. Petrie GA, 1973. Canadian Plant Disease Survey 53, 19-25.
2. Lakra BS, Saharan GS, 1987. Indian Journal of Mycology and Plant Pathology 19, 279-281.