GUAZATINE PLUS AS A SEED TREATMENT BACTERICIDE TO ERADICATE XANTHOMONAS-CAMPESTRIS PV UNDULOSA FROM WHEAT SEEDS

Efficiency of Guazatine Plus as a seed treatment bactericide to eradicate Xanthomonas campestris pv. undulosa from wheat seeds was evaluated in the laboratory and in field conditions during three years. Guazatine Plus had a bactericidal property against five pathovars of X. campestris including undulosa at concentrations of over 200 ppm, but had no action against two pathovars of Pseudomonas syringae and one strain of Erwinia chrysanthemi. Field experiments were conducted in 1987, 1988 and 1989 using seeds of 3, 19 and 31 wheat varieties respectively, with varying levels of bacterial contamination. The bactericide reduced the disease severity and,increased yields up to 39.7% depending upon the wheat variety and the level of bacterial contamination in the seed. Reduction in yield as a result of disease was due to a decrease in grain weight; the number of grains per spike was not affected by the severity of the disease. On average, reduction in yield was proportional to the increase in disease severity.