Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Abstract

Protection of sugar beet seed plant against Phoma betae (Frank): Part II. Effect of seed infection with P. betae on emergence and seedlings health.

Abstract

Effect of infection of 144 samples of sugar beet seeds with Phoma betae [Pleospora betae] in 1988, 1989 and 1990 was examined in field trials. The seed plants were sprayed with the fungicides: Sportak 45 EC (prochloraz 450 g/l) at the rate of 2 l/ha (S-2 seed samples) and 3 l/ha (S-3), and Oxafun T (thiram 37.5% and carboxin 37.5%) at the rate of 2 kg/ha (Z-2). The control seeds were from unsprayed plots. Overall intensity of infection ranged from 1.0 to 98.0% and that of deep-seated infection from 4.0 to 94.0%. Infection of the seeds harvested in 1988 and 1990 was heavier than of those harvested in 1989. The average number of emerged seedlings from control unsprayed plants was 63.4%, in Z-2 samples-68.9%, and in S-2 samples-70.3%. Emergence of the seedlings from S-3 and S-2 samples was similar. The activity of soil-borne pathogens was very high. The average number of healthy seedlings ranged in 1988 from 7.0 to 38.2% in 1989, from 9.8 to 13.8%, and in 1990 from 8.0 to 28.0%. In general the seedlings from S-2, S-3 and Z-2 plots were healthier than those from control plots. Moreover emergence of the seeds from S-2 and S-3 plots was higher than from control plots by 7.5% and 7.9% respectively, and the emerging plants were less susceptible to soil-borne pathogens. A significant negative correlation was found between intensity of seed infection with P. betae and field emergence in 1998 and 1990 and positive correlation between seedlings health in laboratory test and germination of seeds in the field in 1989 and 1990.