Influence of calcium nutrition on wilt of dry bean

Abstract

The influence of calcium nutrition in hydroponic solution on the severity of Fusarium wilt of beans, as well as the influence of concentration and type of inoculum on infection, was studied under green house conditions. Chlamydospores (10³, 10⁴, 10⁵/ml) or conidia (10⁴, 10⁵, 10⁶/ml) were inoculated in susceptible plants of 1 week age to verify the influence of concentration and inoculum type on the severity of Fusarium wilt. Disease severity, evaluated after 20 days, was related with inoculum concentration. Chlamydospores were more infective than conidia. The interaction between Ca concentration and severity of Fusarium wilt was investigated by inoculating one-week old susceptible and resistant plants with 10³ chlamydospores/ml. The plants were grown in solution containing 0.3; 0.5; 1.0; 2.0; 3.0 and 4.0 mN of Ca. Disease severity and vascular discoloration were evaluated after 20 days. The content of micro and macro nutrients were determined in the plant tops. No correlation between tissue Ca and disease severity or vascular discoloration was observed.