Effects of host, inoculum concentration, wetness duration, growth stage, and temperature on anthracnose of lentil

The effects of concentration of conidia, duration of the wetness period, pl ant growth stage, and temperature on the development of anthracnose (Collet otrichum truncatum) on lentil (Lens culinaris) were assessed in growth-cham ber and greenhouse studies using cv. Indianhead and line 458-57, which have partial resistance, and susceptible cv. Eston. Each genotype was assessed for incubation period (IP), latent period (LP), number of lesions (LN) per stem, and disease severity (DS). Both IP and LP decreased linearly with inc reasing conidial concentration, wetness duration, and temperature. Both IP and LP also became progressively shorter as the plants aged between 2 to 6 weeks and increased between 6 to 8 weeks after seeding. Both LN and DS incr eased linearly with increasing inoculum concentration, wetness duration, an d temperature. Both LN and DS also increased with plant age between 2 to 4 weeks and decreased between 4 to 8 weeks. The growth stage and temperature required for optimal disease development ranged, respectively, from 4 to 6 weeks and 20 to 24 degrees C when plants were inoculated at a concentration of 4 x 10(4) conidia/ml and provided with a wetness period of 24 h. Genera lly, cv. Indianhead and line 458-57 had significantly longer IP and LP and lower LN and DS than cv. Eston.