Factors influencing the establishment of latent infection of narrow-leafed lupins by Diaporthe toxica

Abstract

Inoculation of a susceptible cultivar of lupin (Lupinus angustifolius cultivar Yandee) with pycnidioconidia of Diaporthe toxica was carried out in the glasshouse to evaluate the effects of simulated dew period, inoculum concentration, temperature of incubation and host tissue maturity on infection using the assessment of the latent infection structures as the assay method. Optimum infection occurred after a dew period of 72 h. Infection was highest at inoculum levels between 1 x l05 and 1 x l07 and at 20¦C. One-week-old stem tissues were most susceptible to infection with very few infections evident on 10 week old tissues.