Fungal pathogens in rotted basal leaves of lettuce in Humberside and Lancashire with particular reference to Rhizoctonia solani

Abstract

Rhizoctonia solani was an important though erratically occurring pathogen of protected lettuce but was unimportant in outdoor crops. The most common fungal pathogen in rotted basal leaves of both protected and outdoor lettuce in Humberside and Lancashire was Botrytis cinerea. Sclerotinia sclerotiorum was common in leaves of outdoor lettuce in Lancashire but was encountered infrequently in protected crops in Humberside, Of 27 isoJates of R. solani which were tested for anastomosis group. 11 were AG‐L 13 were AG‐2 type I. two were AG‐2 and one was AG‐4. The AG‐4 isolate had a Thanatephorus praticola teleomorph whereas representatives from the other groups were Thanatephorus cucumeris.