Comparison of six inoculation techniques with Colletotrichum acutatum on cold stored strawberry plants and screening for resistance to this fungus in French strawberry collections

Six inoculation techniques were compared for their ability to evaluate resistance to Colletotrichum acutatum of five strawberry cultivars. Inoculation by dipping the whole cold stored plants in a suspension of conidia adjusted to 2.10(6) conidia ml(-1) made it possible to screen cultivars resistant to crown rot at 28 days after inoculation. Using the dipping technique, 44 strawberry cultivars were evaluated for their resistance to one strain of C. acutatum, 1267b. Twelve of them did not show wilt symptoms and could be classified as resistant. When another strain of C. acutatum, 494a, was inoculated to seven cultivars, all of them including Dover, resistant to 1267b, showed wilt symptoms. This result showed the importance of investigations on genotype x isolate interactions to conduct an efficient breeding programme for screening resistance to C. acutatum.