EFFECTS OF THREE VIRUS DISEASES AND THEIR COMBINATIONS ON FRUIT YIELD OF STRAWBERRIES

The results of a 5-yr study of the effect of virus diseases and virus disease combinations on fruit size and yield of strawberry (Fragaria × ananassa Duch.) are reported. The viruses causing veinbanding, latent C, and mottle, and combinations of veinbanding-latent C, veinbanding-mottle, and latent C-mottle were introduced into healthy and latent A-infected Redcoat plants. Runner plants from these were planted in the field and yield and size of fruit were recorded during the 1st, 2nd, and 3rd yr of production. In addition, a yield comparison was made of the cultivars Redcoat, Sparkle, and Catskill infected with the veinbanding-latent C complex. Fruit yield and size were affected by all virus diseases. Mottle virus caused little yield loss the 1st yr but reduced yield 11.5% the 3rd yr. The combination of veinbanding-latent C reduced yield 17.1% the 1st fruiting yr and 88.2% total fruit and 100% salable fruit the 3rd yr. Other viruses had intermediate effects.