Organic fruit and vegetable growing is increasing world-wide, but knowledge concerning best practice is generally empirical rather than field-based. This thesis extends knowledge concerning best practice in Swedish organic strawberry (Fragaria x ananassa (Duch)) production, which is usually based on a two-year crop. A series of four field experiments were conducted at Rånna Experimental Station (58°27’N, 13°51’E) on the strawberry cultivars ‘Honeoye’, ‘Cavendish’ and ‘Korona’. Specific objectives were to investigate: the effects of different organic fertilisers combined with degradable plastic mulch on plant establishment, yield and nitrogen mineralisation in soil; the efficiency of biological pest control using a predatory mite against strawberry mites (Phytonemus pallidus); innate within-field dispersal capacity of strawberry mite; the effects of pyrethrum combined with fleece covering on damage by strawberry blossom weevil (Anthonomus rubi). Plant establishment measured as fruit yield was improved by 60% when degradable plastic mulch was used, probably through more flowers being initiated. Additional applications of organic fertiliser during the cropping period had little effect on yield. Biological control using the predatory mite Neoseiulus cucumeris reduced strawberry mite populations by up to 50% but there was no increase in yield. It was difficult to draw clear conclusions from the strawberry mite dispersal pilot study, but mites tended to move more easily along planted rows than between rows. Pyrethrum alone had no visible effect on flower bud damage by strawberry blossom weevil but when combined with fleece covering it reduced the number of ‘Honeoye’ buds damaged by weevils by approximately 10%. This was followed by a corresponding increase in cultivar yield. Similar effects were not recorded in the other cultivar examined. The study identified the following practical consequences for organic strawberry production: • Choice of pest-resistant cultivars is extremely important for success. • Use of clean plants and an efficient predatory species is essential in controlling mite infestations. • Use of degradable plastic mulching is recommended. • Fleece covering is recommended for protecting some cultivars against strawberry blossom weevils. • Only an initial starter fertilisation is required. • Use of pyrethrum is not recommended
