The relationship between two-spotted spider mite and strawberry yield in canterbury

Abstract

Strawberry (cv. ‘Red Gauntlet’) yield was measured over two growing seasons, 1984 — 85 and 1985 — 86, in field experiments with a series of treatments involving two-spotted spider mite (TSSM) (Tetranychus urticae Koch), exclusion of predators and pesticide application. Two-spotted spider mite populations were much higher on first season plants than on older plants. Insecticides and miticides apparently play an important role in TSSM population regulation in first season plants but natural population regulation may be more important in populations on older plants. In their first season, plants yielded significantly less than second season plants, although mean berry weight was similar. The yield variation in plants of different ages cannot solely be attributable to seasonal affects. High, uncontrolled TSSM infestations in one season reduced yield in the following season but in the second season the yield variation between newly planted and established plants was still evident. Mite levels on established plants may not attain yield-reducing levels in Canterbury. Poor yields from new plantings may be due to treatment received by mother plants before runner lifting. © 1987 Taylor & Francis Group, LLC.