Abundance of twospotted spider mites and Neoseiulus californicus on strawberry varieties in organic production

Strawberry is an economically important small fruit crop in the United States with yields exceeding 36 billion pounds during 2012. Florida is the second highest producing state in the country. Organic strawberry production is increasing in the southeastern states and strawberry varieties need to be identified for use in this type of production system. In order to support the development of organic strawberry production in Florida and other southeastern states, we studied the susceptibility of strawberry varieties to twospotted spider mites (TSSM), Tetranychus urticae Koch, and assessed the performance of Neoseiulus californicus(McGregor) on strawberry varieties for management of TSSM population. In 2014-2015 growing season, three varieties, namely Festival, Sensation and Winterstar were planted in the open field, in a randomized complete block design with four replicates. Sampling was done weekly over a 19-week period. Data were analyzed using repeated measures ANOVA, and LSD was used to separate treatment differences. Statistical differences were observed in TSSM population among the varieties in week 17, Festival supported the highest TSSM population. Neoseiulus californicus population was low until late season, with significant differences observed in weeks 17 and 18. In general, none of the varieties performed significantly better than the others in harboring TSSM. However, the abundance of TSSM on the varieties may serve as a tool to select varieties that can potentially perform well under organic production techniques.