DEVELOPMENT OF 2 SPOTTED SPIDER-MITE (ACARI, TETRANYCHIDAE) POPULATIONS ON STRAWBERRY AND RASPBERRY CULTIVARS

Five strawberry (Fragaria sp.) and five raspberry (Rubus ideaus L.) cu ltivars were evaluated for resistance to two spotted spider mite (Tetr anychus urticae Koch.). Two methods of assessing the development of tw o spotted mite populations using detached leaves were compared. The nu mber of eggs laid and mites which developed were compared. The strawbe rry cvs Hapil and Pegasus had significantly greater development of two spotted mite populations than the cvs Rhapsody, Symphony and Elsanta. The raspberry cv. Joan Squires had higher populations of two spotted mite whilst the raspberry cv. Leo the least, when compared with cvs Gl en Clova, Glen Moy and Glen Prosen. Differences were observed in ovipo sition sites and mite distribution when comparing raspberries with str awberries. The method of assessing the populations development of two spotted mite which involved maintaining the cut leaf stem in water may be of potential use for studying population dynamics of both two spot ted mite and possible predators over extended periods of time.