Occurrence of raspberry gall midge Lasioptera rubi Schrank (Diptera, Cecidomyiidae) in some raspberry cultivars

Abstract

The raspberry gall midge, Lasioptera rubi Schrank (Diptera, Cecidomyiidae), is an economically important pest, especially in the raspberry plantings where canes are not removed after harvest. The objective of this study was to determine the harmfulness of L. rubi in an untreated raspberry cultivar planting at the Fruit Research Institute, Serbia.

Cane samples were collected in July 2008 from five raspberry genotypes, including cvs. Willamette, Meeker, Latham, Tullameen and the hybrid K 81-6, to assess raspberry gall midge infestation. The samples were sent to the laboratory to be measured for cane diameter and gall length, width and diameter and checked for the number of galls per cane and larvae per gall.

Galls did not occur in cv. Meeker, but they were found on the primocanes of the other cultivars at a height not exceeding 70 cm. The largest average number of infested canes (10) was recorded in the K 81-6 hybrid. The detected galls differed in shape, the largest being observed in Tullameen, somewhat smaller in K 81-6 and those of similar size in Latham and Willamette. The highest larval pressure per gall (40) was recorded in cv. Tullameen. The presence of young and old larvae as well as eggs was observed in the globules in cvs. Tullameen and K 81-6. The calculated values for 2008 show that the highest larval/gall pressure was found in Tullameen (24.5) and lowest in Latham (5.28).

The most vigorous canes were observed in Willamette, followed by Latham, K 81-6 and Tullameen.