Genetic Resistance to Currant Borer in RibesCultivars

Abstract

The larvae of the currant borer ( Synanthedon tipuliformisClerck), a clearwing moth, are pests of cultivated black, red, and white currants ( RibesL.) throughout the world. While broad-spectrum insecticides are the standard control, more environmentally friendly techniques, such as mating disruption using synthetic pheromones, can be successful. Genetic resistance is not extensively reported or employed as a pest control strategy. We screened 150 diverse black ( Ribessubgenus: Ribes section: Botrycarpum), red and white currants ( Ribessubgenus: Ribes section: Ribes) at the U. S. Department of Agriculture, Agricultural Research Service, National Clonal Germplasm Repository-Corvallis (NCGR), for natural infestation by currant borer. Dependent on stem availability 130 dormant canes (about 20 cm) were collected. Canes were cut transversely, and dissected longitudinally. In highly infested black currant cultivars, such as R. nigrumL. ‘Silvergeters Zwarte,’ 2 or 3 larvae were observed within one cane. The R. nigrum‘Black Naples’ derivatives, ‘Saunders’ and ‘Kerry’, had low larval counts, although ‘Neosypaushayasya’ was highly infested. Some black currant cultivars from Northern Sweden, Russia, and England had low counts. Cane borer larvae were not observed in any of the pink or white flowering currants, Ribes sanguineumPursh or in golden currants, R. aureum var. villosacvs. Crandall, Idaho or Gwens. Red currant hybrid cultivars with a complex pedigree containing R. rubrumwith R. multiflorumKit. ex Schult. cvs. Detvan, Mulka, Redstart, Rolan, Rosetta, Rondom, and Rovada, had low larval counts, although others of similar background, such as ‘Blanka’, were highly infested. The infestation frequency of the samples described a negative exponential function rather than a normal distribution.