Evaluating resistance in selected cranberry varieties towards Sparganothis fruitworm (Sparganothis sulfureana).

Host plant resistance, an important strategy of Integrated Pest Management, was examined in the American Cranberry, Vaccinium macrocarpon Ait. (Ericaceae). This study assessed larval development and adult oviposition preference of one of the most economically important pest species in Wisconsin: sparganothis fruitworm, Sparganothis sulfureana (Clemens) (Lepidoptera: Tortricidae), in five different cranberry varieties, i.e. Stevens, Ben Lear, GH-1, Mullica Queen, and HyRed. Neonate larvae from a laboratory colony were placed on clipped uprights of each of the five cranberry varieties, and allowed to develop to pupation, at which point their weight, development time, and amount of leaf matter consumed was measured. To gauge oviposition preference among different varieties, virgin female and male moths were released in small enclosures containing a choice of potted plants on which to oviposit: a Stevens variety cranberry plant, a second variety of cranberry plant, and an alternative host plant, alfalfa. After oviposition occurred, eggs and egg masses on each plant were counted. This research will complete an assessment of whether certain varieties are more resistant than others, and elucidate possible mechanisms of resistance. A more resistant variety could be incorporated into future plantings and breeding programs, ultimately reducing the need for chemical control of this pest.