Aphid and whitefly resistance in Cucurbita; Uncovering potential sources of resistance and the possibility of broad-spectrum resistance to both insects

Aphids and whiteflies threaten the production of Cucurbita crops by causing damage through feeding and transfer of viruses. The cotton-melon aphid Aphis gossypii and the silverleaf whitefly Bemisia tabaci are two of the major species affecting Cucurbita. Current pest control heavily relies on chemical methods, but there is growing interest in exploring resistant crop varieties as an alternative strategy. To develop these resistant varieties, sources of resistance are needed. In search of potential resistant sources, we screened a total of 448 and 401 accessions in no-choice, clip-cage assays for resistance to A. gossypii and B. tabaci, respectively. The collection of accessions consisted of four of the cultivated species (C. argyrosperma, C. maxima, C. moschata, and C. pepo) and two wild relatives (C. ecuadorensis and C. lundelliana). By assessing survival and reproduction of the insects, we identified 44 accessions potentially resistant to A. gossypii and 16 accessions potentially resistant to B. tabaci, based on lower survival and reproduction. Accession PI 550694 showed resistance to both insects, which may indicate broad-spectrum resistance to phloem-feeding insects. These putative sources of resistance to aphids and whiteflies can be used for genetic mapping of resistance, contributing towards the development of resistant Cucurbita varieties.