Investigation on the Relationship between Morphological and Anatomical Characteristic of Savoy Cabbage and Kale Leaves and Infestation by Cabbage Whitefly (Aleyrodes proletella L.)

The cabbage whitefly (CW), Aleyrodes proletella (L.) (Hemiptera: Aleyrodidae), is an important pest in Brassica oleracea L. crops. Little is known about the mechanisms of resistance to CW of savoy cabbage and kale cultivars. Light microscopy (LM) and scanning electron microscopy (SEM) analysis were used to determine the relationship between the morphological and anatomical features of savoy cabbage (Brassica oleracea L. convar. capitata (L.) Alef. var. sabauda L.) and kale (Brassica oleracea L. convar. acephala (DC.) Alef. var. sabellica L.) leaves and host suitability to colonization by CW. Two kale cultivars, Redbor and Starbor, and two savoy cabbage cultivars, Gloriosa and Alcosa, that differed in the degree of infestation by A. proletella were taken for histological analysis. The lowest infestation by all forms of A. proletella was observed on savoy cabbage cultivar Alcosa and kale cultivar Starbor. The reduced colonization by cabbage whitefly may be related to the structure of the epidermis and the anatomical features of the leaf. The leaves of Starbor and Alcosa had more folds in the epidermis, less numerous but larger stomata, and a more compact mesophyll structure compared to Redbor and Gloriosa. In both analysed species, there was no clear relationship between the thickness of the abaxial epidermal layer, thickness of the lamina, number of vascular bundles, and degree of infestation by the cabbage whitefly. This study identified promising sources of resistance to A. proletella among cultivars of savoy cabbage and kale. Varying infestation by CW was associated with morphological and anatomical characteristics of leaves. Further study is needed to confirm the relationship between insect resistance and leaf surface and morphological characteristics of leaves in a broader range of Brassica spp.

Automated summary

This study analyzed the morphological and anatomical characteristics of savoy cabbage and kale leaves in relation to their resistance to the cabbage whitefly. Promising sources of resistance to A. proletella were identified among cultivars of savoy cabbage and kale. Further research is needed to confirm the relationship between insect resistance and leaf surface and morphological characteristics in a wider range of Brassica spp.