Feeding behavior of Brevicoryne brassicae in resistant and susceptible collard greens genotypes: interactions among morphological and chemical factors

Abstract

The cabbage aphid, Brevicoryne brassicae (L.) (Hemiptera: Aphididae), is distributed throughout the tropical and subtropical areas of the world. The main crops attacked by B. brassicae are cabbage, collard greens, broccoli, Brussels sprouts, and cauliflower. To survive the attack of pest insects, plants have evolved various resistance mechanisms that may affect pest feeding behavior. The use of electronic monitoring through EPG (electrical penetration graph) can help characterize and distinguish the resistance mechanisms involved. This study evaluated the feeding behavior of B. brassicae in eight genotypes of collard greens, Brassica oleraceae L. var. acephala (Brassicaceae), exhibiting antixenosis and/or antibiosis resistance to this insect. Possible correlations were established between the glucosinolate levels, the hardness, and the epicuticular wax on the leaves vs. aphid feeding behavior. On the genotypes 22V, 5E, and 27VA, for which many 'potential drop' waves were performed, aphid development was slower, indicating antixenosis as resistance type. Aphids on the genotypes 22V and 24X required more time until accessing the phloem, also suggesting antixenosis as resistance category. Genotypes 22V and PE had hard leaves, which also points at antixenosis. Genotypes 20T and HS had higher total wax and wax mg À1 . Feeding parameters on ARI and 24X were similar to those observed on HS; antibiosis is likely to be the predominant resistance category of this germplasm. Because HS was considered as a susceptible standard genotype in this study, a higher gluconapin amount indicates that this compound does not influence cabbage aphid feeding behavior. The present study confirms that analysis of the physical and chemical aspects of collard greens genotypes by the EPG technique can provide a useful approach for the study of plant resistance to cabbage aphids.

Nymphal Performance and Fecundity of Melanaphis sacchari (Zehntner) (Hemiptera: Aphididae) in Different Sorghum Genotypes

“…The colonization of aphids on host plants can be influenced by several chemical and morphological causes, as already reported for crops such as collard greens, where the content of glucosinolates, amount of wax on the leaf cuticle, and leaf hardness are determinant factors of resistance against Brevycorine brassicae (L.) (Hemiptera: Aphididae) [17]. In tomato plants, the presence of glandular trichomes and the high contents of acyl sugars or 2-tridecanone is directly related to the failure of Myzus persicae (Sulzer) (Hemiptera: Aphididae) colonization [21], while in cotton, the gossypol content and the pilosity of the structures directly influences the infestation of Aphys gossipii (Glover) (Hemiptera: Aphididae) and feeding of Helicoverpa armigera Hübner (Lepidoptera: Noctuidae) in the different genotypes [22,23].…”

“…Plants were watered every 48 h by submerging the rack of cones in a water bath for 30 min. The assessments of aphid performance have typically involved the observation of solitary aphid nymphs developing in clip cages, and the daily harvesting of nymphs to tally their fecundity [17]. However, because many aphid species are naturally gregarious, solitary development and reproduction may represent hardship and can potentially lead to underestimates of biological performance.…”

“…The solutions obtained (wax + chloroform) evaporated in an exhaust hood to obtain the solid residue (wax). After complete evaporation, the beakers were reweighed and the wax content was determined as a function of the mass difference [17].…”

Aphis spiraecola and Aphis (Toxoptera) citricidus differently manipulate plant metabolism to gain fitness in terms of population abundance or dispersal

“…Here, in comparison with A. citricidus, A. spiraecola infestation was associated with a higher number of pathway phase activities and intracellular punctures, and A. spiraecola spent more time in the stylet pathway phase and reached the phloem sap slower. These parameters indicated a delay during reaching of the phloem, which suggests a stronger antixenosis resistance type (i.e., insect behavior was negatively affected when it attempted to gain access of the plant phloem) (Canassa et al, 2020). In addition to the difficulty in gaining access and acceptance of phloem sap, A. spiraecola also spent shorter time on phloem sap ingestion compared with A. citricidus.…”

Opening the Treasure Chest: The Current Status of Research on Brassica oleracea and B. rapa Vegetables From ex situ Germplasm Collections

“…Plant resistance tests of eight genotypes of collard greens ( B. oleraceae var. acephala ) against cabbage aphid revealed an interactive effect of biochemical and morphological resistance mechanisms ( Canassa et al, 2020 ). Sources of resistance against cabbage moth were detected in a screen of 21 local and commercial cabbage varieties and interactive effects of leaf traits, head compactness, and leaf glucosinolate content were identified ( Cartea et al, 2010 ).…”