Aphid parasitism and parasitoid diversity in cotton fields in Xinjiang, China

Abstract

Aphids are major pests of cotton crops in the Xinjiang Uygur Autonomous Region in China, and parasitoids are considered as important natural enemies in regulating aphid populations. However, information on aphid parasitoids in the Xinjiang cotton fields is limited, which hinders the study of aphid-parasitoid interactions and the application of conservation biological control against cotton aphids. In this study, a 3-year survey was conducted in a large geographical range that included three primary cotton planting areas in southern and northern Xinjiang. The population dynamics and the parasitism levels of an assemblage of aphids in the cotton fields were investigated along with the composition of the parasitoid community associated with these aphids. Aphid parasitization varied significantly within both years and seasons, with parasitism levels ranging from 0 to 26%, indicating that there is less effective biological control of parasitoids on aphids under field conditions. Among the primary parasitoids described, Binodoxys communis (Gahan) constituted 95.19% of the parasitoid species, followed by Praon barbatum Mackauer (3.15%), Trioxys asiaticus Telenga (1.01%) and Lysiphlebus fabarum Marshall (0.65%). Significant differences were found in the composition of the primary parasitoid species between the cotton seedling period (June) and the flowering period (July-August), and two more primary aphid parasitoids were found in the seedling period. Twelve hyperparasitoid species belonging to six genera were found in our study, of which Pachyneuron aphidis (Bouché), Syrphophagus species and Dendrocerus laticeps (Hedicke) were the dominant species. The composition of the hyperparasitoid community also differed significantly between the seedling and the flowering periods. The description of this parasitoid community-associated assemblage of aphids in cotton fields will facilitate the study of aphid-parasitoid interactions and promote the development of effective cotton aphid management strategies in Xinjiang.

Chromosome‐level genome assembly of the aphid parasitoid Aphidius gifuensis using Oxford Nanopore sequencing and Hi‐C technology

“…Aphidius gifuensis Ashmead (Hymenoptera: Braconidae) is a common endoparasitoid of many destructive aphid species (Figure 1), including Myzus persicae , Sitobion avenae and Schizaphis graminum (Pan & Liu, 2014). In China, this wasp has been widely bred and used as a biocontrol agent for more than four decades to control the green peach aphid, Myzus persicae , a severe pest on vegetables and tobaccos (Li et al, 2018; Yang et al, 2011). The life history, physiological characteristics, parasitic ability and breeding technology of A. gifuensis have been extensively studied to improve its captive breeding behaviour and aphid control efficiency (Khan et al, 2016; Li et al, 2013; Pan et al, 2018; Yang et al, 2009).…”

Intraguild Predation of Hippodamia variegata on Aphid Mummies in Cotton Field

“…Regarding aphid parasitoids in the cotton fields of Xinjiang, the population dynamics and parasitism rate of aphids have been investigated and the composition of the aphid parasitoid community has been determined (65% primary parasitoids, 35% hyperparasitoids). Among the four primary parasitoid species, the proportion of Binodoxys communis (Gahan) accounted for 95.19% [ 23 ]. However, up to now, there have been no reports of predation between H. variegata and aphid parasitoids.…”

Genome-wide identification and expression analysis of the GhIQD gene family in upland cotton (Gossypium hirsutum L.)

“…However, the production is greatly affected by abiotic and biotic stresses. For example, in China, aphid infestation has been found to reduce G. hirsutum L. production by 30% (Li et al 2018), and salt stress has been shown to decrease cotton fiber production by 20% (Shaban et al 2018). IQD proteins are CaMBPs that play an important role in plant stress signal transduction.…”