Phaedon cochleariae (F.) performance on different crucifer varieties with different glucosinolate profiles

Area of Science:

• Agricultural Entomology
• Plant-Insect Interactions
• Chemical Ecology

Background:

• The mustard leaf beetle (Phaedon cochleariae) is a significant pest of cruciferous crops in Europe.
• Glucosinolates (GS) are secondary metabolites in crucifers that can influence insect herbivory.

Purpose of the Study:

• To investigate the feeding and oviposition performance of Phaedon cochleariae on six different crucifer cultivars.
• To determine the relationship between glucosinolate profiles and beetle performance on these cultivars.

Main Methods:

• Larval weight increase over seven days was measured on six crucifer cultivars.
• Adult oviposition (egg-laying) was quantified over three days on three selected cultivars.
• Glucosinolate (GS) profiles of the tested cultivars were considered in relation to beetle performance.

Main Results:

• Larval weight increase varied significantly among cultivars, with highest gains on Brassica chinensis cultivars having low GS content.
• Larval performance was better on cultivars with indolyl and aliphatic GS (e.g., B. chinensis, Raphanus sativus) and poor on those with aromatic GS (mustard).
• Oviposition was highest on B. chinensis 'Joi Choi', followed by Raphanus sativus and Sinapis alba, correlating with GS profiles.

Conclusions:

• Glucosinolate profiles significantly influence both larval growth and adult oviposition of the mustard leaf beetle.
• Indolyl GS, abundant in B. chinensis, may stimulate oviposition more than aromatic or aliphatic GS.
• Cultivar selection based on GS content could be a strategy for managing Phaedon cochleariae infestations.