Effect of Soy Leaf Flavonoids on Pea Aphid Probing Behavior

Area of Science:

• Agricultural Science
• Entomology
• Plant Biochemistry

Background:

• Soybean (Glycine max) flavonoids impact insect herbivores.
• Pea aphid (Acyrthosiphon pisum) is a significant threat to soybean crops.
• Individual flavonoid effects on pea aphid feeding behavior are not well understood.

Purpose of the Study:

• To investigate the impact of specific flavonoids (apigenin, daidzein, genistein, kaempferol) on the feeding behavior of the pea aphid, Acyrthosiphon pisum.
• To understand how these flavonoids influence probing activities and sap ingestion within host plants.

Main Methods:

• Utilized the electrical penetration graph (EPG) technique to monitor aphid stylet activities.
• Assessed probing behavior of Acyrthosiphon pisum on pea plants treated with ethanolic flavonoid solutions.
• Compared feeding behavior on control plants versus plants treated with apigenin, daidzein, genistein, and kaempferol.

Main Results:

• No flavonoids affected the initial probing propensity of Acyrthosiphon pisum.
• Apigenin increased non-phloem probing and xylem ingestion while limiting phloem ingestion.
• Daidzein delayed phloem access and reduced sap ingestion; kaempferol reduced phloem phase duration.
• Genistein showed no significant effect on aphid feeding behavior.

Conclusions:

• Individual flavonoids differentially modulate pea aphid feeding behavior, affecting stylet activities and sap ingestion.
• Findings offer valuable data for breeding soybean cultivars with enhanced resistance to Acyrthosiphon pisum.
• Understanding flavonoid-plant-aphid interactions is crucial for sustainable pest management strategies.