Electrical penetration graph monitored feeding behavior of cowpea aphid, Aphis craccivora (Hemiptera: Aphididae), on faba bean, Vicia faba, cultivars

Feeding behavior of cowpea aphid, Aphis craccivora Koch., was evaluated on five faba bean, Vicia faba L., cultivars, including the resistant cultivar Gazira2, by using the Electrical Penetration Graph (EPG) technique. Experiments were conducted on whole plants (WP) and detached leaves (DL). Fifteen parameters of EPG recordings were selected for statistical analysis. Two-way factorial ANOVA showed that the EPG parameters values in WP and DL were significantly different, while the cultivars difference occurred mostly in the WP tissue as indicated through one-way ANOVA Kruskal-wallis analysis. Cowpea aphid feeding behavior on WP Gazira2 resistant cultivar had the longest duration of stylet derailment (waveform F) and total probing, but lowest in total duration of pathway (waveform C), xylem ingestion (waveform G), and number of probes. Speculatively, longest duration of waveform F, that was lost in DL, might be the possible resistant factor in Gazira2 which might had relation with the mechanical disturbance during feeding, however this remains intriguing and needs further study.