Characteristics of feeding behaviors of Myzus persicae (Hemiptera: Aphididae) depending on inflow concentrations of dinotefuran.

The changes of feeding pattern and the amount of insecticide penetrated into the leaf were monitored for 420 min after treatment of three concentrations of dinotefuran. At about 30 min after treatment of insecticide, the overall feeding pattern in EPG (Electrical Penetration Graph) monitoring was started to change, and there was significant difference in proportions of NP (non-penetration), PA (pathway activity), and phloem-feeding patterns among the different concentrations of dinotefuran treatment. Especially, as the amount of insecticide penetrated into a leaf increased, the reactive behaviors against this insecticide such as withdrawal of proboscis and movements of stylet of aphid were more quickly exhibited. And also, total time at which the proboscis of the aphids did not penetrate the plant was getting longer. The amount of dinotefuran penetrated into a leaf was monitored with HPLC. When the recommended concentration (100 mg/L) of the insecticide was treated, 5.247.24 mg/L of the insecticide was detected from the leaf, and the proboscis of the aphids was apparently withdrawn from the leaf at approximately 60 minutes after treatment of this insecticide.