POTATO LEAFHOPPER (HOMOPTERA, CICADELLIDAE) FEEDING DISRUPTION OF PHLOEM TRANSLOCATION IN ALFALFA

Compared the distriobution of radioactive, CO2-derived photosynthate in Empoasca fabae leaf-hopper-injured and healthy (uninjured) Medicago sativa stems. Exposure to 2 adult potato leafhoppers confined for 3d on the top 10 cm of alfalfa stems, reduced the upward flow of labeled translocate to the stem tips 300-fold and produced an accumulation of assimilates in the lower stem 2.4 times that of uninjured stems. Similar disruptions of translocation were achieved by caging two leafhopper adults for >6 h to the 4th internodes of stems. Stem exposure for these shorter durations resulted in a 3.7-fold decrease in photosynthate at the tips of injured stems. -from Authors