Comparative analysis of aphid vector behavior in response to potato plantsgrown from field tubers, minitubers or plantlets

The greater sensitivity to aphid vectored diseases of potato plants origina ting from plantlets or mini-tubers compared to plants originating from fiel d grown tubers could not be explained by changes in probing behavior, by in creased aphid movement between plants or by greater levels of aphid coloniz ation favorable to virus spread. The number of seconds to first probe, the duration and number of seconds before the long probe and the duration of th e long probe were statistically similar on all plant types. The average res idency time of green peach aphids on each plant type was also statistically the same. Winged Myzus persicae (Sulzer) (green peach aphid) landed in gre ater numbers on older than on younger plants regardless of plant type. This suggests that the level of aphid colonization is determined by a combinati on of factors such as height, surface and age of plants but not by plant or igin. Where virus vectors are present early in the season, the greater numb er of aphids landing on the relatively older and larger transplants may con tribute to higher infection levels, but later in the season plant physiolog ical factors favorable to virus multiplication or translocation are more li kely factors.