PRELIMINARY NOTES ON THE LIFE HISTORY AND 
CONTROL OF THE: POTATO LEAE-HOERIR: 
Empoasca mali LeB.* 
by 
A. Gz RUGGEES AND. Js Ke Dyer 
Life History 
Food plants—The food plants of the potato leaf-hopper as de- 
termined from observation at University Farm in 1922 are potato, 
apple, box elder, blackberry, raspberry, curly dock (umes crispus L.), 
rhubarb, and dahlia. Development of the first brood takes place almost 
exclusively on potato, while the second brood may develop on any 
of these plants, altho potato is preferred. The adults feed indiscrim- 
inately on all these food plants when potato is not available. 
Overwintering -adults——Observations on the overwintering habits 
of the potato leaf-hopper in Minnesota showed that only the adult 
stage survived the winter. In 1922, following a heavy frost on 
October 12, adults began to leave their food plants to hunt for hiber- 
nating quarters. They had completely disappeared from the fields by 
November 15. Individuals feeding on potato in the greenhouse left 
the plants at approximately the same date and hibernated beneath dead 
vegetation and flower pots. In 1922, adults began to come out of 
hibernation the latter part of May and to feed on box elder and black- 
berry. They were first observed on early potatoes June 7 and became 
quite abundant about the middle of the month. 
First generation.—Small numbers of eggs were found in the stems 
and midribs of potato leaves about June 12, increasing in abundance 
toward the latter part of the month. The nymphs hatching from these 
eggs required an average of twenty days for development, changing 
to adults late in July. 
Second generation—The adults of the first generation became 
most abundant in August and lived from 25 to 50 days. The egg 
laying of these adults was continued from the latter part of July until 
early October. 
The nymphs hatching from these eggs required about 30 days 
for development. Those hatching late in September did not develop 
1 Published with the approval of the director as Paper No. 390 of the Journal Series 
pf the Agricultural Experiment Station. 
