Rw. Kieckhefer et al., YIELD OF SPRING WHEAT IN RELATION TO LEVEL OF INFESTATION BY GREENBUGS (HOMOPTERA, APHIDIDAE), Canadian Entomologist, 126(1), 1994, pp. 61-66
The effect of greenbug, Schizaphis graminum (Rondani), infestations on
yield components of early- and late-planted spring wheat, Triticum ae
stivum L., were measured in 2 successive years in eastern South Dakota
. Greenbug populations in plots generally increased rapidly and peaked
when wheat plants were in boot stage. Populations then began a steady
decrease until anthesis, at which time they were near zero. The numbe
r of seeds per spikelet and the number of spikelets per square metre w
ere consistently significantly negatively correlated with aphid-days,
whereas average seed weight was significantly negatively correlated wi
th aphid-days for only one planting. A linear regression model that in
cluded different intercepts for each spring wheat planting and a commo
n slope relating yield to greenbug feeding days (aphid-days) provided
a good fit to the data. Based on the model, a loss of 41 kg of grain p
er hectare is expected for each 100 aphid-days that accumulate per til
ler.