Using infrared transducers to sense greenbug (Homoptera: Aphididae) infestations in winter wheat

摘要

Winter wheat was grown under four regimes (normally-watered, and not infested, normally-watered and infested, water-stressed but not infested, and infested and water-stressed) to determine if infrared transducers (IRTs) could be used sense greenbug(Schizaphis graminum) infestations and distinguish them from water stress. The IRTs were able to sense temperature differences among plants of the different treatments, and when the IRT data were converted to differences from ambient temperatures, significant differences were found among the treatments. When sampled at 09.00 h, plants undergoing water stress and infested with greenbugs were always significantly warmer (p=0.05) than normally-watered, noninfested plants. Temperatures of plants either water stressed or infested by greenbugs were between these extremes and were not statistically distinguishable from each other. However, on several occasions, they could be distinguished from nonstressed plants and those stressed by both factors. Analysis ofgreenbug abundance and temperature differences between normally-watered and water-stressed plants resulted in two significantly-different regressions that were nearly parallel, indicating that, within natural parameters, there may be a constant ratio between damage by greenbug and water stress in wheat. In conclusion, IRTs were found not to be a tool that can be used alone to distinguish greenbug infestations in winter wheat. Unless certain water stress conditions are met (absence or uniform), there isno practical way to differentiate greenbug infestations from water stress in winter wheat.