D3080: Impacts on inoculum kinetics: Environmental variation influencing arthropod vector feeding behavior

Plant health and crop productivity are influenced by the interactions between plants, pathogenic microbes, insect vectors, and the environment. Insect vectors are critical in transmitting pathogens, affecting crop yields, and influencing crop and non-crop plant population dynamics. In this study, Electropenetrography (EPG) is used to observe insect feeding behavior under environmental conditions manipulated to simulate patterns in the fluctuation of temperature or moisture. Environmental effects are then linked to pathogen transmission by affected insect vectors, to explain variation in plant disease epidemic dynamics as a function of environmental variation. This approach enables the modeling of abiotic factors on each of several processes relevant to plant-vector-pathogen phenology and dynamics mediated by feeding. To relate feeding behavior to inoculum dynamics, a digital PCR platform is used, where quantification of inoculum is conducted for plant tissue at small scale, or for individual vectors under controlled treatments. Initial results in aphid and mealybug systems show that quantitative variation among waveforms of a given classification is repeatably detectable. The aim of this work is to improve understanding of the mechanisms of plant disease transmission by vectors and integrate this understanding into plant disease epidemiological models for study and management. These findings will enable prediction of disease transmission that may depend on abiotic inputs in multiple ways; for example, heat’s different effects on plant stress (elevated) vs. vector physiological development (accelerated) vs. vector feeding (to be determined). An important outcome of this work will be the identification of environmental limits at which behavior mitigation is defeated.