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Oral: The Impact of Vector-Borne Bacteria Pathogen on Associated Hosts


Reducing Hemipteran Vectors and pathogen spread, Topically applied RNAi.
W. HUNTER (1), E. Andrade (2) (1) USDA-ARS, U.S.A.; (2) EMBRAPA, Cassava & Fruits, Brazil

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Topically applied, non-transgenic method for RNAi in plants provides a highly specific mechanism to target a single specie. RNAi on hemipterans, Asian citrus psyllid, and glassy-winged sharpshooter show promising results. The psyllid transmits deadly plant-infecting bacterium of citrus trees, Citrus Greening Disease, aka. Huanglongbing. Leafhoppers transmit X. fastidiosa bacteria, Pierce’s Disease of grapevines. Ingestion of specific dsRNA showed specie specific suppression, and increased mortality. Bioassays of cut plant tissue, or potted seedlings, with 10 to 100ng dsRNA were tested. Trials of 8 cages or seedlings/treatment, with 20 adults, or 50-100 psyllid/tree. Negative Control dsRNA was GFP. Mortality across 12-17 days, began on 5d post feeding. Mortality rates varied for dsRNAs from 10-100%. The dsRNAs induced significant insect mortality over controls, and was safely ingested by honey bees, Apis mellifera. RNAi continues to show potential as a means of specific insect pest management.