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Insect Vectored Bacterial Diseases Why is Greening so Difficult? Michael S. Irey Slide 2 2 Whats the big deal about insect vectored diseases? Many Insects Many Pathogens Many Diseases Many Mechanisms Slide 3 3 Vectors Aphids Thrips Mites Leaf hoppers Plant hoppers Tree hoppers Whiteflies Mealybugs Psyllids Flies Honey bees Beetles Leaf beetles Bark beetles Curculios Ants Slide 4 4 Pathogens Viruses Rhabdoviruses Geminiviruses Marafiviruses Waikaviruses Closteroviruses Tenuiviruses Phytoreoviruses Luteoviruses Poleroviruses Tospoviruses Potyviruses .....Many more Fungi Phytoplasmas Spiroplasmas Bacteria Stewarts wilt of corn Fire blight of apple Xylella diseases Pierces disease Almond leaf scorch Plum leaf scald Phony peach Coffee leaf scorch CVC Slide 5 5 Mechanisms Foregut-borne (nonpersistent, semipersistent) very short retention time (24-48 hrs), lost at molt no latent period, retained in the foregut Circulative (persistent, non-propagative) retention time up to several weeks, not lost at molt latent period, retained in body (hemocoel, organs) Propagative (persistent, propagative) retention time up to life of insect, not lost at molt latent period of several days weeks retained in body (hemocoel, organs) Non-circulative No latent period, lost at molt, retained in foregut for life of the insect, doesnt circulate in body Surface Slide 6 6 Diseases Barley Yellow Dwarf Viral (BYDV) Most economically important virus in cereals Control vector control on a regional basis Cereal aphids Persistent circulative Slide 7 7 Diseases Pierces disease (grapes) Bacterial Limiting in Florida Control vector control on a regional basis Glassy Winged Sharpshooter Persistent Slide 8 8 Examples Fire Blight Bacterial Control IPM (pruning, insect control, resistance, etc.) Bees Surface Slide 9 9 Examples - Citrus Leprosis/MiteCitrus Tristeza Virus/Aphid Slide 10 10 Examples - Citrus Citrus Stubborn/Leafhoppers CVC/Leafhoppers Slide 11 Huanglongbing Slide 12 12 Candidatus Liberibacter asiaticus heat-tolerant, produces symptoms in either warm or cool climates Candidatus Liberibacter africanus (Africa) heat-sensitive, produces symptoms in cool climates (