ven2lecc19_(pestdiseases)

ven2lecc19_(pestdiseases) - VEN 2 Pests and Diseases Grape...

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Unformatted text preview: VEN 2 Pests and Diseases Grape Diseases • Fungal diseases • Powdery mildew (all green tissue) • Downy Mildew (all green tissue) • Botrytis (can infect green tissue early in year and fruit later on) • Eutypa dieback (wood) Grape Diseases •Bacterial Diseases •Pierces Disease (xylem limited) •Viral Diseases •Fanleaf degeneration •Leaf roll (phloem limited) Powdery mildew, Powdery Uncinula necator Uncinula Photo by Jack Kelly Clark Powdery mildew on fruit fruit Photo by Jack Kelly Clark Powdery mildew on Thompson Seedless grapes Thompson Photo by Jack Kelly Clark Botrytis-blighted flower cluster Botrytis Botrytisinfected berry Photo by William J. Moller Photo by Jack Kelly Clark Botrytis bunch rot, Botrytis cinerea Botrytis Lesion at Lesion node of young shoot shoot Photo by William J. Moller. Photo by Jack Kelly Clark Vine affected by Eutypa dieback Eutypa Photo by William J. Moller Wedge-shaped, darkened cankers develop in the vascular tissue develop Photo by William J. Moller Pierce's Disease Disease Symptoms Photo by Jack Kelly Clark Progression of foliar symptoms for a white grape variety with Pierce's disease Pierce's Photo by Jack Kelly Clark Autumn foliar symptoms of Pierce's disease in a red fruit variety disease Blue-green sharpshooter PD is vectored by sharpshooters Green sharpshooter Red-headed sharpshooter Glassy-winged Sharpshooter Leafhopper Nepovirus: “Nematode Transmitted Polyhedral Virus” - GFLVLeaf deformation ‘Fanleaf’ Healthy Fanleaf - GFLV Yellow mosaic symptoms - GFLV Vein banding symptoms - GFLVFruit Symptoms Healthy Affected DAGGER NEMATODE Xiphinema index (female) – a fanleaf virus vector LEAFROLL VIRUSES LEAFROLL Symptoms on Red-Fruited Grapes Red leaves in fall “Rolled under” leaves Reduced vigor Leafroll symptoms on White Fruited Grape: Leaf curling Chlorosis Reduced vigor LEAFROLL FRUIT SYMPTOMS Delayed fruit maturity Poor Color Reduced yield Common mealybug species in CA vineyards Obscure mealybug Grape mealybug Longtailed mealybug Vine mealybug Grape, Obscure & Longtailed MB Damage Vine mealybug damage is more severe. Vine mealybug feeding and honeydew excretion forms “sugar” cones. Simplified Life Cycle of Insects Nymph (Feeding stage) (Winged & Reproductive) Egg Larvae (Feeding stage) Adult → Pupa Within the feeding portion of the life cycle there are specific steps in the growth of the insect called ‘instars’. The exoskeleton is shed and growth continues. Seasonal population dynamics of Insects • Brood = All individuals that hatch at about the same time from eggs laid by one series of parents and normally mature about the same time • Generation = From any given stage in life cycle to the same stage in the offspring • Insects are poikilotherms = cold blooded • Life cycle length depends on temperature • The number of broods or generations at a given location will differ due to the temperature at that location Leafhoppers Leafhoppers Erythroneura elgantula Erythroneura and and Erythroneura variablis Grape Leafhopper Variegated Leafhopper Leaf stippling caused by hopper feeding. Leaves will turn brown and vines can be defoliated at high populations. Adult egg parasite of the leafhopper, a tiny wasp. Parasitized grape leafhopper egg. The small red dot in egg is the parasite’s egg. WESTERN GRAPELEAF SKELETONIZER SKELETONIZER Harrisina brillians Mating male and female moths of the western grapeleaf skeletonizer western Photo by Jack Kelly Clark Fourth-instar larvae of the western grapeleaf skeletonizer feeding on a grape leaf grape Close-up of the head of a WGLS larva showing its poisonous, stinging hairs Pale, scraped surface of a grape leaf fed upon by larvae of western grapeleaf skeletonizer grapeleaf Brown leaves and sparse canopy of Brown a grapevine fed upon by larvae of western grapeleaf skeletonizer western Photo by Jack Kelly Clark Omnivorous Leafroller Omnivorous Platynota stultana adult female moth on a grape Omnivorous leafroller Omnivorous Photo by Jack Kelly Clark Larva of the omnivorous leafroller folding a leaf by tying edges together with silk threads with Photo by Jack Kelly Clark Silken nests made by larvae of the omnivorous leafroller and their feeding damage on developing grape flowers damage Photo by Jack Kelly Clark The larva of an omnivorous leafroller in its silken webbing nest on young grape berries young Photo by Jack Kelly Clark Larva of omnivorous leafroller overwintering in a grape cluster mummy in Photo by Jack Kelly Clark Omnivorous Omnivorous Leafroller Damage Damage Rotting and raisining (drying up) of Thompson seedless grapes following chewing damage by larvae of the omnivorous leafroller omnivorous Orange Tortrix Orange Argyrotaenia citrana Orange Tortrix adults and Orange Tortrix an egg mass An orange tortrix larva An Photo by Jack Kelly Clark Spider mites Spider Tetranychus pacificus and Eotetranychus willamettei Willamette mite (left) Pacific mite (right) Mite damage Leaf burning (left) Pinot noir leaf damage (right) Predaceous mite feeding on a Willamette mite (right) Sixspotted thrips is also a predator of both mite species (left) Nematodes Nematodes Meloidogyne spp. (root knot) and Xiphinema index (dagger) Xiphinema (dagger) Courses in Viticulture • VEN 2 – Introduction to Viticulture☺ • • • • • • • • VEN 101A, 101B, 101C – Viticulture Practices VEN 110 – Grapevine Physiology VEN 111 – World Viticulture VEN 115 – Raisin and Table Grape Prod. VEN 116 – Wine Grape Production VEN 118 – Grapevine Pests & Diseases VEN 210 – Grape development & composition VEN 216 – Vineyard establishment ...
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