Grape Leafroll Virus & Pierce’s Disease Vector Suppression have become Important Components of Vineyard IPM Dan Horton, UGA, Entomology, Athens, GA

Grape Leafroll Virus (GLRV) is the most a recent insect-vectored disease to threaten to vineyard health in the SE, however GLRV is not an endemic disease, that is virus-infected wild grapes are not common and the most competent mealybug vector, vine mealybug is not yet present

Monitor for Mealybugs Under Bark in Dormant Season Incorporate examination of vines for mealybugs and/or honeydew into your routine vineyard management practice If mealybugs are found/suspected take samples and get them to your County Agent Treat with either foliar applications or soil-applied neonicotinoids: Venom/Scorpion, Clutch, imidacloprid, … Applaud Movento chlorpyrifos, diazinon best with dormant oils

Grape Leafroll Virus work to avoid inadvertently introducing the virus, virus-indexed vines may be of help Recognize that PD/leaf-hopper suppression programs will tend to increase the abundance of previously uncommon, then insignificant, phloem-feeding pests such as mealybugs and soft scales Mealybugs & soft scale will overwinter in vineyards, implement delayed dormant/bud swell horticultural oil programs to suppress MBs, soft scale, armored scale and mites, adding chlorpyrifos is good As-needed new shoot treatments: Applaud, Venom, Assail, imidacloprid, Movento …

Pseudococcus (P. longispinus, P. viburni or P. maritimus) would most likely be North GA’s key Leaf roll Virus Vectors (Greg Hodges, UFL, DPI) Grape Mealybug Pseudococcus maritimus Longtailed Mealybug Pseudococcus longispinus

Obscure Mealybug Pseudococcus obscurus Vine Mealybug *** Pseudococcus ficus

GenusspeciesValidation Source AntoninagraminisHendriKo1999 AntoninapretiosaHendriKo1999 AntoninoidesnortoniHendriKo1999 CrisicoccustaxodiiKoszta1996 DysmicoccusboninsisFerris1950bFerris1950b, BenDov1994BenDov1994 DysmicoccusmilleriKoszta1996 DysmicoccusmorrisoniMillerMc1973MillerMc1973, BenDov1994BenDov1994 DysmicoccusobesusThompsCo1990ThompsCo1990, BenDov1994BenDov1994 FerrisiagilliGullanDoSt2003 OracellaacutaKoszta1996Koszta1996, ClarkeNeDe1992ClarkeNeDe1992 ParadoxococcusmcdanieliKoszta1996 PlanococcusficusEzzatMc1956 PseudantoninagiganticoxaHendriKo1999

GenusspeciesValidation Source PseudococcusbryberiaGimpelMi1996 PseudococcuscomstockiMcKenz1967McKenz1967, BenDov1994BenDov1994 PseudococcusmaritimusGimpelMi1996 PseudococcussorghiellusMcKenz1967McKenz1967, BenDov1994, GimpelMi1996BenDov1994GimpelMi1996 PseudococcusspanoceraGimpelMi1996 PseudococcusviburniGimpelMi1996 RhizoecusfloridanusHamble1973Hamble1973, BenDov1994, Koszta1996BenDov1994Koszta1996 RhizoecusspinipesHamble1976Hamble1976, BenDov1994BenDov1994 StemmatomerinxadenticulataHowellMi1976HowellMi1976, BenDov1994BenDov1994 StemmatomerinxaristidaHowellMi1976HowellMi1976, BenDov1994BenDov1994 StemmatomerinxbeshearaeHowellMi1976HowellMi1976, BenDov1994BenDov1994 TrionymuscaricisMillerMc1973MillerMc1973, BenDov1994BenDov1994

LH Suppression has Slowed the Spread of PD in CA Vector Suppression is More Complicated in the Verdant, but Droughty Southeast Soil-Applied Neonicotinoids: imidacloprid (Admire, Alias, other generics) or Venom/Scorpion can either languish if too dry or suffer reduced residual if too wet, wait until as late in the initial growth flush as rain patterns suggest Suggest LH Trapping as the Triggered for Foliar Applications, they are responsive, targeted and they complement neonicotinoids Foliar Treatments Should Alternate Applications of Pyrethroids-- cyfluthrin (Baythroid XL 1EC, Brigade/Fanfare/Tundra with 14-day Intervals

P Pierces Disease and Leafhoppers are Endemic & Present on both Wild & Cultivated Grapes Across the Southeast Pierce’s Disease Management should be an on-going effort to minimize leafhopper abundance to slow PD infection

Leaf hopper abundance in N GA is typically low during the Spring vegetative growth flush, insecticidal suppression of leafhoppers should target the on-set of GWSS in vineyard, a foliar pyrethroids/Imidan program is suggested

Neonicotinoids & Pyrethroids are Resistance-Prone & Inclined to Increase the Risk of Mites; Nicotinoids, Pyrethroids & Organophosphates (OP) are Injurious to Pollinators; A Balanced Program is More Likely to Suppress LH & MB Vectors while Avoiding or Delaying Insecticide Resistance

Spotted Wing Drosophila (SWD) was problematic in VA wine grapes in 2012, while grapes are not felt to be a prime host, SWD can successfully attack sound fruit, hence it should be regarded as a threat

Spotted Wing Drosophila (SWD) Trapping should be a standard operating procedure, augmented by frequent fruit examination. SWD should be easily controlled, but if it attacks N GA vineyards it will require an aggressive, scheduled insecticide program.

Japanese Beetles are Significant Foliage Pests, and Modestly Important, Occasional Fruit Pests of Muscadine Grapes Japanese beetle populations get out of hand quickly, especially as soaking, drought-breaking rains prompt heavy, synchronous adult emergence Defoliation from Japanese beetle is more serious as grapes reach veraison, berry ripening, greater than 10% defoliation is probably injurious, but the key to managing Japanese beetles is to act before they become truly numerous

Japanese Beetle Insecticide Options in Muscadine acetamiprid (N) Assail 12-h/7-d ++++ cyfluthrin (P) Baythroid, Tombstone 12-h/3-d ++++ bifenthrin (P) Fanfare, Tundra 12-h/30-d ++++ carbaryl (C) 12-h/7-d ++++ diazinon (OP) 24-h/28-d +++ dinotefuran (N) Venom 12-h/24-h* ++++ fenpropathrin (P) Danitol 24-h/21-d ++++ imidacloprid (N) Merit, Provado 12-h/DOH ++++ malathion (OP) 12-h/3-d12-h/3-d +++ methomyl (C) 7-d/1 to 14-d +++ phosmet (OP) Imidan 14-d/ 7 to 14-d ++++