1. Pests of Grapes

2. Omnivorous leafroller

3. Crop: Grapes, citrus, stone fruit, apples, peppers, kiwi, cotton
Scientific name: Platynota stultana
Order: Lepidoptera
Family: Tortricidae
Range: Southern half of US
Mouthparts: chewing

4. Distinguishing Characters: adult bell shaped with blackish grey snout-like mouthparts that protrude forward from the head. Forewings are dark rusty brown with tan tips. Size varies from 9.5 to 13 (0.38 to 0.5”) long

5. larvae have either a black or brown head capsule

6. Translucent so dorsal vessel can be seen

7. Mature larvae range in color from cream to brownish green with two whitish slightly convex and oblong tubercles on the top of body segment. Omnivorous Leaf Roller (OLR) larvae usually drop to the ground on a thread when disturbed

8. Alternate Hosts: numerous weeds
Oviposition Site: on leaves
Number of generations/year: 4 to 5
Overwintering Stage: in the larval stage in grape mummies, vineyard weeds, and other trash in the vineyard
Damaging stages: larvae

9. Shingle like egg mass of OLR

10. Larva overwintering in a grape berry mummy on bark

11. Typical damage: After about 5 days the eggs hatch, larvae tie two young leaves together to form a nest in which they feed - note they fold leaf, not roll it

12. grape leaffolder, Desmia funeralis rolls grape leaves

13. Later nests appear in flowers

14. In bunches

15. And on shoot tips

16. primary damage is that it allows rot organisms to enter fruit at the sites where it feeds

17. Non Chemical control measures:
Biological control – has more than 10 parasitoids, but they don’t cause much mortality (<10%)
Cultural control – important – plow and disk to bury overwintering larvae. Early harvest to prevent late season damage. Remove trash, mummies and remaining grape bunches.

18. Chemical Control Measures:
Cryolite, Bt, Methomyl – remove basal leaves to increase coverage
Current Pest Status: can be serious pest on North Coast and Central Valley, especially if cultural controls are relaxed

19. Variegated Leafhopper

20. Crop: grapes
Scientific name: Erythroneura variabilis
Order: Hemiptera
Family: Cicadellidae
Range: Southern CA, Central valley as far north as S.J. Co (grape leafhopper is a major pest north of the Tehachapi Mountains, especially in the San Joaquin, Sacramento, and North Coast valleys)
Mouthparts: piercing sucking

21. Distinguishing Characters: adults are distinctly mottled brown, green, and white with a reddish tinge.

22. Eggs are laid under leaf surface in epidermal tissue

23. Egg laid in leaf tissue

24. First instar nymph - The nymphs are almost transparent when first emerged, becoming orange brown to yellow brown

25. Third instar nymph

26. Fifth instar nymph

27. Alternate Hosts: Virginia creeper, apple
Oviposition Site: in epidermal tissue on the underside of the leaves
Number of generations/year: 4-5
Overwintering Stage: adults
Damaging stages: Adults and nymphs

28. Typical damage: remove contents of leaf cells causing stippling, and even leaf drop. Reduces photosynthesis.

29. Can cause honeydew spotting

30. Late season “burn” – high populations cause problem for field workers at harvest

31. Non Chemical control measures:
Biological control – Anagrus parasite is not as effective as it is on grape leafhopper because egg is laid deeper under leaf tissue
Cultural control – Remove weeds in vineyards and surrounding areas before vines start to grow in spring
Removing basal leaves during berry set and the 2- week period following (before adult leafhoppers emerge) will normally reduce peak leafhopper populations during the season by 30 to 50%

32. Chemical Control Measures:
Imidacloprid (Admire), Naled (dibrom)
Current Pest Status: a major pest of grapes in southern California and in the Central Valley as far north as San Joaquin County – under better control in last yrs.

33. Vine Mealybug

34. Crop: Grapes
Scientific name: Planococcus ficus
Order: Hemiptera
Family: Pseudococcidae
Range: Coachella Valley and Kern and Fresno Co in the San Joaquin Valley
Mouthparts: piercing sucking

35. Adults and crawlers
Distinguishing Characters: soft, oval, flat, distinctly segmented, and covered with a white, mealy wax that extends into spines (filaments along the body margin and the posterior end). Has a pinkish body that is visible through the powdery wax

36. Crawlers on an adult female

37. Adult female grape mealybug, Pseudococcus maritim
Nymph of obscure mealybug, Pseudococcus viburni
Adult female longtailed mealybug, Pseudococcus longispinus

38. Alternate Hosts: fig, date palm, apple, avocado, citrus, and a few ornamentals
Oviposition Site: wherever female is (on woody tissue)
Number of generations/year: 4-5
Overwintering Stage: mostly mated females under the bark, within developing buds, and on roots
Damaging stages: adults and nymphs
Typical damage: produce honeydew that drops on the bunches - sooty mold. The mealybug itself will be found infesting bunches. Like the other mealybugs, vine mealybug can transmit grape viruses

39. Non Chemical control measures:
Biological control – Anagyrus pseudococci has been released – up to 90% parasitism in some places on central valley. More effective in later generations (August and September)
Cultural control – female mealybug is unable to fly so it must be carried by humans, equipment, birds, or on vines at the time of planting. Do not allow contaminated equipment, vines, or grapes near uncontaminated vineyards
Mating disruption?

40. Chemical Control Measures:
bloom time application of imidacloprid. The following year, treat with chlorpyrifos and oil in the delayed dormant period
Current Pest Status: limited distribution, expected to become a major pest

41. Western Grapeleaf Skeletonizer

42. Crop: grapes
Scientific name: Harrisina brillians
Order: Lepidoptera
Family: Zygaenidae
Range: Central CA to Mexico
Mouthparts: chewing

43. Distinguishing Characters: adults are metallic bluish or greenish black and fly during the day. Body length is about 15 mm (0.6 inch) and the wing span is mm (1 to 1.3 inches)

44. Whitish capsule shaped eggs

45. Eggs are laid in clusters on underside of leaves

46. There are five larval stages
There are five larval stages. The first two stages are cream colored, the third stage is brownish

47. Fourth and fifth stages are yellow with two purple and several blackish bands

48. Larvae have conspicuous tufts of long black poisonous spines that cause skin welts on field workers

49. Alternate Hosts: Boston ivy, Virginia creeper
Oviposition Site: in clusters on underside of leaves
Number of generations/year: three generations per year in the Central Valley and two generations in the cooler coastal regions
Overwintering Stage: pupae under bark
Damaging stages: larvae
Typical damage: defoliate vines. When defoliated, larvae will then feed on bunches causing rot. Defoliation can cause sunburn of fruit and reduces quality

50. Damage from early instar larvae

51. Damage from early instar larvae

52. Damage from fourth instar larvae

53. Severe defoliation

54. Non Chemical control measures:
Biological control – two parasitoids have been introduced – one is common in San Joaquin Valley
A granulosis virus has also been introduced in some areas with excellent success
A Tachinid fly parasitoid

55. Symptoms of granulosis infected WGLS:
Eggs scattered and # reduced, many don’t hatch
Larvae feed in patches
Larvae shrink and die

56. Chemical Control Measures:
Bt, Cryolite, Methomyl (Lannate), Carbaryl (Sevin) – good under leaf coverage is required
Current Pest Status: occasional flare-ups in isolated vineyards, but much less of a problem that it was (increasing lately?)

57. Grape Phylloxera

58. Crop: grapes
Scientific name: Daktulosphaira vitifoliae
Order: Hemiptera
Family: Phylloxeridae
Range: wherever Vitis vinifera rootstock is grown. Prefers heavy clay soils that are found in the cooler grape-growing regions of the state such as Napa, Sonoma, Lake, Mendocino, and Monterey counties, as well as the Sacramento Delta and the foothills. Although grape phylloxera is present in the heavier soils of the San Joaquin Valley, damage may not be as severe. It is not a pest on sandy soils.

59. Mouthparts: piercing sucking
Distinguishing Characters: majority of grape phylloxera adults are wingless females. They are generally oval shaped, but egg layers are pear shaped. They are small 1 mm long. .5 mm wide (0.04 x 0.02 “) and vary in color from yellow, yellowish green, olive green, to light brown, brown, or orange. Newly deposited eggs are yellow, oval, and about twice as long as wide.

60. Alternate Hosts: none
Oviposition Site: deposited on roots
Number of generations/year: 3-5
Overwintering Stage: small nymphs on roots
Damaging stages: adults and nymphs
Typical damage: damage the root systems causing swelling of the root – can kill sections of root. May also cause leaf galls. Causes vines to become stunted and produce less fruit.

61. Root heavily infested with grape phylloxera

62. Leaf galls caused by Phylloxera

63. Non Chemical control measures:
Biological control – very little known
Cultural control – use of resistant rootstocks is the key - Avoid rootstocks that have V. vinifera parentage.
In the hot Central Valley, phylloxera damage may be reduced by good water management, fertilization, and other cultural practices that help limit plant stress

64. Chemical Control Measures:
Carbofuran through drip irrigation, Imidacloprid - pesticide treatment will not eradicate phylloxera populations; the chemical cannot easily penetrate the heavy soils that this pest prefers.
Current Pest Status: becoming more of a problem in central valley because of V. vinifera rootstock planted

65. Glassy Winged Sharp Shooter

66. Crop: Grapes, Citrus, Ornamentals
Scientific name: Homalodisca vitripennis
Order: Hemiptera
Family: Cicadellidae (same as leafhoppers)
Range: SO Cal, and half way up San Joaquin Valley (native to SE US – introduced to CA in late 80’s)
Mouthparts: piercing sucking

67. GWSS and blue-green sharpshooter
Distinguishing Characters: large head, bulging eyes, shiny (glassy) wings, adult approx. 12 mm (½ inch) long (big for a sharpshooter), abdomen is whitish or yellow,

68. Whitish abdomen

69. Head has numerous ivory to yellowish spots

71. Identification

73. Alternate Hosts: numerous ornamentals
Oviposition Site: in mass of under epidermis of leaf, usually on underside
Number of generations/year: 2
Overwintering Stage: adult
Damaging stages: nymph and adult
Typical damage: suck large amount of plant sap, lower vigor of plant. Main problem is it vectors bacteria that causes Pierce’s Disease – on grapes, oleander leaf scorch on oleander, almond leaf scorch

74. Pierce’s disease on grapes

75. Xylella fastidiosa in the xylem of Chardonnay

76. Chalky, white sharpshooter rain (excrement) residue on lemon

77. Non Chemical control measures:
Biological control – egg parasitoids, one native, one being introduced
Cultural control – quarantine on movement of materials from south to north CA

78. Chemical Control Measures:
Imidacloprid (admire) is main method of control now – eradication strategy in Fresno Co – mainly for reducing chance of vectoring Pierce’s disease
Current Pest Status: a serious concern if it spreads to Napa and Sonoma