What Causes Eggplant Yellows: Learn About Eggplant Tobacco Ringspot Virus


By: Mary Ellen Ellis

Eggplants with tobacco ringspot may turn completely yellow and die, leaving you with no harvest for the season. You can prevent and control this viral disease by managing pests, using resistant varieties, and practicing good garden hygiene.

What Causes Eggplant Yellows?

Tobacco ringspot virus is often called yellows when it infects eggplants. This is because the symptoms include yellowing of the leaves and eventually of the entire plant if the infection is severe.

Although tobacco ringspot virus is named after tobacco, it can affect a lot of different plants that may grow in your vegetable garden, including:

  • Tomatoes
  • Potatoes
  • Cucumbers
  • Peppers
  • Eggplant

The virus is spread by dagger nematodes, but infected seeds and plant debris also contribute to the spread of the disease.

Signs of Eggplant Yellows Disease

Ringspot virus in eggplants is characterized largely by yellowing of the upper leaves. The leaves may also show a whitening color. Over time, as the infection becomes worse, the lower leaves will yellow, and eventually the entire plant will turn yellow and die.

In other plants, the virus causes more of a mottled or mosaic pattern, but eggplant yellows disease is mostly identified by the leaf yellowing.

Managing Eggplant Tobacco Ringspot Virus

This virus and the resulting infection can be very damaging, and not just to your eggplants. It affects several different vegetables, so if you have it in your eggplants, other plants in your garden could be susceptible to the infection. Practices such as getting quality, disease-free seeds or using varieties of eggplant that are resistant to tobacco ringspot virus could help you prevent having the disease in your garden at all.

If you do get the disease, and see signs of yellows in your eggplants, you can do a few things to manage it. Destroy affected plants before they can infect other plants. Also, keep your garden weed free, as there are several weeds that can host the virus.

Taking steps to control nematodes in the soil can also help. This may involve fumigation of the soil to kill the pests. Finally, you can try rotating crops, using those not susceptible to the virus for a few years before growing eggplant again.

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This issue concludes the 2000 series of Kentucky Pest News (KPN) and marks the end of the 25th year of inclusion of disease information in KPN. The major objective has been to provide timely information on anticipated and occurring diseases in Kentucky. Any comments (favorable or critical) readers may have regarding KPN (i.e., format, subject matter, coverage, timeliness, etc.) may be directed to KPN authors: John Hartman, William Nesmith, Don Hershman, and Paul Vincelli, Extension Plant Pathologists Paul Bachi and Julie Beale, Plant Diagnosticians. The above authors appreciate the efforts of colleagues who have co- authored topics in KPN and Pat Yancey for typing, proofreading, and transmitting KPN.

The final issue of KPN 2000, like final issues of previous years, contains an index of all plant disease topics covered during the current year. The index is alphabetized according to each crop or other subject matter. After each crop, each disease that was discussed the past year is listed with the appropriate issue number(s). KPN issue numbers in parenthesis () refers to a listing of the crop or disease in the "Diagnostic Lab Highlights" section. We wish each of our readers a Cheerful Holiday and Peace and Prosperity in 2001. (Hartman, Nesmith, Hershman, Vincelli, Bachi, Beale, and Yancey).

Cercospora leaf spot - (898)
Cold/frost injury - 881
Disease considerations relating to spring planting of alfalfa - 871
Fusarium crown rot - (887)
Lepto leaf spot - 886, (887), (899)
Pythium root rot - 886
Rhizoctonia stem canker - (893), (898)
Sclerotinia crown rot - (878)
In alfalfa seeded last year - 878
Results from Adair County - 890
Spring black stem of alfalfa - 881
Stemphylium leaf spot - 891
Very active powdery mildew in red clover in southern Kentucky - 882

Corn - Certain ear and stalk rots showing up - 893
Diplodia ear rot - (893), 897
Disease update - 888
Fusarium ear rot - (898)
Gray leaf spot - (889), (893), (894), (895), (898)
Guidelines for planting corn hybrids with gray leaf spot resistance - 873
Maize chlorotic dwarf virus - (890)
Maize dwarf mosaic virus - (890)
Nutritional problems - (888)
Fertilizer burn - (887)
Manganese toxicity - (887)
Zinc deficiency symptoms - (884), (886), (887)
Pollination problems - (895)
Pythium root rot - (886), (887)
Registration of quadris - (901)
Rust - (888), (890), (891), (893), (894)
Smut - (888)
Southern leaf blight - (894)
Stalk rots - Stenocarpella stalk rot - (899)
Gibberella stalk rot - (898), (901)
Severe lodging of lower stalks in fields - (897)
Stalk rots and BT corn - (900)
Widespread stalk rot problems means producers should scout now - (898)
Stewart's wilt - (884)
Stinkbug injury - (888)
Virus complex - (898)
Sorghum - Maize dwarf mosaic - (894)
Virus epidemics in sweet sorghum - 894

FLOWERING ANNUALS AND PERENNIALS, GREENHOUSE ORNAMENTALS, HOUSEPLANTS, AND GROUND COVERS

Begonia - Bacterial spot - (890), (894)
Botrytis blight - (878)
Spider mites and botrytis blight - (877)
Chrysanthemum - Bacterial leaf spot - (897)
Botrytis blight - (896)
Pythium root rot - (888), (893), (894)
Rhizoctonia root rot - (891)
Daylily - Pythium - (898)
Rhizoctonia root rot - (898)
Delphinium - Fusarium stem rot - (889)
Epimedium - Bacterial spot - (894)
Fuchsia - Growth regulator damage - (877)
Geranium - Bacterial blight - (894), (895)
Pseudomonas leaf spot - (892)
Pythium root rot - (882)
Greenhouse floral crops - Gray mold and powdery mildew -(902)
Heuchera - Bacterial spot - (898)
Hibiscus - Cercospora leaf spot - (901)
Hollyhock - Rust - (880)
Hosta - Southern stem blight - (889)
Impatiens - Bacterial spot - (896), (897)
Ethylene exposure - (873)
Excessively high soluble salts - (873)
Necrotic spot virus - (881)
Rhizoctonia root and stem rot - (887), (888), (891), (892), (894), (897), (898)
Iris - Bacterial soft rot - (881)
Heterosporium leaf spot - (884), (889)
Leaf spot - (880), (883)
Ivy - Bacterial spot - (874), (879), (889), (891), (894)
Jack-in-the-pulpit - Rust - (884)
Lavendar - Black root rot - (879)
Lily - Rhizoctonia stem and root rot - (890)
Liriope - Anthracnose - (879)
Marigold - Alternaria leaf spot - (897)
Rhizoctonia stem rot - (888)
Oriental lily - Rhizoctonia stem rot - (887)
Pachysandra - Volutella blight - (897), (899)
Pansy - Black root rot - (897)
High PH - (873)
Pythium root rot - (899)
Peony - Anthracnose - (884)
Botrytis blight - (880)
Cladisporium spot - (884), (898)
Petunia - Black root rot - (892)
Botrytis blight - (878)
Impatiens necrotic spot virus - (881)
Pythium root rot - (897)
Rhizoctonia stem and root rot - (888), (890), (892)
Phlox - Southern stem blight and canker - (890)
Poinsettia - Botrytis blight - (896), (897)
Pythium root rot - (901)
Scab - (897)
Purple coneflower - Fusarium crown rot - (884)
Ranunculus - Downy mildew - (877)
Rose - Botrytis blight - (888)
Black spot - (880), (884), (887), (892)
Phytophthora root rot - (891)
Powdery mildew - (886), (887), (895)
Rose mosaic virus - (877), (884), (887)
Rose rosette - (880), (897), (898)
Rudbeckia - Bacterial leaf spot - (895)
Snapdragon - Rhizoctonia stem rot - (889)
Vinca - Botrytis blight - (892)
Impatiens necrotic spot virus - (898)
Phytophthora - (892)
Rhizoctonia stem rot - (887), (889), (892)
Southern blight - (898)
Viola - Rhizoctonia stem rot - (887)
Yucca - Coniothyrium leaf spot - (879)
Zinnia - Rhizoctonia stem rot - (887)

Apple - Bitter rot - (893)
Cedar apple rust - (884), (890), (893), (894), (895)
Fire blight - (884), (887), (895)
Foliar and stem/vascular problems - (888)
Frogeye leaf spot - (890), (893)
Necrotic leaf blotch - (894)
Powdery mildew - (878)
Scab - (879), (881), (884), (890)
Sooty blotch - (895)
Septoria leaf spot - (893)
Spring frost injury - (894)
Verticillium wilt - (893)
Blackberry - Anthracnose - (881), (891)
Orange Rust - 879, (880), (881)
Tomato ringspot virus - (890)
Cherry - Bacterial canker - (898)
Grape - Anthracnose - (887), (890)
Black rot - (884), (884), (887), (888), (890), (891), (892)
Crown gall - (893), (893)
Cane and leaf spot diseases - (884)
Pre-harvest management of fruit diseases - (891)
Gooseberry - Powdery mildew - (894)
Nectarine - Brown rot - (887)
Oriental fruit moth damage - (887)
Peach leaf curl - (880)
Pear - Fireblight - (894)
Peach - Brown rot - (894), (898)
Peach leaf curl - (879), (880)
Scab - (895), (898)
Pear - Cork spot - (893)
Fire blight - (880), (884)
Plum - Bacterial spot - (895)
Black knot - (874), (881)
Blumeriella leaf spot - (890)
Plum pockets - (883), (884)
Plum pox virus a threat to Kentucky? - (870)
Raspberry - Anthracnose - (898)
Phytophthora root and crown rot - (892)
Strawberry - Anthracnose - (882)
Leaf spot diseases - (886)
Mycosphaerella leaf spot - (887), (888)
Septoria leaf spot - (901)
Disease control with strobilurin fungicides - (882)
How will fruit crop diseases respond to the drought of 1999? - (869)
Obtaining weather data for apple IPM - (873)
Problematic tree fruit summer diseases - (889)
Recent weather influences apple and crabapple diseases - (877)
Winter cultural practices to control tree fruit diseases - (871)

FUNGICIDES AND PESTICIDES

Bayleton 50 receives label for gray leaf spot -( 885)
Fungicidal control of gray leaf spot - (880)
Several fungicides no longer available for home lawn use - (873)

Oats - Barley yellow dwarf virus - (879)
Probable impact of 1999 drought on the future disease potential in grain crops - (869)

LANDSCAPE TREES AND SHRUBS

Azalea - Leaf/flower gall - (883), (886)
Ash - Anthracnose - (881), (883)
Yellows - (894), (898), (899)
Barberry - Powdery mildew - (886)
Verticillium wilt - (887), (891)
Box elder - Phyllosticta leaf spot - (884)
Boxwood - Black root rot - (898)
Phytophthora root rot - (898)
Powdery mildew - (895)
Chestnut - Phytophthora root rot - (891)
Conifers - Drought stress - (873), (874)
In trouble - (894)
Crabapple - Powdery mildew - (877)
Scab - (882), (885), (892)
Crepe myrtle - Powdery mildew - (895)
Dogwood - Anthracnose - (886), (894)
Diseases are appearing - (885)
Powdery mildew - (888), (888), (891), (892), (894), (895)
Spot anthracnose - (880), (884)
Elm - Dutch elm disease - (894)
English laurel - Bacterial spot - (891)
Euonymus - Powdery mildew - (884), (895)
Hawthorn - Cedar-quince rust - (887), (889), (893)
Hemlock - Drought stress - (874)
Honeysuckle - Powdery mildew - (884)
Horsechestnut - Guignardia leaf blotch - (891)
Hydrangea - Cercospora leaf spot - (897)
Inkberry - Black root rot - (878)
Ivy - Leaf spots - 890
Japanese holly - Black root rot - (879)
Junipers - Cedar-apple rust - (877)
Drought stress - (876)
Phomopsis twig blight - (877)
Twig blight - (884)
London plane - Bacterial leaf scorch - (897), (899)
Magnolia - Verticillium wilt - (892)
Maple - Anthracnose - (881), (882), (883), (884), (886), (887)
Bacterial leaf scorch - (899), (901)
Verticillium wilt - (884), (886), (893)
Mulberry - Cercosporella leaf spot - (898)
Nectria canker - (897)
Oak - Antinopelte leaf spot - (901)
Bacterial leaf scorch - (895), (896), (897), (898), (899), (901)
Will injections save oaks - (901)
Hypoxylon canker - (890)
Leaf blister - (884), (891)
Powdery mildew - (901)
Photinia - Entomosporium leaf spot - (880), (888), (901)
Pine - Pine wilt - (876)
Drought stress - (876)
Pine needle scale infestation - (877)
Tip blight - (877), (901)
Pyracantha - Scab - (894)
Redbud - Verticillium wilt - (884), (887), (899)
Rhododendron - Pestalotia invading sun/wind damaged leaves - (877)
Phytophthora crown and root rot - (899)
Sunscald - (876)
Stress-related symptoms - (876)
Smoketree - Verticillium wilt - (894)
Sourwood - Cercospora leaf spot - (898)
Spruce - Cytospora canker - (873), (874)
Drought stress - (876)
Sycamore - Anthracnose - (881)
Viburnum -Bacterial leaf spot - (898)
Vinca - Stem blight - (887)
Walnut - Causing wilt in the garden - (895)
Willow - Botryosphaeria canker - (890)
Crown gall - (894)
Dieback - (890)
Yellowwood - Anthracnose - (893)
A Kentucky conference on tree roots and soil health - (898)
Bacterial leaf scorch is visible now - (898)
Bacterial wetwood and slime flux is different from winter pruning sap flow - (872)
Dead or dying landscape trees - (883)
Disease management using IPM in the home landscape - (875)
How will landscape plant diseases respond to the drought of 1999? - (869)
Landscape plant diseases observed at plant diagnostic workshop - (887)
Landscape plant diseases being seen now - (881)
Landscape plant health care workshops to be held in July and August - (888)
Phytophthora root, crown, and collar rot - (896)
Problem trees and tree problems - how to improve your diagnostic skills - (885)
Stress and herbicide damage on various shrubs and trees in the landscape - (878)
Shade tree anthracnose in the landscape - (876)
Woody landscape plant diseases - (894)

Bermudagrass - Bipolaris leaf blight - (890)
Midsummer cultivation to reduce spring dead spot - (890)
Rhizoctonia crown rot - (886)
Bentgrass - Anthracnose - (892), (895)
Summer patch - (892)
Rhizoctonia - (876)
Bluegrass - Anthracnose - (896)
Brown patch - (891)
Necrotic ringspot - (882), (884)
Old lawns showing various diseases - (878)
Pythium - (891)
Rust - (886), (894), (898)
Summer patch - (889), (898)
Brome grass - Powdery mildew - (880)
Fescue - Anthracnose - (886)
Brown patch - (888), (889), (890), (891), (895), (896)
Leaf spot - (880)
Loose smut - (893)
Rust - (893), (894)
Orchardgrass - Brown stripe - (886), (893)
Leaf streak (Cercosporidium) - (879)
Ryegrass -Anthracnose - (898)
Brown patch - (890)
Gray leaf spot - (895), (898)
Control suggestions given last week are for golf courses - (881)
Cultural practices for minimizing - (876)
Detected on perennial ryegrass - (894)
No reports yet - (893)
Rust - (886), (893)
Sudex - Fusarium root and stem rot - (899)
Turfgrass - Anthracnose - (884)
Diseases active - (891)
Necrotic ringspot - (884)
Pythium root rot - (893)
Recent diseases - (889)
Rhizoctonia root rot - (884)
Slime molds - (889)
Take-all patch - (893)
Yellow patch - (873)
Zoysiagrass - Large patch - (886)
Disease control for renovation and overseeding - (894)
Ergot risk in tall fescue going to seed - (887)
Rust and fairy rings are very noticeable in some lawns - (901)
Slime molds: return of the blob - (885)
Turf field day set for July 13 - (889)
Update on bioject system for biological control of dollar spot - (879)

Diagnostic tips for drought-related problems - (869)
Ginseng - Alternaria blight - (887)
IR-4 program-national program providing pest management solutions for minor-use crops - (900)
Luminescent fungi - (900)
Mulch - Slime molds - (889)
Wild mushrooms - to eat or not to eat - (900)

Pecan - Diseases appearing now - (892)
Scab - (888), (892)
Walnut - Phytophthora root and crown rot - (895)

Anthracnose - (898)
Charcoal rot - (897), (898), (901)
Downy mildew - (897)
Frogeye leaf spot - (897)
Fusarium stem rot - (888), (892), (893), (894)
High bean leaf beetle populations could mean more bean pod mottle this season - (886)
Phytophthora blight - (893)
Potassium deficiency - (895)
Purple seed stain - (901)
Pythium root rot - (889)
Rhizoctonia root and stem rot - (888), (889), (891), (892), (893), (894)
Root knot nematode - (898)
Southern blight - (891)
Soybean cyst nematode - (896), (897), (898)
Infestations often hidden - (890)
Managing in double crop soybean - (888)
Stem canker - (897), (898)
Stem canker or sudden death syndrome? - (893)
Sudden death syndrome - (895), (896), (897), (898), (899)
Explosion - (895)
Update - (896)

Actigard labeling delayed - be careful with demonstration plots - (883)
Aphid borne virus complex - (893), (894), (895), (896)
Alfalfa mosaic virus - (891)
Angular leaf spot - (886), (888), (889), (890), (891), (892)
Bacterial black leg, hollow stalk and soft rot - (878), (886), (894), (895)
Black root rot - (886), (887), (889), (890), (893)
Black shank - (881), (884), (886), (887), (888), (889), (890), (891), (892), (894), (895)
Blue mold - (888), (889), (890), (891), (892), (893), (893), (894), (895)
Brown spot - (891)
Chemical injury - (884)
Cold/frost injury - (881)
Current Blue Mold Status - (875), (877), (878), (880), (881), (883), (884), (886), (888), (890), (891), (892), (895)
Damage from sucker control chemicals - (893)
Dealing with mold on curing tobacco - (898)
Disease control in tobacco transplant production systems - 2000 crop - (873)
Drought of 1999 - (869) Effect of adding terrazole 35 fungicide to the float water on transplant development, pythium control and crop yield of burley tobacco - KY 14 - (879)
Evaluation of ridomil gold and ultra flourish for black shank control in burley tobacco - (874)
Fertilizer burn - (884)
Foliar chemical options labeled for tobacco diseases in the field - 2000 season - (890)
Frogeye - (891), (892)
Fusarium basal stem rot - (887), (889), (891)
Fusarium wilt - (889), (890), (892), (893), (894)
Heat stress - (884)
Herbicide injury - (886)
High alkalinity - (877)
High soluble salts - (877)
Low fertility - (877)
Lightning damage - (895)
Manganese toxicity - (886), (887), (891)
New fungicide for pythium control in tobacco float beds - (879)
Nutritional/chemical problems - (889)
Pythium root rot - (878), (879), (880), (881), (882), (883), (884), (887)
Rhizoctonia damping-off - (878), (880)
Root knot nematode - (890)
Sclerotinia collar and crown rot - (880), (882)
Soreshin - (888), (889), (890), (891), (892), (893), (894)
Target spot - (879), (880), (881), (882), (883), (884), (886), (887), (888), (890), (892), (893), (895)
Temporary phosphorus deficiency - (886)
Tobacco disease control planning should be a priority - (902)
Tobacco problems following this prolonged wet period - (887)
Tobacco ringspot virus - (886)
Tobacco streak virus - (886), (889), (890)
Tomato spotted wilt virus - (886), (887), (889), (890), (891), (892), (894)
Transplant shock - (886)
Tray sanitation - a key step to disease management in float-transplant production systems - (870)
Viruses - (888)

Asparagus - Fusarium crown rot - (880), (882)
Basil - Fusarium stem canker - (882)
Bean - Fusarium stem rots - (887), (888), (889), (892)
Rhizoctonia - (887), (888), (892)
Rust - (894)
Broccoli - Soft rot - (901)
Cabbage - Rhizoctonia - (882), (896), (898)
Cantaloupe -Alternaria leaf blight - (892)
Bacterial wilt - (888), (892), (893)
Fusarium root and stem rot - (889)
Gummy stem blight - (889)
Cucumber - Anthracnose - (891)
Bacterial spot - (891)
Bacterial wilt - (889), (894)
Fusarium wilt - (879)
Rhizoctonia stem rot - (887)
Southern blight - (891)
Cushaw - Fusarium fruit rot - (898)
Eggplant - Early blight - (889)
Kale - Pythium damping-off - (881)
Lettuce - Sclerotinia - (880)
Okra - Stinkbug damage - (897)
Verticillium wilt - (897)
Oregano - Bacterial leaf spot - (890)
Pepper -Alfalfa mosaic virus - (891)
Anthracnose - (896), (897)
Bacterial spot - (888), (889), (890), (893), (895)
Rhizoctonia stem rot - (889)
Potato - Scab - (895), (899)
Pumpkin - Angular leaf spot and virus complex - (893)
Bacterial fruit rot - (899)
Bacterial wilt - (892), (894)
Gummy stem blight - (895)
Microdochium blight - (894)
More attention needed to disease control by Kentucky farmers - (893)
Phytophthora fruit rot - (897), (899)
Powdery mildew - (895), (896)
Virus complex - (895)
Rhubarb - Crown rot (Erwinia) - (879)
Squash - Bacterial fruit rot - (899)
Bacterial wilt - (886), (888), (889)
Phytophthora fruit rot - (899)
Pollination problems - (888)
Watermelon mosaic virus II - (889)
Sweet Corn - Expect Stewart's wilt - (876)
Tomato - Anthracnose - (896)
Aster yellows - (889)
Bacterial canker - (889)
Bacterial pith necrosis - (895)
Bacterial soft rot - (887)
Bacterial speck - (883), (884), (886), (887), (888), (889), (893), (894)
Bacterial spot - (886), (890), (893), (894)
Bacterial wilt - (888), (891)
Blossom end rot - (893)
Buckeye rot - (889)
Cat facing - (892)
Cucumber mosaic - (892)
Early blight - (887), (889), (892), (893), (894), (896)
Ethylene exposure - (873)
Fusarium stem rot - (888)
Fusarium wilt - (887), (888), (891), (893)
Impatiens necrotic spot virus - (881)
Mosaic virus - (874)
Pythium - (876)
Root knot nematode - (889), (894)
Sclerotinia - (883), (884)
Septoria leaf spot/speck - (886), (887), (889), (891), (892)
Southern stem blight - (889), (891)
Sour rot - (897)
Tomato spotted wilt virus - (887), (888), (889), (890), (891), (894)
Walnut wilt - (888)
Watermelon - Alternaria leaf blight - (888)
Black root rot - (888)
Commercial vegetables - (869)
Disease management strategies for tobacco growers turned vegetable growers - (871)
Fungicides are especially important to fall vegetable production - (896)
Get diseases and disorders of commercial vegetable crops diagnosed - (882)
Home garden disease management - (880)
Nova labeled on cucurbits for powdery mildew control - (890)

Barley yellow dwarf - (880), (882), (884)
Changed wheat foliar fungicide picture for 2000 season - (871)
Cold/frost injury - (881)
Correction - (872)
Disease update - (883)
Environmental and nutritional problems - (874), (876)
Fusarium head blight (head scab) in relation to tillage and previous crop - (899)
Glume blotch - (886)
Leaf blotch - (883)
Powdery mildew - (874), (880), (882), (884)
Got Mildew? - 876 Management: now is the time for decision-making - (898)
Soilborne mosaic virus - (881)
Spindle streak mosaic virus - (876), (880), (881), (882), (883), (884)
Take-all - (881), (883), (884), (885)
Wheat streak mosaic virus - (878), (879), (880), (881), (882), (883), (884)
Epidemic - (879)
Disease considerations following destruction of wheat - (880)

ENTOMOLOGY

Spray drift - 874
Tips - 874

GARDEN AND FIELD CROP PESTS

Alfalfa pests - 871, 873, 885, 888, 894, 895, 897
Alfalfa weevil - 873
Aphids - 874, 877, 887
Armyworm - 881, 882, 883
Bean leaf beetle - 884, 886
Bees - 891
Blister beetle - 894
Brown stink bug - 886
Bt Corn - 870, 879, 886, 890, 898, 900
Budworm - 887
Bumble bees - 891
Burrower bugs - 885, 887
Corn flea beetles - 874
Corn earworms - 896, 896
Corn pests - 873, 874, 879, 882, 883, 885, 886, 887, 888, 890, 891, 893, 894, 896, 897, 898, 899, 900
Corn rootworm - 883
Crickets - 895
Crop rotation - 899
Cutworms - 877, 879, 882
European corn borer - 882, 886, 887, 888, 890, 891, 894, 897, 898
Fall armyworm - 890, 895
Flea beetle - 874, 877, 879
Fulfill (pymetrozine) - 874
Garden clean-up - 893
Genetically modified crops - 870
Grasshoppers - 887, 888, 889 895
Green clover worm - 889
Hornets - 891
Hornworm - 887, 888
Japanese beetle - 889, 890, 892
Mealworms - 885
Mealworm beetles - 885
Mexican bean beetle - 895
Millipedes - 872
Northern corn rootworms - 899
One-spotted stink bug -
Paper wasps -891
Pill bugs - 872
Potato leafhoppers - 871, 885, 888
Shore flies - 876
Slugs - 872, 887
Sorghum midge - 889
Southern corn rootworm beetle - 895
Southwestern corn borer - 873, 886, 888, 890, 893, 894, 897, 898
Soybean aphids - 900
Soybean pests - 882, 884, 885, 886, 887, 889, 896, 900
Soybean podworm - 896
Spined Soldier bug - 886
Spotted cucumber beetle - 895
Stalk borers - 887
StarLink - 898, 899
Stink bug - 888
Three cornered alfalfa hopper - 897
Tobacco aphids - 888, 890, 892
Tobacco Budworm - 887
Tobacco pesticides - 874
Tobacco pests - 872, 876, 877, 881, 882, 887, 888, 890, 891, 892
Tomato hornworms - 890
Wasps - 891
Western corn rootworm - 899
Wheat curl mite - 878
Wheat pests - 869, 873, 878, 880, 885
Wheat storage - 885
Winter grain mites - 869, 873, 8870
Wireworms - 877
Yellowjackets - 891
Yellow striped armyworm - 887

Apple maggot flies - 891
Apple pesticides - 874
Chestnut weevils - 892
Codling moth - 874, 878, 885, 901
Danitol 2.4 EC - 874
IPM - 878
Nut weevil - 892
Pecan weevil - 892
San Jose scale - 877, 901
Pheromone traps - 877
Rednecked cane borer - 884

Asian lady beetles - 900
Red imported fire ants - 900

Ants - 892
Asian lady beetle - 899
Boxelder bugs - 872
Carpenter ants - 883
Carpenter bees - 878
Carpet beetles - 901
Clothes moth - 901
Clover mites - 884
Crickets - 895
Dursban - 886
Dust mites - 869
Foreign grain beetle - 891
Fruit flies - 895
Head lice - 870
Lice - 870
Mites - 884
Mosquitoes - 889
Pest-proof your home - 898
Termites - 876, 880
Yellowjackets - 897

HUMAN, PUBLIC HEALTH PESTS

Chiggers - 882
Lone star tick - 896
Ticks - 882, 896

In schools - 875
Apple - 878

Bees - 875
Cicada killer wasps - 890
Clover mite - 872, 877
Earthworm - 872,
Flies - 896
Galls - 883
Honey bees - 875
Japanese beetles - 887, 895
Maple galls - 883
Masked chafer beetle - 887, 895
Plasterer bee - 875
Snowfleas - 872
Springtails - 872
White grubs - 895
Winter grain mites - 872
Yard bees - 875
Yellowjackets - 896

Bot flies - 900
Cattle lice - 872
Cattle grubs - 872, 892
Common cattle grub - 892
Deer flies - 883
Ear tags - 881
Face fly - 881
Fly control - 883
Horn fly - 881
Horse bots - 900
Horse flies - 883
House flies - 883
Lice - 872
Northern cattle grub - 892
Northern fowl mite - 881
Stable flies - 883

Bagworm - 883, 884
Black caterpillars - 894
Boxelder bugs - 898
Bronze birch borer - 884
Calico scales - 878
Cecropia moth caterpillar - 894
Dogwood borer - 884
Eastern tent caterpillar - 879
Flatheaded appletree borer - 884
Galls - 883
Hickory horned devil - 894
Hickory tussock moth - 894
Honey locust borer - 884
Honey locust plant bugs - 879
Hawthorn lace bug - 879
Leatherwings - 897
Lilac borer/Lesser peachtree borer - 879
May beetles - 881
Oak galls - 883
Oakworms - 894
Oystershell scale - 879
Saddletack caterpillar - 894
Slugs - 878
Soldier beetles - 897
Stinging rose caterpillar - 894
Vein pocket gall - 883
Wheel bugs - 895
White grubs - 881
Yellow-necked caterpillars - 894

Southern pine beetles - 873

Colorado potato beetle - 884, 887
Corn flea beetles - 877
Cucumber beetle - 887, 892
Cutworms - 877
Diamondback moth - 877
Earwigs - 885
European corn borer - 892
Fall armyworm - 892
Flea beetle - 877
Imported cabbageworm - 877
Mites - 891
Sanitation - 893
Southwestern corn borer - 892
Squash vine borer - 885
Two-spotted spider mite - 891

Acephate - 873
Applicator law - 899
BT corn - 898
Consumer labeling initiative - 875
Danitol 2.4 EC = 874
Disyston - 871
Dursban - 886, 887
Fulfill - 874
IPM in schools - 875
IR-4 Program - 900
Labels - 875
Methamidophos - 873
Monitor - 871
Orthene - 871
Organophosphate insecticides - 873
Pesticide labels on the web - 871
StarLink - 898


Oregon’s Most Unwanted: Invasive Species

Symptoms of Plum Pox Virus on peach fruit including rings and blotches of uneven color. Courtesy Ontario Ministry of Agriculture, Food and Rural Affairs. © Queen's Printer for Ontario, 2010. Reproduced with permission.

Invasive species are those plants, animals, and microbes not native to a region which, when introduced either accidentally or intentionally, out-compete native species for available resources, reproduce prolifically, and dominate regions and ecosystems. Because they often arrive in new areas unaccompanied by their native predators, invasive species can be difficult to control. Left unchecked, many of these organisms have the potential to transform entire ecosystems, as native species and those that depend on them for food, shelter, and habitat disappear.

The Oregon Invasive Species Council has developed a list of the 100 least wanted species. These organisms threaten to invade at any time and available information allows us to predict that they would have a serious negative economic or ecological impact if they were to become established in the state. Eradication should be seriously considered if incipient populations are found. The costs of eradication are likely to be much less than the impacts associated with permanent establishment. This list is updated annually. If you suspect you have seen one of the 100 least wanted species, call the Invasive Species Hotline, 1-800-INVADER (1-800-468-2337).

The list is made up of micro-organisms, aquatic plants, land plants, aquatic invertebrates, land invertebrates, fish, birds and mammals. Only the plant parasitic ones are listed below:

Fungi and Fungal-like Organisms

Alder root rot — Phytophthora alni – In 1993 a new collar-rot disease of European alders ( Alnus spp.) was reported in the U.K. A Phytophthora was isolated and shown to comprise a swarm of hybrids between two Phytophthora species: P. cambivora and a Phytophthora close to P. fragariae . Both these ‘parent’ species were probably introduced into Europe. Neither is a pathogen of alder i.e., the hybridization event may have led to a new host specificity. The event is probably recent and it has been suggested that it occurred in a nursery environment. The hybrids are now spreading across Europe, probably mainly via infested planting stock. A few samples from south-central and interior Alaska were positive for this fungus in 2008.

Chalara dieback of ash — Chalara fraxinea ( Hymenoscyphus pseudoalbidus ) – A recently described fungus killing ash trees, this disease has spread quickly across Europe and was reported for the first time in Great Britain in 2012. Fraxinus excelsior , F. angustifolia , F. mandschurica , F. nigra , F. pennsylvanica , and F. Americana are all reportedly susceptible to the disease the susceptibility of Oregon’s native ash, F. latifolia , is unknown. Although the life cycle of the fungus is poorly understood, ascospores are forcibly discharged and then wind-dispersed, allowing for rapid spread. Symptoms initially appear as small necrotic spots on leaves, petioles, or rachises. Lesions enlarge expanding along petioles and rachises into stem tissue. Young trees are most vulnerable to rapid death, whereas older trees may take years to die. Other symptoms include leaf necrosis, wilting, premature shedding, cankers on shoots and main stems, and branch dieback. There are no known treatments once a tree becomes infected, although anecdotal evidence suggests some individual trees may be resistant.

Oak wilt — Ceratocystis fagacearum – Oak wilt has been found in 21 States in the central part of North America. Oak wilt has also been reported in Texas and New York—outside its main range. It was first recognized as an important disease in 1944 in Wisconsin where over half the oaks have been killed. In West Virginia where predominately oak forests cover 70% of the land area, oak wilt losses average less than one tree per square mile each year. No species of oak is known to be immune to this vascular disease. Plantation-grown Chinese chestnuts can also be naturally infected by the oak wilt fungus. Moreover, inoculation experiments have demonstrated that over 35 native and exotic oaks are susceptible, as well as American and European chestnuts, species of chinkapin, tanoak, and several varieties of apple.

Potato wart — Synchytrium endobioticum – A soilborne fungal parasite which is an obligate parasite of certain members of the order Solanaceae with potato ( Solanum tuberosum ) being the only cultivated host. In Mexico some wild Solanum species are also known as hosts. Has been found in Asia (Bhutan, China, India, Lebanon, Nepal), Africa (Algeria, South Africa, Tunisia), Europe (All countries, except Portugal where it was eradicated), North America (Canada [NFLD], USA [eradicated], Mexico), Pacific (New Zealand’s south island), and South America (Bolivia, Chile, Falkland Is., Peru, Uruguay). On October 24, 2000, the Canadian Food Inspection Agency (CFIA) confirmed the presence of potato wart disease in a single field in Prince Edward Island (P.E.I.) and took immediate steps to prevent its spread. This was the first occurrence of potato wart in an agricultural area outside of Newfoundland and Labrador, where a plant quarantine has been in place since 1912.

Disease not yet named — Phytophthora kernoviae – A fungus-like organism found only in the United Kingdom, Ireland, and New Zealand infecting Fagus sylvatica (beech), Rhododendron spp., Quercus robur (English oak), Quercus ilex (holm Oak), Gevuina avellana (Chilean hazelnut), Liriodendron tulipfera (tulip tree), Magnolia stellata , Michelia doltsopa , Pieris formosa and Vaccinium myrtillus . The pathogen was discovered during surveys for P. ramorum and causes similar symptoms on these hosts. It has been found in both nurseries and landscapes. The United Kingdom has an active eradication program in place that includes removal and destruction of entire infected plants including their root balls.

Ramorum canker and blight (Sudden Oak Death) — Phytophthora ramorum – A fungus-like organism that infects over 60 plant genera and 100 plant species, killing hosts such as tanoak ( Notholithocarpus densiflorus ) and Japanese larch ( Larix kaempferi ), and injuring others such as rhododendron ( Rhododendron species). This pathogen is subject to state and federal quarantines designed to contain the disease and prevent its further spread. The disease was first reported to cause leaf blight, stem canker, and tip dieback on nursery-grown rhododendrons and viburnums in Germany and the Netherlands in 1993. At about the same time, many tanoaks and oaks ( Quercus sp.) in the San Francisco Bay Area were dying from this same disease. In Oregon, the fungus was found killing tanoak in a few isolated sites just north of Brookings, OR during the summer of 2001. Since the initial discovery, the disease is considered established and Oregon has focused on limiting spread in Curry County through early detection, monitoring, and eradication of symptomatic tanoak trees. Despite these efforts, the quarantine area in Curry County has expanded many times since 2001 from 9 sq. miles to over 500 sq. miles. The rate of disease spread increased most dramatically in 2014 requiring the quarantine area to nearly double in 2015.

In the spring of 2003, the disease was discovered in a wholesale nursery in Oregon on Pieris , Viburnum , and Rhododendron and in Washington at a retail outlet affiliated with the Oregon nursery. These and nearby host plants were destroyed. An international shipment of rhododendrons was suspected as the source of contamination for these nurseries. The disease has since been detected in nurseries in California, Oregon, Washington, and other several other states. A federal certification program for nurseries has been in place since 2004 to prevent disease spread through infected nursery stock.

The disease was also discovered in a botanical garden landscape on the north end of Bainbridge Island, WA in 2015. Several plants including were infected with the NA-1 clone including Camellia, Gaultheria, Mahonia, Pieris, Rhododendron, Vaccinium, Viburnum and Vinca. Although eradication was completed it is suspected that the pathogen will persist and efforts are focused on containment.

Bacteria and Similar Organisms

Annual ryegrass toxicity — Rathayibacter toxicus – This bacterial pathogen found in Australia, South Africa, Japan, and New Zealand infects annual ryegrass and other grasses with the aid of a nematode vector ( Anguina funesta ). The bacterium infects the seed heads, replacing the seed with a hardened yellow gall made up of bacterial cells. The bacterium also produces a toxin that is deadly to livestock, causing a disease known as ryegrass staggers. The best control method is preventing the introduction of this bacterium so Oregon has adopted a state quarantine for this disease.

Bacterial Blight of Grape — Xylophilus ampelinus – This bacterial disease, limited to grapevines, is found primarily in Europe and South Africa with unconfirmed reports from other continents. Status in South Africa is unknown as it does not occur frequently and it is now listed as eradicated from Turkey. Severe infection of susceptible cultivars can lead to serious harvest losses. Natural dispersal is limited to the vineyard and the immediate area. This disease is liable to be carried on infected grapevine planting material. Further spread could lead to severe economic losses especially since no efficient control measures are known. The bacteria attack the vascular system causing shoot blights and cankers and occasionally leaf spots. Symptoms are observed in early spring to June. Initially, linear reddish-brown streaks appear, extending from the base to the shoot tip then, lens-shaped cracks and cankers develop, sometimes as deep as the pith. Shoots subsequently wilt, droop and dry up. In cases of severe infection, a large number of adventitious buds develop, but these quickly die back. Infected shoots are shorter, giving the vine a stunted appearance. Cross-sections of stems will reveal browning of the tissues. Leaves may develop angular, reddish-brown lesions margins or the entire leaf may die. Light-yellow bacterial ooze may be seen on infected leaves when humidity is high. May be confused with Phomopsis cane and leaf spot as well as a few other diseases.

Hazelnut bacterial canker — Pseudomonas avellanae ( P. syringae pv. coryi ) – The bacterium causes a hazelnut decline and is currently present in about 1,000 out of the 20,000 hectares of hazelnut orchards in central Italy. It has also been found in northern Greece. The main symptoms include the rapid wilting of twigs, branches and trees during spring and/or summer. Characteristically, the leaves remain attached to the twigs after their withering.

Elm Yellows — Candidatus Phytoplasma ulmi – This disease, also called Elm Phloem Necrosis, is caused by an organism similar to a bacterium called a phytoplasma. This ultra-microscopic pathogen only survives in cells of an infected plant or its insect carriers. The whitebanded leafhopper is one of the known carriers of the EY phytoplasma, but there may be other phloem-feeding insects that are carriers. Leafhoppers pass the phytoplasma into phloem cells while they feed, and soon after, all of the phloem in a tree is infected and dies. The tree responds outwardly by wilting, often within one growing season. It occurs in the eastern half of the US and in southern Ontario, erupting in localized epidemics.

Poplar canker — Xanthomonas populi – Only Populus species are affected. It occurs mainly in Europe but reports from Asia are doubtful. Found naturally in wild Populus tremula , but is more damaging to hybrids of Populus canadensis . Other highly susceptible species include Populus trichocarpa, Populus deltoides and Populus tremuloides , which are commonly used in European poplar breeding programs. Infections in young stems spread throughout the cortical tissue, eventually causing the tissue to split open. These cankers may produce bacterial slime in the fall. The bacterium is also capable of taking advantage of tunnels created by larvae of the cambial miner, Phytobia carbonaria , and spreads through these to form elongated cankers.

Willow watermark disease — Brenneria salicis (formerly Erwinia salicis ) – This vascular pathogen spreads within the xylem of infected trees. All willow ( Salix ) species are more or less susceptible. The bacteria invade the wood of diseased trees, overwintering within the tree and invading new annual rings each year, often by way of feeding tunnels left by insects. The role of insects in local spread of the disease has not been proven. Spread is known, however, to occur as a result of propagation of diseased willow. Found in Japan and Europe (Belgium, Britain, Germany, Netherlands, Austria [reported, but not confirmed]).

Virus and Virus-like Problems

Blackberry yellow vein — Blackberry yellow vein associated virus ( BYVaV ) and Blackberry virus Y . – Blackberry yellow vein disease has emerged in blackberries in the Southern and Southeastern United States causing significant losses and in some cases, plant death. Blackberry yellow vein disease is caused by co-infection of at least two viruses with as many as five viruses detected in symptomatic plants. The virus complex can vary significantly with more than a dozen viruses identified from plants exhibiting these symptoms. Blackberry yellow vein is a disease with symptoms similar to those attributed to Tobacco ringspot virus . Using nematodes to transmit Tobacco ringspot virus from symptomatic plants to blackberry plants free of known viruses showed that plants singly infected with Tobacco ringspot virus are symptomless. Symptoms of blackberry yellow vein disease include progressive leaf vein yellowing, poor fruit flavor, dieback of floricanes, and bush decline. Vein yellowing occurs on floricanes and primocanes, with young leaves on primocanes appearing symptomless. An electron microscopic examination of sap from symptomatic leaf tissue can reveal flexuous rodshaped virus particles, but this is not a suitable means for detection.

Plum pox — Plum pox potyvirus – The disease was found in North America for the first time in 1999 in Pennsylvania and has now been detected in New York and Michigan as well as Ontario and Nova Scotia, Canada. This resulted in an immediate quarantine on U.S. Prunus nursery stock headed for Canada cherry nursery stock was later removed from the quarantine. Surveys for the virus in 2000 and 2006 did not find the virus in the Pacific Northwest nursery industry or cherry orchards. After years of eradication efforts, Pennsylvania was declared free of the virus in 2009, meeting the requirement of three consecutive years of testing negative. Known strains include D, which has been found in Pennsylvania, M (most severe), C (cherry), and Ea (El Amar). Globally, PPV is the most economically important virus of stone fruits. PPV infects all Prunus fruit tree species, almond, and many ornamental trees. In Europe, wild Prunus species are reservoirs of the virus. PPV is transmitted by aphids in a nonpersistent manner and is retained by the aphid for no more than a few hours. Aphids appear to spread the virus not to immediately adjacent trees but to trees several spaces away. Systemic spread of the virus within a tree may take several years in the meantime, the virus may be distributed very irregularly. Long-distance spread is through distribution of infected budwood and nursery stock.

Sheep Pen Hill Disease in New Jersey — New Jersey strain (BlScV-NJ) – Blueberry scorch virus (BBScV) was first observed in a Berkeley blueberry planting near Puyallup, Washington in 1980 and has been observed in western Oregon and Washington (near Puyallup and in Clark County), in the Fraser River Valley of British Columbia in 2000, and Whatcom County in northern Washington in 2012. BlScV with more severe symptoms was reported in British Columbia during the summer of 2000. Based on symptoms, it closely resembles the New Jersey strain of BlScV, known there as ‘Sheep Pen Hill Disease.’ It is appears that the greatest diversity of BlScV is in B.C., suggesting that virus originated there, likely in a native Vaccinium or related species. The New Jersey strain of BlScV causes symptoms in all cultivars except ‘Jersey’, whereas the west coast strain is symptomless in ‘Bluecrop’ and ‘Duke’ as well as several other cultivars. Since BlScV was found throughout the main blueberry production areas of BC, all planting material from BC should be considered suspect and potentially infected with the virus.

Potato cyst nematodes — Globodera pallida and Globodera rostochiensis

Pale Potato Cyst Nematode — Globodera pallida – Wide distribution in potato-growing regions of Europe. It has been reported from South America, Asia, Africa and Newfoundland and was confirmed in Idaho during 2006. The pest was confirmed in seven infested fields totaling 911 acres, within a one-mile radius in Bingham and Bonneville Counties, Idaho. The infested fields, and an area surrounding the fields, were placed under a Federal Domestic Quarantine Order and parallel State Rule in August 2006, establishing restrictions on movement of certain regulated articles from Idaho in order to prevent the spread of G. pallida . As a result of ongoing intensive soil sampling, an additional 20 infested fields have been found in the area. All 27 infested fields lay within an 8.5-mile radius. Fields associated through shared tenancy, farming practices, equipment, and/or shared borders have been extensively surveyed and are also regulated. Very narrow range: potato, tomato, and some weeds.

Golden nematode — Globodera rostochiensis – Although this nematode is not currently on the “100” list, it is a cyst nematode of quarantine importance. It was found in 1965 on the southern portion of Vancouver Island BC. Restrictions have reduced the number of sites that have tested positive but two sites remain infested. The nematode was discovered in the United States near Hicksville, Long Island, NY in 1934 when a farmer noticed a few isolated spots where the vines were stunted and off-color. The nematode had probably been present 20 years in the original field before it was identified. The first infestation outside Long Island was discovered in Steuben County, NY in December 1967. Additional infestations have been discovered since in upper New York State in other counties. Regulations are in effect for the two agricultural counties of Long Island and seven upstate New York counties. Commercial plants infected by this nematode are potato, tomato, and eggplant. Wild plants known to be infected all belong to 90 species of Solanum, several of which are found in this country, but most are found in South America, the indigenous range of the nematode.

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