Bacterial canker ravages processing tomatoes, Learn how to recognize bacterial canker now to manage this disease in the future.
How to spot and stop diseases on greenhouse tomato seedlings: Stop diseases now on tomato seedlings and produce healthy transplants for the field, Mary Hausbeck, Michigan State University Extension.
Managing Perennial Weeds in Tomatoes, This Focus on Tomato webcast by Steve Weller at Purdue University summarizes different perennial weed types, shows examples of problem perennial weeds, and discusses techniques available for managing these weeds.
MSU’s Research results for bacterial canker in tomatoes, Research indicates it is best to manage canker before field planting tomatoes. Mary Hausbeck, Michigan State University Extension.
Protect tomato transplants in the greenhouse from bacterial diseases. Mary Hausbeck, Michigan State University Extension. Although some details are specific to Michigan, the general principles in this post apply to all tomato transplant production operations.
Protect tomato transplants in the greenhouse from fungal diseases. Mary Hausbeck, Michigan State University Extension. Although some details are specific to Michigan, the general principles in this post apply to all tomato transplant production operations.
Tomato Disease Guide (pdf) – A Practical Guide for Seedsmen, Growers and Agricultural Advisors. Published by Seminis Vegetable Seeds, Inc.’s Plant Health Department.
Tomato Diseases Favored by High Tunnel Greenhouses (recorded webscast, Dec. 2013)
By Judson Reid, Extension Vegetable Specialist, Cornell University.

Diseases

Alternaria

Disease: Alternaria
Pathogen: Alternaria solani

Alternaria symptoms on tomato-2 — **Photo Source:** D.A. Inglis

Alternaria symptoms on tomato-3 — **Photo Source:** D.A. Inglis

Alternaria symptoms on tomato-4 — **Photo Source:** D.A. Inglis

On-Line Resources:

Early Blight Management for Organic Tomato Production, eXtension.

Return to the Top

Big bud

Disease: Big bud
Pathogen: Beet leafhopper transmitted viresence agent (BLTVA), a phytoplasma, transmitted by the beet leafhopper, Circulifer tenellus
Host crops: Tomato and several other plant species, including potato.

big bud symptoms on tomato-2 — **Photo Source:** Phil Hamm, Oregon State University

On-Line Resources:

Tomato: Tomato Big Bud, How to Manage Pests: UC Pest Management Guidelines, UC IPM Online, University of California.
Virus Diseases and Disorders of Tomato: Big Bud, Vegetable MD Online, Cornell University.

Return to the Top

Buckeye rot

Disease: Buckeye rot
Pathogen: Non pathogenic disorder

Return to the Top

Curly top

Disease: Curly top
Pathogen: Beet curly top virus (BCTV), vectored by the beet leafhopper Circulifer tenellus
Host crops: Numerous plant species including many vegetables such as bean, beet, carrot, eggplant,
coriander, pepper, potato, tomato, and various cucurbits such as squash, cucumber, pumpkin, and watermelon, etc.

tomato plants showing symptoms of beet curly top virus — Symptoms of curly top on tomato leaves.
**Photo Source:** Phil Hamm, Oregon State University

symptoms of beet curly top virus on tomato plants — Symptoms of curly top on tomato leaves.
**Photo Source:** Phil Hamm, Oregon State University

symptoms of beet curly top-1 — Symptoms of curly top on tomato leaves.
**Photo Source:** Phil Hamm, Oregon State University

tomato plants showing symptoms of beet curly top virus-4 — Symptoms of curly top on tomato leaves.
**Photo Source:** Krishna Mohan, University of Idaho

tomato plants showing symptoms of beet curly top virus-5 — Symptoms of curly top on tomato leaves.
**Photo Source:** Krishna Mohan, University of Idaho

On-Line Resources:

Pacific Northwest Plant Disease Management Handbook: Tomato (Lycopersicon esculentum) – Curly Top.
Tomato: Curly top (Beet curly top virus), Washington State University Hortsense.
Curly Top Disease of Tomato, Plant Management Network International.

Return to the Top

Late blight

Disease: Late blight
Pathogen: Phytophthora infestans

Late blight symptoms on tomato-2 — **Photo Source:** Matt Tregoning, Sol to Seed Farm, Carnation, WA

Late blight symptoms on tomato-3 — **Photo Source:** Matt Tregoning, Sol to Seed Farm, Carnation, WA

Late blight symptoms on tomato-4 — **Photo Source:** Matt Tregoning, Sol to Seed Farm, Carnation, WA

Late blight symptoms on tomato-5 — **Photo Source:** Matt Tregoning, Sol to Seed Farm, Carnation, WA

On-Line Resources:

Pacific Northwest Plant Disease Management Handbook: Tomato (Lycopersicon esculentum) – Late Blight.
Organic Management of Late Blight of Potato and Tomato (Phytophthora infestans), eXtension.
Protect tomatoes in the greenhouse from late blight, Michigan State University.
Tomato: Late blight, Washington State University Hortsense.

Return to the Top

Leaf mold

Problem: Leaf mold
Pathogen: Fulvia fulva (formerly Cladosporium fulvum)

leaf mold on bottom of tomato leaf-2 — **Photo Source:** Carol Miles, Washington State University

symptoms of leaf mold on tomato-3 — Very severe symptoms of leaf mold of tomato, caused by *Fulvia fulva,* in a hoophouse in western Washington as a result of high humidity caused by warm days and cool nights in late summer.
**Photo Source:** Sacha Buller, Washington State University Skagit Co. Extension Master Gardener Coordinator

symptoms of leaf mold on tomato-4 — Very severe symptoms of leaf mold of tomato, caused by *Fulvia fulva,* in a hoophouse in western Washington as a result of high humidity caused by warm days and cool nights in late summer.
**Photo Source:** Sacha Buller, Washington State University Skagit Co. Extension Master Gardener Coordinator

symptoms of leaf mold on tomato plant-3 — Very severe symptoms of leaf mold of tomato, caused by *Fulvia fulva,* in a hoophouse in western Washington as a result of high humidity caused by warm days and cool nights in late summer.
**Photo Source:** Sacha Buller, Washington State University Skagit Co. Extension Master Gardener Coordinator

symptoms of leaf mold on tomato-6 — Very severe symptoms of leaf mold of tomato, caused by *Fulvia fulva,* in a hoophouse in western Washington as a result of high humidity caused by warm days and cool nights in late summer.
**Photo Source:** Sacha Buller, Washington State University Skagit Co. Extension Master Gardener Coordinator

On-Line Resources:

Greenhouse Plants, Tomato-Leaf Mold, PNW Plant Disease Management Handbook.
Tomato leaf mold in hoophouse tomatoes. Authors: Marissa Schuh and Benjamin Phillips. Michigan State University Extension, 2019.
Tomato (Lycopersicon esculentum)-Leaf Mold, PNW Plant Disease Management Handbook.

Return to the Top

Pythium rot

Disease: Pythium rot
Pathogen: Pythium species

Return to the Top

Verticillium wilt

Disease: Verticillium wilt
Pathogen: Verticillium species
Host crops: Numerous vegetables including many brassica vegetables (but not broccoli), cucumber,
eggplant, pepper, potato, pumpkin, radish, spinach, tomato, watermelon, etc.

Verticillium wilt on tomato-2 — **Photo Source:** Lindsey du Toit

Verticillium wilt on tomato-3 — **Photo Source:** Lindsey du Toit

Verticillium wilt on tomato-4 — **Photo Source:** Lindsey du Toit

On-Line Resources:

Pacific Northwest Plant Disease Management Handbook: Tomato (Lycopersicon esculentum) – Wilts {Fusarium wilt, Verticillium wilt}.
Tomato: Verticillium wilt, Washington State University Hortsense.
See Diseases, pests, and other problems common to many vegetables: Verticillium wilt.

Return to the Top

White mold

Disease: White mold
Pathogen: Sclerotinia species
Host crops: Bean, various brassica vegetables, carrot, eggplant, lettuce, potato, tomato, etc.

White mold on stem — Tomato stem white mold mycelium and sclerotia.
**Photo Source:** Jenny Glass, WSU Puyallup PIDL

On-Line Resources:

Pacific Northwest Plant Disease Management Handbook: Tomato (Lycopersicon esculentum) – White Mold.
Tomato: White mold, Washington State University Hortsense.
See Diseases, pests, and other problems common to many vegetables: White mold.

Return to the Top

Insect/Mite Pests

Flea beetle

Common name: Flea beetle
Latin binomial: Pictured is the western potato flea beetle, Epitrix subcrinita, but the tuber flea beetle, Epitrix tuberis, may also damage foliage.
Host crops: Eggplant, pepper, potato, and tomato.

adult potato flea beetle — The adult flea beetle is small (~1/16 inch long), oblong, and dark brown to bronze in color.
**Photo Source:** Michael Bush, WSU Extension, Yakima, WA

adult potato flea beetle showing enlarged hind legs — The most distinctive feature of the flea beetle is the enlarged hind legs that provide the insect the ability to jump considerable distances when approached or disturbed.
**Photo Source:** Michael Bush, WSU Extension, Yakima, WA

On-Line Resources:

Potato Flea Beetles: Biology and Control (pdf), Washington State University Extension Bulletin 1198E.
Potato Flea Beetles. Coleoptera: Chrysomelidae Western Potato Flea Beetle Epitrix subcrinita, Tuber Flea Beetle Epitrix tuberis (pdf).
Pacific Northwest Insect Management Handbook. Chapter: Irish Potatoes, Section: Flea Beetle to Grasshopper.
Vegetables: Tomato: Flea beetles. Washington State University Hortsense.
See Diseases, pests, and other problems common to many vegetables: Flea beetle.

Return to the Top

Tomato hornworm

Common name (of damaging stage): Tomato hornworm
Latin binomial: Manduca quinquemaculata
Host crops: Pepper, eggplant, potato, and tomato.

tomato hornworm-2 — Tomato hornworm is a plant defoliator feeding on entire leaves, small stems, and even parts of immature fruit. Often this defoliation is first noticed near the end of the growing season (August or early September) when the hornworm is approaching maturity.
**Photo Source:** Michael Bush, WSU Extension, Yakima, WA

tomato hornworm on ground — The tomato hornworm has one generation per year and overwinters as a pupa in the soil. Adults will emerge in the spring.
**Photo Source:** Michael Bush, WSU Extension, Yakima, WA

measuring the size of a tomato hornworm adult — The tomato hornworm adult is a large (3.5 to 5.25-inch wingspan) moth known as the five-spotted hawk moth for the five pairs of orange spots on the abdomen. The adult is rarely encountered by growers and home gardeners as it tends to fly around dusk.
**Photo Source:** Michael Bush, WSU Extension, Yakima, WA

On-Line Resources:

Pacific Northwest Insect Management Handbook. Washington State Chapter: Vegetables, Section: Tomato Part2: Fleabeetle to Wireworm.
Vegetables: Tomato: Tomato hornworm. Washington State University Hortsense.
UC Pest Management Guidelines: Tomato Hornworms. UC IPM Online, University of California.

Western flower thrips

Common name (of damaging stage): Western flower thrips
Latin binomial: Frankliniella occidentalis
Host crops: Basil, Broccoli, Cabbage, Cauliflower, Cucumber, Onion, Potato, Pumpkin, Squash, Tomato, and Watermelon.

immature Western flower thrips — An immature Western flower thrip resembles the adult, but is smaller, wingless and translucent yellow in color. There may be multiple generations per year and thrips may invade vegetable fields when alternate flowering plants dry up in the summer or when an adjacent host crop is harvested.
**Photo Source:** Michael Bush, WSU Extension, Yakima, WA

cosmetic damage to tomato fruit by thrips — Thrips rasp (by puncturing individual surface cells and sucking cellular contents) the surface of flower and fruit tissues as they feed. Their feeding can weaken and deform flowers and reduce flower viability. The most visible damage is caused when they rasp the surface of the fruit in areas where two fruit come in contact or when a leave lies up against the fruit. This damage is cosmetic only and does not extend beneath the fruit skin.
**Photo Source:** Michael Bush, WSU Extension, Yakima, WA

On-Line Resources:

Western Flower Thrips Thysanoptera: Thripidae Frankiniella occidentalis.
Pacific Northwest Insect Management Handbook. Chapter: Vegetables, Section: Broccoli, Cabbage, Other Crucifers.
Pacific Northwest Insect Management Handbook. Chapter: Vegetables, Section: Cucumber (garden symphylan to wireworm).
Vegetables: Bean: Thrips. Washington State University Hortsense.
Vegetables: Broccoli, Cole crops: Thrips. Washington State University Hortsense.
See Diseases, pests, and other problems common to many vegetables: Western flower thrips.

Return to the Top

Abiotic Problems Common to Tomato

2,4-D herbicide injury

Problem: 2,4-D herbicide injury

On-Line Resources:

2,4-D on Tomato: Postemergence. Video of injury to a tomato plant from a postemergence application of the herbicide 2,4-D. Jerry L. Hill, Ed Peachey, Larry C. Burrill, and Craig Anderson, Oregon State University.

Return to the Top

Blossom end rot

Problem: Blossom end rot
Cause: Calcium deficiency resulting from various environmental conditions and management practices, e.g., inadequate Ca in the soil, inconsistent water as a result of alternating wet and dry periods that decrease Ca uptake by plants, and even excellent growing conditions such as a period of very bright sunshine and warm temperatures mid-season.
Crops affected: Tomato, pepper, eggplant, and various cucurbits.

damaged tomato fruit — Symptoms of blossom end rot on tomato fruit.
**Photo Source:** Carol Miles, Washington State University

symptoms of blossom end rot on tomato fruit — Blossom-end rot is a physiological disorder that first appears as a water-soaked, light brown spot on the distil end of the fruit. As the fruit matures, the spot becomes sunken, leathery, and brown to black. Secondary pathogens can infect the area, causing fruit rot. The disorder is more common on earliest maturing fruit. Blossom end rot is associated with a low concentration of calcium in developing fruit. In eastern Washington, this is often caused by excessive soil moisture fluctuations, drought stress, or excessive nitrogen fertilization. Soil surface mulches, appropriate irrigation timing and frequency, soil amendment with limestone, and foliar applications of calcium may reduce the incidence of this disorder.
**Photo Source:** Mike Bush, WSU Yakima Co. Extension Educator

symptoms of blossom end rot on pepper — Blossom-end rot is a physiological disorder that first appears as a water-soaked, light brown spot on the distil end of the fruit. As the fruit matures, the spot becomes sunken, leathery, and brown to black. Secondary pathogens can infect the area, causing fruit rot. The disorder is more common on earliest maturing fruit. Blossom end rot is associated with a low concentration of calcium in developing fruit. In eastern Washington, this is often caused by excessive soil moisture fluctuations, drought stress, or excessive nitrogen fertilization. Soil surface mulches, appropriate irrigation timing and frequency, soil amendment with limestone, and foliar applications of calcium may reduce the incidence of this disorder.
**Photo Source:** Mike Bush, WSU Yakima Co. Extension Educator

On-Line Resources:

Blossom-end-rot on Tomatoes. By M. Ophardt, 2013. WSU Extension Garden Tips.
Blossom end rot: Understanding a perennial problem. Michigan State University Extension.
Blossom-End Rot of Tomato, Pepper, and Eggplant. By Miller, S.A., R. C. Rowe, and R. M. Riedel, The Ohio State University Extension Fact Sheet HYG-3117-96.
Blossom-end Rot of Tomatoes (pdf). Oregon State University Extension Service Bulletin FS 139. By I.C. MacSwan, 2000. Oregon State University Extension Service Bulletin.
Vegetables: Tomato: Blossom-end Rot. Washington State University Hortsense.
See Diseases, pests, and other problems common to many vegetables: Blossom end rot of vegetables.

Return to the Top

Parthenocarpy in tomato fruit

Problem: Parthenocarpy (secondary ovary formation) in tomato fruit
Cause: Various environmentally stressful conditions
Crops affected: Tomato and many other vegetables.

On-Line Resources:

Parthenocarpy, Wikipedia.

Return to the Top

Physiological leaf roll

Problem: Physiological leaf roll
Cause: Various environmental conditions and management practices
Crops affected: Tomato and Potato.

Tomato Physiological leaf roll — **Photo Source:** PNW VEG members

Physiological leaf roll symptoms — **Photo Source:** PNW VEG members

On-Line Resources:

Physiological Leaf Roll of Tomato/Potato (pdf), Identification & Management of Emerging Vegetable Problems in the Pacific Northwest. Pacific Northwest Vegetable Extension Group.
Physiological Leaf Roll of Tomato (pdf), A Fact Sheet prepared by The Pacific Northwest Vegetable Extension Group.

Return to the Top

Vivipary

Problem: Vivipary (germination of seeds while still attached to the mother plant)
Crops affected: Solanaceaous vegetables like tomato and pepper.

On-Line Resources:

Effect of potassium nutrition during bell pepper seed development on vivipary and endogenous levels of abscisic acid (ABA). (pdf). By Marrush, M., M. Yamaguchi and M. E. Saltveit. 1998. J. Amer. Soc. Hort. Sci. 123(5):925–930.
Physiological and Nutrient Disorders (pdf). University of Kentucky Vegetable Integrated Pest Management Program. Vegetable Manuals.
See Diseases, pests, and other problems common to many vegetables: Vivipary.

Return to the Top

PDF Accessibility

If you need the content provided on this site in an alternate format or for further information on the Vegetable Seed Pathology program,

please contact: Lindsey du Toit at dutoit@wsu.edu or at 360-848-6140.

Our pages provide links to external sites for the convenience of users. WSU Extension does not manage these external sites, nor does Extension review, control, or take responsibility for the content of these sites. These external sites do not implicitly or explicitly represent official positions and policies of WSU Extension.