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Problem
(factsheet)
Plant NameTypeDescription 
AnthracnoseTomatoDiseaseTomato anthracnose is a fungal disease primarily seen on ripe fruit. It may sometimes affect leaves. Leaf symptoms are most common on older leaves, which show small, dark spots surrounded by a yellow halo. Fruits may be infected while green, but symptoms are seen on ripe fruit. Infected fruits initially show circular, sunken, water-soaked spots. The spots enlarge to about 1/2" in diameter and become darker. They often show concentric ring markings around a tan center. Dark specks may be present on the tan area. During damp weather, masses of salmon-colored spores may develop on the surface of the lesion. The fungus frequently overwinters on diseased plant debris and can also infect other crop and weed species. Wet soils favor disease development.
Blossom-end rotTomatoDiseaseBlossom end rot is a physiological problem affecting tomato fruit. A tan, water-soaked lesion develops near the blossom scar on the end of the fruit. The lesion enlarges, turns black and leathery, and can eventually involve up to 1/3 or more of the fruit. Affected tomatoes are flattened or concave on the blossom end. Occasionally, blossom end rot may occur on the side of the fruit or may cause discoloration of the internal tissues without external symptoms. Blossom end rot is caused by insufficient calcium in the end of the fruit. Inconsistent soil moisture and high temperatures are often factors involved in this problem. It can be caused by several factors including drought, overwatering, root damage, insufficient soil calcium levels, or high concentrations of salts in the soil. Varieties differ greatly in their susceptibility to this problem.
CatfaceTomatoDiseaseCatface is a physiological problem affecting tomato fruit. Damage to blossoms, cold temperatures during fruit set, exposure to growth-hormone-type herbicides, and abnormal growing conditions are among the possible causes of catface. Affected fruits are mildly to severely misshapen and scarred at the blossom end. They appear puckered and lumpy. Catfaced fruit typically ripen unevenly and are of poor quality. Large-fruited varieties seem to be particularly susceptible.
Curly top (Beet curly top virus)TomatoDiseaseCurly top is caused by a virus transmitted by the beet leafhopper. Many crops are affected, including tomato, bean, squash, beet, spinach, cucumber, and pepper. Typical symptoms of the disease include puckering and upward rolling and twisting of leaves, followed by a general yellowing of the plant. Young plants may be killed. Older plants are yellowed and dwarfed, with stunted growing tips. Leaves are thickened and brittle or leathery in texture. Leaf veins may be purplish. The virus is also found in annual flowers and weeds. Curly top is becoming increasingly common in western Washington.
Late blightTomatoDiseaseLate blight of tomato is caused by a fungus which also causes disease on potato, eggplant, and other members of the potato family (Solanaceae). Gray-green, water-soaked spots appear on leaves, stems, and fruit. These quickly enlarge into dark blotches. The disease may spread to affect all aboveground portions of the plant. The brown blotches on infected fruits are firm and appear corrugated or wrinkled. These usually appear first on the upper portion of the fruit and may sometimes involve whole fruits. During moist weather, a sparse growth of whitish fungal mycelia may be seen on fruit lesions and on the underside of leaf lesions. Disease development is favored by cool, rainy weather and may be more severe under sprinkler irrigation. The fungus overwinters primarily on infected potato tubers and is spread by wind.
Mosaic virusesTomatoDiseaseSeveral viruses can cause mosaic symptoms in tomatoes, including tobacco mosaic virus (TMV), tomato mosaic virus (ToMV), and cucumber mosaic virus (CMV). Symptoms caused by TMV and ToMV are similar. Leaves show green mottling and may be curled, stunted, and slightly deformed. Plants may be stunted and are generally somewhat yellowed. Fruit is not usually affected but may be small and ripen unevenly. An internal browning of fruit may also occur. TMV and ToMV can be spread by tools, hands, and clothing. Symptoms of CMV include leaves with yellow mottling, bushy and stunted plants, and a reduced yield of small, slow-to-mature fruit. The most striking symptom of CMV infection is the shoestring-like appearance of some leaves. CMV has a wide host range and may be spread by aphids.
Physiological leaf rollTomatoDiseasePhysiological leaf roll of tomato is a cultural problem which may be associated with high soil moisture, high temperature, drought, or heavy pruning. Plants with a heavy fruit load are often more severely affected. The leaves of the plants roll upward and become leathery. Symptoms may resemble those caused by virus diseases, but plants remain green and are not stunted or deformed. Growth is not usually affected. This problem causes no apparent damage to the plants and does not reduce yield. Varieties differ greatly in their susceptibility to this problem.
SunscaldTomatoDiseaseSunscald of tomato fruits frequently occurs in hot, dry weather, but may occur whenever green fruit is suddenly exposed to direct sun. The sunward side of green fruit develops a yellowish, light brown, or white leathery patch, which may become wrinkled or blisterlike as the fruit matures. On ripe tomatoes, the damaged areas appear as flattened, grayish-white patches with a papery texture. The spots are sometimes attacked by rot organisms, causing fruit decay.
Verticillium wiltTomatoDiseaseVerticillium wilt is caused by a fungus commonly found in the soil. Many species of plants are affected by Verticillium. Tomato and potato are favored hosts. Infected plants wilt, are stunted, and have yellow leaves which tend to roll inward. Yellowing occurs first on the lower leaves. Leaves dry out, turn brown, and die. The vascular tissues are discolored (noticeable when cuts are made into stems). Typically, the fungus attacks the roots and moves throughout the plant via the vascular system. Young plants may be killed. Older plants generally suffer from decreased growth and lower yields.
White moldTomatoDiseaseWhite mold is caused by a fungus. It typically attacks dead flower petals or dead leaves, then spreads into living tissues. The infection often starts in branch crotches or at the base of stems. Initial symptoms may include a rapidly spreading soft rot. Affected tissues turn gray and may be covered with a mass of cottony, white fungal growth. Hard, black fungal structures (measuring 1/4" to 1") are often produced on the cottony growth and inside the affected stems. Infected stems may be tan, then eventually turn a bleached, bone-like white. Disease development is favored by long periods of cool, wet weather.
AphidsTomatoInsectSeveral species of aphids may feed on tomato. They are soft-bodied, pear-shaped insects which may be yellowish, pink, green, or black in color. They are usually found feeding in large colonies on new growth and on the undersides of leaves. Aphid feeding may cause foliage to turn yellow and wilt. Feeding aphids also secrete honeydew, a sweet, sticky material which may attract ants or become covered with sooty mold.
Brown marmorated stink bugTomatoInsectThe brown marmorated stink bug (BMSB) is an introduced pest species from Asia that is spreading quickly across the United States. Nymphs and adults feed on a wide variety of plant hosts. BMSB prefers to feed on fruit, seeds, and seed pods, but will also feed on stems and leaves of some hosts. Both adults and nymphs have piercing-sucking mouthparts and inject digestive enzymes into plant tissues to aid in feeding. On the surface of immature tomato fruit (green through pink stage), BMSB damage appears initially as a pinprick surrounded by a light discolored spot. The injured areas may turn yellow or decay as the fruit matures, and overall, the fruits may become distorted or catfaced. On the surface of ripe fruit, damage appears as whitish or yellow spots about 1/2 inch in diameter. The surface spots often appear slightly sunken as whitish corky or spongy areas develop under the skin. Secondary damage from rot may occur at the feeding site and severely damaged fruits may rot on the vine. Other known vegetable hosts of BMSB include peppers, corn, beans, and cucumbers. One or two generations of BMSB per year are expected in the Pacific Northwest. Adults overwinter in sheltered locations (including houses, where they can become a significant nuisance pest). In the spring, light green to white eggs are laid in groups of about 20 to 30 on the underside of leaves. Young stink bugs, or nymphs, are black with a red-and-black striped abdomen. Nymphs often feed in groups when young. Older nymphs are dark with white bands on body, legs, and antennae. They may feed in groups or singly. Adults are a little over 1/2 inch long, with a shield-shaped body. Body color on adults is mottled gray and brown, while the legs and antennae have alternating dark and light bands. The abdomen also has dark and light bands which are visible at the edge of the wings. NOTE: BMSB adults closely resemble other stink bugs found in WA and OR. For more information on BMSB identification, see FS079E, Pest Watch: Brown Marmorated Stink Bug, available at https://pubs.wsu.edu/.
Colorado potato beetleTomatoInsectThe adult Colorado potato beetle is a broad (1/4" wide), yellow-and-black striped beetle up to about 3/8" in length. The adults overwinter in the soil, emerging in the spring. They lay clusters of yellow eggs on the underside of the leaves of host plants. The humpbacked larvae are reddish-orange and have two rows of black spots along each side. Both larvae and adults chew holes in leaves and leaf margins. They may cause serious defoliation. Other plants which may be attacked include pepper, potato, petunia, and other tomato relatives including weeds such as nightshade and groundcherry.
Flea beetlesTomatoInsectFlea beetles are small, brown to metallic black beetles with a habit of jumping like fleas when disturbed. They feed on many plants including potatoes, beets, kale, collards, radish, and many weeds, particularly those in the mustard family. Adults eat small round holes in the leaves, usually early in the season. The larvae typically feed on underground portions of the host plants. Damage can be very severe on seedling plants.
SlugsTomatoInsectSlugs are common garden pests in western Washington. They resemble snails, but lack shells. They may vary in size from as little as 1/4" up to several inches in length, depending on age and species. Foliage of older plants is raggedly chewed, while younger plants may be totally consumed. Slugs leave behind a characteristic slime trail, which appears silvery when it dries. Slugs typically feed at night and do more damage during cool, moist weather.
Spider mitesTomatoInsectSpider mites are tiny, eight-legged mites which range in color from yellowish to green or red. They typically feed on the underside of leaves, causing a yellowish to bronze stippling or speckling of leaves. Severe infestations can cause entire leaves to turn yellow. Spider mite feeding is usually accompanied by webbing on the underside of leaves. The mites may be visible as "moving dust" in the webbing. Mite infestations are worse in hot, dry, dusty conditions.
Tomato hornwormTomatoInsectThe tomato hornworm is the larva of a sphinx moth. The adult moth has a wingspan of up to 4"-5". Wing color is generally mottled gray. Mature caterpillars may reach up to 5" in length but are typically around 2" long. They are generally pale green with some white markings, although dark purple hornworms are sometimes seen. The mature hornworms are characterized by a short, curved, green to reddish horn on the back end. The larvae feed on the leaves of tomato, potato, and related plants and may cause serious defoliation. Symptoms of feeding include leaves chewed down to the midrib and dark pellets of frass (excrement) on or under plants.