A Visual Guide: Tomato Foliage, Stem & Root Problems

1 Page 1 of 7 Visit us on the Web: Visual guide : Tomato Foliage, Stem & Root ProblemsDisease preventionThis guide lists the most common foliar Problems of tomatoes (forproblems on fruit, see our Visual guide : Tomato Fruit Problems ), butpreventing Problems is usually easier than curing them. So, here are tenstrategies to help prevent diseases and other Problems :1. Although many heirloom varieties have better flavor than newervarieties, they lack disease resistance. Purchasing disease resistantcultivars can help, but keep in mind that disease resistance doesnot mean immunity. Preventive strategies are still tools, Tomato cages and stakes with a solution of one partbleach to nine parts Rotate the planting location every three to five Do not plant in cold soils. This weakens plants making them moresusceptible to diseases and may stunt them Do not crowd tomatoes.

2 Good air circulation around plants is vitalin keeping the foliage dry and preventing lower branches, leaving the stem bare up to the first set offlowers and then mulch (straw is a good choice). Many fungaldiseases are in the soil or in bits of plant material left over fromprevious years. When it rains, fungal spores splash up onto thelower leaves, infecting them. The next time it rains, the spores fromthe infected leaves splash up onto the next set leaves. Uncheckedthe infection will spread all the way to the top of the in the morning to give the foliage time to dry out any diseased looking leaves as soon as a spray program becomes necessary, use a fungicide (such as,chlorothalonil) alternated with a copper based fungicide to helpwith bacterial diseases because even an expert can have difficultydistinguishing between fungal diseases and bacterial : fungicides do not cure fungal diseases; they can only preventthem from the end of every growing season, remove as much of the plant aspossible from the garden and do not more information about care and culture of tomatoes, includingfertilizing, see our Kemper Factsheet: Tomatoes.

3 For more informationabout Tomato Problems , see our Kemper Factsheet Tomato Diseases 2 of 7 Failure to set fruit or poor fruit set1. Night temperatures above 70 degrees or below 55 temperatures above 90 degrees combined with low humidityand/or drought. Hot drying winds can add to the Dry soil can cause blossoms to dry up and Too much nitrogen fertilizer produces leafy growth at the expenseof flowers and Cold soils at planting time can stunt growth and delay or Insufficient light. Tomatoes require at least 6 hours of directsunlight per Viruses, such as, curly top, mosaic viruses, etc., can affect floweringand fruit of air circulation can inhibit the movement of pollen to theflower of air circulationCrowding tomatoes can encourage moisture loving fungal diseases byblocking air circulation and keeping the foliage from drying out can also reduce fruit production by inhibiting the movement of pollento the flower pistils.

4 This movement is usually accomplished by insects orby wind shaking the pollen inside the flowers. Maintain good air-circulation by planting tomatoes at least 3 to 4 feet apart in each directionand more distance would be soilsPlanting tomatoes in cold soil may cause the leaves to turn purple from alack of potassium because tomatoes cannot absorb potassium if the soil istoo cold. The leaves will usually green up as the soil warms, but the plantsmay be stunted for the entire growing season and produce few or no them too early also exposes to the risk of a late spring freeze thatcan kill the entire plant (pictured).Lookalikes: Some tomatoes varieties have naturally purplish foliage; viraldiseases can cause stunting. Root initiatives on stemTomatoes can root along the stem and often do. This produces smallbumps or root initiatives along the stem.

5 This is not a problem. Instead itcan be used to enlarge the root system and therefore the potential healthof a plant. Dig a short trench for each plant and lay them in the trench ontheir sides, then cover them with soil. Be sure to mark the buried end toavoid accidentally injuring the plant when : Some gardeners mistake this for insects or diseasePage 3 of 7 Clemson U-USDA CESS lide Series, blightThe appearance of circular or irregular dark spots on the lower, moremature leaves is one of the first symptoms of this fungal , the spots enlarge into a series of concentric rings surroundedby a yellow area. The entire leaf may be killed and will drop off the infection typically progresses from the base of the plant, blight can result in extensive defoliation, exposing fruit to sunscaldand reducing : other leaf spot diseases and other diseases that progressfrom the bottom up; such as, septoria leaf spot, fusarium wilt, verticilliumwiltSeptoria leaf spotSeptoria leaf spot usually appears on the lower leaves after the first fruitsets.

6 Spots are circular, about one-sixteenth to one-fourth inch indiameter with dark brown margins and tan to gray centers with smallblack fruiting structures. Characteristically, there are many spots per leaf;they do not look target-like. This disease spreads upwards from oldest toyoungest growth. If leaf lesions are numerous, the leaves turn slightlyyellow, then brown, and then wither. Fruit infection is : bacterial leaf spot and speck (no tan centers); and otherdiseases that progress from the bottom upClemson U - USDA CES Slide Series, spot and speckThese are two separate but very similar diseases. Symptoms of bacterialspot are small dark brown to black circular spots, initially water-soaked,coalescing and becoming angular, sometimes with a yellow of bacterial speck are tiny, dark brown to black spots with asurrounding yellow halo.

7 Severity of both diseases is increased bywetness of fruit and foliage from sprinklers, rain, or heavy dew. Thereare some Tomato varieties with resistance to bacterial speck but very fewwith resistance to bacterial : Septoria leaf spot (tan centers)Page 4 of 7 Iron chlorosisChlorosis or yellowing of leaves can have many causes, including manydiseases, nutrient deficiencies, piercing-sucking insect or mite damageand various environmental Problems , such as, too much water andimproper soil pH. Tomatoes prefer slightly acid soil with a pH and although they will tolerate a wider pH range if the soil is well-drained and contains adequate organic mitesInfestations of spider mites result in the bleaching and stippling of infestations may cause entire leaves to become bronzed, curled,and completely enveloped in sheets of fine webbing.

8 Damage to thefoliage may result in leaf drop and reduction in the overall vitality of theplant. Lookalikes: drought stress, herbicide injury, physiological leaf roll, viraldiseases, iron Samson, Purdue University, injuryDepending on the herbicide used, symptoms can include one or more ofthe following: curling (from 2, 4-D on the right), cupping, stunted growth,discolored leaves, leaves with dead spots, and strapping, , parallelvenation (from 2,4-D on the left).Lookalikes: drought stress, spider mites, physiological leaf roll, viraldiseasesPhysiological leaf rollPhysiological leaf roll on some Tomato cultivars is normal and notharmful. It can also be a temporary condition caused by weatherconditions or by an inconsistent supply of moisture. Lack of othersymptoms (yellowing, parallel veination, lack of vigor, stunting, etc.)

9 Distinguishes it from its : drought stress, spider mites, herbicide injury, some viraldiseasesPage 5 of 7P. Bachi, UKY Research & Ed. Ctr, A. Hansen, VPISU, viruses affect tomatoes, such as, Tomato spotted wilt virus (topimage), tobacco mosaic virus (bottom image), cucumber mosaic, include leaf distortion, mosaic, mottling, ring spots, leaf curl,threadlike foliage and : drought stress, herbicide injury, physiological leaf roll, spidermites, foliar diseasesFusarium & verticillium wiltsBoth of these fungal diseases are soil-born. Fusarium often causesyellowing on one side of the plant or leaf. Yellowing begins with the older,bottom leaves, followed by wilting, browning, and defoliation. Growth istypically stunted, and little or no fruit develops. Brown, vascular tissuecan be found when the infected stem is cut at its base (top image).

10 Infected plants often die before maturing (bottom image).Verticillium is less common, usually occurring late in the season whensoils are cooler. It begins as a v-shaped blotch on lower leaves, followedby browning veins and dead, chocolate brown blotches. It spreads up theplant. Discoloration of the vascular tissue is limited to the bottom 12inches of the for tomatoes with the resistance letters VF on the plant tag or seedpacket, indicating resistance to both verticillium and fusarium : all the leaf spot diseases and bottom-up diseasesPage 6 of 7 Mary Ann Hansen, VPISU, Bachi, UKY Research & Ed. Ctr., cankerThe symptoms of bacterial canker are brown leaf margins with a yellowborder next to the inner green leaf tissue, spreading between the veins(top image). It often affects only one side of a plant.