| SYMPTOMS |
CAUSES |
CONTROLS |
| Dark brown irregular spots with
target rings and yellow haloes develop on leaves, stems, and
fruit; spots on fruit are often at stem end and are sunken |
• Early blight (fungal disease) |
• Resistant varieties; use registered
fungicide; remove old plant debris; rotate tomatoes with beans
or sweet corn |
| • Phoma rot (fungal disease) |
• Phoma rot is not as common as
early blight and you will be safe recommending early blight
controls |
| Uniformly small (1/8")
chocolate brown spots or dark spots with tan centers develop on
leaves from bottom of plant to top; spots sometimes form on
stems but never on fruits; leaves shrivel |
• Septoria leaf spot (fungal
disease) |
• Use registered fungicide; remove old
plant debris |
| • Bacterial spot |
• Not as common as Septoria leaf
spot; control for bacterial spot is to use chlorox treated seed
and Kocide spray if available |
| Flowers do not set fruit and drop
from plant |
• Night temperatures are below 55 degrees |
• Wait until temperatures
become more favorable; it may help to shake the flowers by
gently tapping the stems to effect self-pollination |
| • or day temperatures exceed 90 degrees F |
| Light tan spots on upper leaf surfaces; dense
olive green moldy growth on undersurface of spots |
• Gray leaf mold (fungal disease) |
• Mainly a greenhouse problem: provide
adquate ventilation to avoid high humidity; fungicides used to
control other diseases will control this disease in the garden |
| Small (1/8") chocolate brown spots on
leaves and fruit; spots on fruit are raised |
• Bacterial spot |
• Use chlorox treated seed; avoid
overhead watering; use fixed copper bactericide (e.g. Kocide) if
available locally; remove old plant debris; rotate |
| Large, sunken, tan watersoaked spot develops
on blossom end of fruit; spot turns black and mold may grow |
• Blossom end rot, caused by calcium
deficiency to developing fruits |
• Calcium deficiency is a problem when
developing fruits receive uneven moisture: supply water during
dry periods; mulch |
| General browning of tomato skin; brown
speckling of walls between seed cavities apparent when fruit is
cut open |
• Internal browning (virus disease) |
• Resistant varieties (to tobacco mosaic
virus); weed control; do not handle healthy plants after
diseased ones; remove affected plants |
| Extreme malformation and scarring of fruit |
• Catfacing, caused by cool weather or
herbicide injury during fruit formation |
|
| Tiny white winged insects on undersides of
leaves |
• Whiteflies |
• Yellow sticky boards (smeared with
grease) will attract and trap adults or use registered
insecticide |
| Yellow-orange blotches that do not ripen at
stem end of fruit or white, papery spot on side of fruit facing
sun |
• Sunscald |
• Prevent foliar diseases that cause leaf
drop and expose fruits to sun |
| Leaves distorted with "strapped"
or feathery look (leaves narrower than normal, tips stretched
out into thin projection, veins very close together) |
• Herbicide injury |
• Do not spray lawn herbicides during hot
weather; spray after wind has died down in late afternoon |
| • Cucumber mosaic (virus disease) |
• It is impossible to distinguish these
two problems based on symptoms alone; however, if sample comes
in during spring when lawn herbicides are being sprayed,
strongly suspect herbicide injury; virus is controlled by
removing affected plants,weed control and aphid control |
| Leaves roll upward, feel leathery, but remain
green; plants are not stunted |
• Excess water |
• Common physiological disorder after wet
periods; varieties Big Boy, Floramerica, and Beefsteak are
especially susceptible |
| Plants wilted; bottom leaves may turn yellow;
brown discoloration inside stem |
• Verticillium wilt |
• Rotate tomatoes with cereals, grasses,
or legumes; avoid rotation with potatoes, peppers, or eggplant;
resistant varieties |
|
• Walnut wilt, caused by toxin from
walnut or butternut trees |
• Do not plant tomatoes near trees; sever
roots bordering garden and place barrier between tree and garden |
|
• Waterlogged soil |
• Improve drainage |
| Plants stunted, wilted, and yellow; nodules on
roots |
• Root knot nematode |
• Rotate; remove old plant debris; soil
pasteurization if necessary |
| Young plants cut off at ground level |
• Cutworms |
• Use cutworm collars or registered
insecticide |
| Young plants with many tiny holes in leaves |
• Flea beetles |
• Tomatoes will tolerate a lot of flea
beetle damage if they are healthy; when necessary, use
registered insecticide |
| Large holes in leaves; caterpillars present |
• Tomato hornworm |
• Handpick, spray with registered
insecticide or B. thuringiensis spores |
