Fungicides and Vegetable Disease Control

Fungicides can be a great help in preventing diseases when properly applied to the plant foliage. Since fungicides are preventive, they should be applied before the disease occurs, or as soon as the first symptoms of disease appear. Some vegetable diseases require specific fungi- cides for their control. An outline of diseases of specific vegetables, disease description, suggested cultural and chemical control and comments follows this section.
Fungicides are available primarily as wet- table powders, dry flowables and dusts, but a few are sold as emulsifiable concentrates, flowables and liquids. Wettable powders (WP) and dry flowable (DF) are formulated in such a manner as to be readily suspendable in water. Dusts (D) should not be mixed in water, but applied directly to the plant. Emulsifiable con- centrate (EC) fungicides contain an emulsifying agent that makes them readily suspendable in
water. Flowable (F) fungicides are finely ground wettable powders that are suspended in a liquid.
Some soil fungicides are available as gran- ules and are applied in the furrow at planting. Dust and spray fungicides may also be used as in-furrow treatments for seedling disease control.
Table II gives trade names and rates of broad spectrum fungicides for controlling foliar dis- eases of vegetables. Applying foliar fungicides to vegetables is best done by spraying, because it provides coverage of all plant surfaces. Foliar fungicides are available in dust formulations, but dusts are usually not as effective as sprays.

Never attempt to use dust formulations of fungi- cides in spray solutions. Dusts will not suspend in the spray solution. Wettable powder formula- tions may appear similar to dusts, but they are formulated to be suspended in spray solutions.
Foliar sprays will aid in controlling leaf spots, rusts, mildews, anthracnose and fruit rots. Foliar sprays are not effective against vascular wilts or root rots. Foliar sprays are protectants, because they form a protective layer of fungicide over the surface of the fruit and foliage. Disease agents (bacteria and fungi) that land on these fungicide-coated surfaces are killed or prevented from infecting the plant.
Most fungicides are not effective in inhibit- ing disease organisms once they have infected a plant. It is imperative that foliar fungicides be applied prior to infection of the plant. A spray schedule should be followed that maintains a protective fungicide layer on the foliage and fruit during favorable infection periods. By carefully monitoring their vegetables, some gardeners can usually delay the first fungicide
application until the first sign of disease. Then a 7-14 day spray schedule should be followed. During rainy or humid weather, spray applica- tion intervals should be shortened.
Proper pesticide mixing and spraying plays a very important part in achieving disease control. Most home gardeners will find a 1-2 gallon compressed-air sprayer adequate for applying foliar sprays. A nozzle with a cone pattern will provide the most effective coverage of plant foliage. Keep the pressure up to insure small spray particle size and good coverage.
Sprayers should be cleaned and rinsed after each use. Hose-end sprayers are not very effec- tive in applying fungicides to vegetables. Never use the same sprayer for fungicides and insecti- cides that has been used for herbicides. Residues of certain types of herbicides are very difficult to remove from sprayers. These residues may cause crop injury if a herbicide-contaminated sprayer is used in applying fungicides or insecticides.
Homeowners should protect themselves when mixing or applying pesticides. Always read the label for use directions and precaution statements.

 

Disease

 

Symptoms

Chemical & Formulation1 Approximate

Rate/Gallon2

 

PHI3

 

Limitations

 

ASPARAGUS

Root Rot

(Fusarium)

Deterioration of root system and poor growth of plants. Mancozeb 75 DF 1 TBSP   Pre-plant root dip.
Rust Numerous small, reddish- yellow spots on spears and ferns. Mancozeb 75 DF 2 TBSP 180 Apply to ferns after harvest of spears. Make applications at 7-10 day intervals, beginning at first appearance of disease.
 

BEAN (SNAP)

Anthracnose Brown spots on leaves, sunken with pinkish ooze. Basic copper sulfate 53WP

 

Chlorothalonil 54 F

mfg directions

 

 

3 tsp

0

 

 

7

Use western-grown seed. If plants become infected, do not work while plants are wet. Spray at weekly intervals. Do not plant beans in

field for at least two years following occurrence of disease. Plow infested bean trash deeply

into soil. Do not graze treated areas or feed treated plants to livestock.

Bacterial Blights Water-soaked spots on leaves and pods. Red margin and sometimes a yellow halo around spot. Fixed Copper mfg directions Same applies as for anthracnose.
Gray Mold (Botrytis) Gray moldy growth on pods and stems. Chlorothalonil 54 F 3 tsp 7 Begin at 25 to 50% bloom. Repeat at peak bloom. Do not graze treated areas or feed treated plants to livestock.
Mosaic Virus (bean yellow mosaic, bean common mosaic, and peanut stunt viruses) Yellowed leaves, with or without crinkling or speckling. Leaves cupped, runners killed.       Use resistant varieties. Half runners are most susceptible, particularly

“  Pink.’   Make successive plantings, as mosaic is more severe at certain times of the year.

Powdery Mildew White, powdery mold on surface of leaves. Sulfur Dust

 

Wettable Sulfur

mfg directions mfg directions 0

 

0

Use resistant varieties. Spray or dust with sulfur when disease first appears and repeat treatment 10 days later.
Root Rot & Seedling

Disease (Rhizoctonia)

Rots of seeds death of seedlings (damping off), and root rots. Terraclor 75 WP mfg directions   Apply Terraclor in-furrow at planting. Rotate crops, avoid double cropping beans and turn under plant debris well in advance of planting. (See Extension factsheet SP277-O)
Rust Reddish brown pustules develop on leaves. Chlorothalonil 54 F 3 tsp 7 Spray plants when rust appears and repeat at 7-10 day intervals. Do not graze treated areas or feed treated plant parts to livestock.
White Mold

(Sclerotinia)

White moldy growth on pods and stems. Terraclor 75 WP mfg directions   Spray at first appearance of disease.
 

Disease

 

Symptoms

Chemical & Formulation1 Approximate

Rate/Gallon2

 

PHI3

 

Limitations

 

BEAN (lima) AND BUTTER PEA

Stem Anthracnose Reddish brown spots on leaves and pods. Small black specks sometimes can be seen. Basic copper sulfate 53 W mfg directions Plant disease-free seed and rotate lima beans with other crops. Start applications of fungicide at first bloom and continue at 7-day intervals.
Root-knot Swollen, galled root system.       See section above on nematode control.
Root Rot         See Bean, Snap.
 

BEET

Downy Mildew Leaf

Spots

Various leaf spots. Fixed Copper mfg directions Spray at first appearance and repeat at 7-10 day intervals.
Rust Orange to rust colored spots that will rub off on hands. Sulfur mfg directions  
BROCCOLI (SEE CABBAGE)
BRUSSELS SPROUTS (SEE CABBAGE)
CABBAGE
Alternaria Leaf Spot Target spots on older leaves. Small, black spots may also occur. Chlorothalonil 54 F Maneb 80 WP 1.5 tsp

 

3-4 tsp

0

 

7

Start spraying when this disease first appears. Continue spray at 7-

10 day intervals until disease is under control. Remove excess residues by washing.

Downy Mildew Yellow areas on upper side of leaves; downy growth on lower surface.
Bacterial Soft Rot Soft, watery rot occurs, favored by hot, wet conditions. Begin in center of broccoli head.       Control of black rot will also help control bacterial soft rot. Avoid damage to the crop which will provide infection sites for soft rot bacteria.
Black Leg Lower stem turns brown and rots causing a canker.       Use certified disease-free seeds or transplants.
Black Rot Yellow V-shaped spots on edge of leaves. Veins near spots turn black.       Use certified disease-free seeds or transplants. Follow good sanitation practices. Don’t grow cabbage in locations where black rot occurred the previous year. See Extension factsheet SP277-P.
Club Root Galls or clubs on roots. Plants have light green color and are stunted. Hydrated lime

 

Terraclor 75 WP (transplant solution)

mfg directions

 

6 TBSP/gal. water

  Broadcast and work lime into soil by tilling within 3 days before planting. Apply 3/4 pint of Terraclor solution per plant as a transplant solution.
 

Disease

 

Symptoms

Chemical & Formulation1 Approximate

Rate/Gallon2

 

PHI3

 

Limitations

CABBAGE CONT’D
Damping-Off Young plants are rotted off at soil line. Terraclor 75 WP (seedbed drench) 1 TBSP/gal. water/50 sq. ft. seedbed   Sterilize seedbed soil. Apply

Terraclor drench after seeding.

Wire Stem Brown discoloration of stem. Entire stem becomes hard and constricted. Terraclor 75 WP 10-15 lbs./10,900 ft. of row   Sprayed as 8-inch band centered on row.
Yellows (Fusarium) Leaves turn yellow. Cross section of stem shows brown discoloration in veins.       Grow resistant varieties in areas where soil is infested. Secure disease-free transplants.
CANTALOUPE
Alternaria Leaf Spot Tan target spots on leaves, followed by blighting. Chlorothalonil 54 F Mancozeb 75 DF Maneb 80 WP 1.5-3 tsp

 

2-3 TBSP

 

4-6 tsp

0

 

5

 

5

Use disease-free seed. Fungicide applications can be delayed until first sign of disease if adequate survey of garden is maintained.
Anthracnose Sunken spots on fruit and tan leaf spots.
Downy Mildew Yellow, irregular spots on leaves.
Gummy Stem Blight Brown, round leaf spots. Cracks on stems with gummy ooze.
Bacterial Wilt Individual runners suddenly wilt and die.       Apply insecticide to control cucumber beetles, which spread the bacterium. See Extension factsheet SP277-C.
Powdery Mildew White, powdery mold on surface of leaves. Sulfur mfg directions Apply at first sign of disease and repeat at 7-14 day intervals. Do not apply sulfur if temperatures exceed

90 degrees F.

CAULIFLOWER (SEE CABBAGE)
CARROT
Alternaria Blight Numerous dark brown spots which may coalesce. Chlorothalonil 54 F 1.5-2 tsp Spray at first appearance and repeat at 7-10 day intervals. Alternaria blight can spread rapidly.
Cercospora Leaf Spot Small, dark brown to black spots on leaves.
Southern Blight White mycelial growth on lower stem; death of plant.       Use crop rotation.
 

Disease

 

Symptoms

Chemical & Formulation1 Approximate

Rate/Gallon2

 

PHI3

 

Limitations

COLLARD, KALE, MUSTARD & TURNIPS
Alternaria Leaf Spot Brown target spots on leaves. Fixed Copper

 

Maneb 80 WP

mfg directions

 

3-4 tsp

0

 

10

Maintain thin plant stand. Avoid low-lying or poorly-drained soils. Avoid hot part of growing season. Maneb for kale only. Begin sprays when disease is first noticed and repeat at 7-10 day intervals. Use a spreader-sticker for better fungicide coverage.
Anthracnose Small, tan spots with dark brown margins on leaves.
Cercospora Leaf Spot Tan leafspots with yellow haloes.
Downy Mildew Yellow spots on upper surface of leaf with white, downy growth on underside.
CORN (SWEET)
Blights (Helmintho- sporium) Spots on leaves and drying or blighting of leaves. Chlorothalonil 54 F Mancozeb 75 DF Maneb 80 WP 0.75-2 tsp

 

1.5 TBSP

 

3 tsp

14

 

7

 

7

Begin applications when conditions favor disease development and repeat at 4-7 day intervals. Do not apply chlorothalonil to sweet corn to be processed. Do not graze treated areas or feed treated plants to livestock. Use Maneb on crop

for seed production only.

Maize Dwarf Mosaic Alternating light and dark green streaks in leaves. Plants are stunted.       Plant early and preferably in fields not heavily infested with Johnsongrass. Silver Queen, a white variety, has fair tolerance to this disease.
Rust Bronze, elongate spots. Chlorothalonil 54 F Mancozeb 75 DF

Maneb 80 WP

0.75-2 tsp

 

1.5 TBSP

 

3 tsp

14

 

7

 

7

See “Blights.”
Stewart’s Wilt Brown streaks in leaves parallel to veins.       Control corn flea beetle. See insect section of this publication. Also called bacterial blight.
CUCUMBER
Alternaria Leaf Spot Brown, target spots on leaves. Chlorothalonil 54 F Mancozeb 75 DF Maneb 80 WP 1.5-3 tsp

 

2-3 TBSP

 

2-4 tsp

0

 

5

 

5

Use disease-free seed. Fungicide applications can be delayed until first sign of disease if an adequate survey of garden is maintained.
Anthracnose Brown, irregular spots on leaves, sunken spots on fruit.
Angular Leaf Spot Brown, angular spots on leaves. Fixed Copper mfg directions Spray at first appearance and repeat at 7-14 day intervals. Use disease- free seed. (Copper can injure young plants).
 

Disease

 

Symptoms

Chemical & Formulation1 Approximate

Rate/Gallon2

 

PHI3

 

Limitations

CUCUMBER  CONT’D
Downy Mildew Yellow, irregular spots on leaves. Chlorothalonil 54 F Mancozeb 75 DF Maneb 80 WP 1.5-3 tsp

 

2-3 TBSP

 

2-4 tsp

0

 

5

 

5

Use disease-free seed. Fungicide applications can be delayed until first sign of disease if an adequate survey of garden is maintained.
Gummy Stem Blight Brown, circular leaf spots. Cracks on stems with gummy ooze.
Bacterial Wilt Starts on individual

runners and eventually the entire plant wilts and dies.

      Apply insecticide to control cucumber beetles, which spread the disease. See Extension factsheet SP277-C and the insect control section of this publication.
Powdery Mildew White, powdery mold on surface of leaves. Sulfur mfg directions Apply at first sign of disease and repeat at 7-14 day intervals. Do not apply sulfur if temperatures exceed

90 F.

Scab Sunken spots on fruit. Chlorothalonil 54 F 2-3 tsp Resistant varieties widely available. Apply at first sign of disease and repeat at 7-10 day intervals.
EGGPLANT
Leaf Blights, Fruit Rots Spots develop on leaves and fruits. Fixed copper

 

Maneb 80 WP

mfg directions

 

3-4 tsp

0

 

0

Begin spraying before disease appears.
KALE (SEE COLLARD)
MUSTARD (SEE COLLARD)
OKRA
Pod Blight Young pods fail to develop and deteriorate.       Many times this blight is associated with poor pollination. The fungus Choanephora attacks the flowers

and young pods. Providing good air drainage will help prevent infection by Choanephora.

Root-knot Nematode Swollen, galled root system.       See section above on nematode control.
Verticillium Wilt Yellowing of leaves. Inside of stem will have brown discoloration.       Rotate okra with crops which are not susceptible to Verticillium wilt.
 

Disease

 

Symptoms

Chemical & Formulation1 Approximate

Rate/Gallon2

 

PHI3

 

Limitations

ONION
Downy Mildew Pale green, oval, sunken spots on leaves. Purplish mold may be in spots. Chlorothalonil 54 F Mancozeb 75 DF Maneb 80 WP 1.5-3 tsp

 

3 TBSP

 

2-6 tsp

14

 

7

 

7

Apply when disease first appears and repeat at 7-10 day intervals. Do not apply Mancozeb or Maneb on exposed bulbs. Do not apply Chlorothalonil within seven days of harvest on dry-bulb onions or

within 14 days on green onions, leeks or shallots. Do not apply Chlorothalonil to sweet Spanish onions.

Leaf Blast (Botrytis) White to tan streaks on leaves. Leaves eventually die.
Purple Blotch

(Alternaria)

Purple target spots on leaves.
PEA (SOUTHERN)
Cercospora

Leaf Spot

Light to dark brown spots on leaves. Chlorothalonil 54 F 1.5-2 tsp 42 Spray at early bloom and repeat at

7-10 day intervals. For use on beans harvested dry with pods removed (blackeye pea only). Only Bravo 720 or Bravo DG is labeled. Do not graze treated areas or feed treated plants to livestock.

Rust Bronze to rust-colored spots that will rub off on hand.
Mosaic Virus Mosaic of leaves (alternate light and dark green

areas). Distortion of leaves and pods.

      Use virus-free seed. Plant resistant varieties.
Powdery Mildew Dull white, felt-like growth on leaves. Sulfur mfg directions Spray at first appearance at 7-10 day intervals.
Root Rot Brick-red lesions on lower stem and roots. Roots later die.       See Bean, Snap.
PEPPER
Bacterial Spot Black, angular spots appear on leaves. Dark raised spots also occur on fruits. Plants shed infected leaves. Fixed Copper

Plus

Maneb 80 WP

mfg directions mfg directions Use disease-free seed or buy disease-free transplants. Spraying with fixed copper will help prevent spread.
Blossom-end Rot Tan sunken areas on blossom end and side of fruit.       Lime soil to provide adequate calcium. Avoid planting on droughty soils. Do not use excessive nitrate fertilizer. Irrigate and follow culture practices that tend to provide the most uniform soil moisture.
Cercospora

Leaf Spot

Circular spots with gray centers develop on leaves. Fixed copper

 

Maneb 80 WP

mfg directions

 

3-6 tsp

0

 

7

Apply fungicide when disease appears and continue as needed on a 7-10 day schedule.
Anthracnose Sunken spots on ripening fruit.
 

Disease

 

Symptoms

Chemical & Formulation1 Approximate

Rate/Gallon2

 

PHI3

 

Limitations

PEPPER CONT’D
Phytophthora Blight Rapid wilt and death of plants in wet areas of field.       Plant on raised bed.
Root-knot Swollen, galled root system.       See previous section on nematode control.
Southern Blight Plants wilt and die. White mold can often be seen on base of stem. Terraclor 75 WP (soil treatment) mfg directions   Turn soil deep to bury plant debris that might harbor disease organism. Use Terraclor in setting water at planting. Rotate with sod crops.
Sun Scald Dry, white bleached spot on side of pod exposed to sun.       Fruits on plants kept in a healthy, vigorous condition are not likely to be injured by sun scald. Control of bacterial spot will prevent loss of leaves and keep the fruit protected from the sun.
POTATO, IRISH
Early Blight Small brown, target spots appear on leaves in hot, wet weather. Chlorothalonil 54 F Mancozeb 75 DF Maneb 80 WP 1-1.5 tsp

 

1-2 TBSP

 

3-4 tsp

0

 

14

 

14

Start applications when plants are

4-6 inches high and continue at 7-

10 day intervals.

Late Blight Water-soaked irregular spots on leaves in cool,

wet weather. Plants appear scalded.

Black Leg Stem turns black. Plant wilts and dies.       Plant certified seed.
Rhizoctonia Canker

(Black Scurf)

Black cankers girdle stem, causing poor growth. Terraclor 75 WP mfg directions    
Scab Rough, scabby spots on tubers.       Use disease-free seed. Where soil is infested with scab organism, use resistant varieties and rotate crops. See SP277-G.
Seed Piece Decay Rotting of seed piece. Mancozeb

 

Maneb

Use dust formulations according to mfg directions   Treat seed pieces with fungicide dust before planting. Plant seed pieces immediately after treating. Do not use treated seed pieces for food, feed or oil purposes.
Ring Rot Brown discoloration of vascular tissue in tuber.       Plant certified disease-free seed and practice crop rotation.
Virus Diseases Curling, streaking, or mosaic in leaves. Plants may be stunted.       Plant certified disease-free seed and practice crop rotation.
 

Disease

 

Symptoms

Chemical & Formulation1 Approximate

Rate/Gallon2

 

PHI3

 

Limitations

PUMPKIN
Downy Mildew Yellow, irregular spots on leaves. Chlorothalonil 54 F Maneb 80 WP 1.5-3 tsp

 

3-4 tsp

0

 

5

Begin spraying at first sign of disease. See label for spray intervals. Use higher rates for scab control.
Gummy Stem Blight Black, circular spots on fruit.
Microdochium Blight White dashes on stem surface.
Scab Sunken or raised spots on fruit.
Mosaic Virus Green patterns on fruit.       Reflective mulches, aphid control, and weed control may be helpful. Control is difficult.
Powdery Mildew White, powdery mold on leaf surface. Sulfur mfg directions Begin spraying at first sign of disease.
SPINACH
Downy Mildew (Blue

Mold)

Yellow spots on upper leaf surface. Gray downy

fungus on underside of leaf.

Basic copper sulfate 53 WP mfg directions Start fungicide applications at first sign of disease and continue at 7-10 day intervals as necessary. Where white rust has been a problem in

the past, spraying should start when the first true leaves develop. “Fall Green,” a fall variety, is moderately resistant to white rust and several races of blue mold.

White Rust Yellow spots on upper leaf surface. White powdery mass on underside of leaf.
SQUASH
Downy Mildew Yellow, irregular spots on leaves. Chlorothalonil 54 F Mancozeb 75 DF

Maneb 80 WP

1.5-3 tsp

 

2-3 TBSP

 

3-4 tsp

0

 

5

 

5

Begin spraying at first sign of disease. See label for spray intervals.
Powdery Mildew White, powdery mold on leaf surfaces. sulfur mfg directions Apply at first sign of disease and repeat at 7-14 day intervals. Do not apply sulfur if temperatures exceed

90 F.

Scab Sunken or raised spots on fruit. Chlorothalonil 54 F 2-3 tsp Begin spraying at first sign of disease. See label for spray intervals.
Blossom Blight Blossoms rot and stick to young fruit. The end of the fruit turns black.       Provide good air circulation for rapid drying.
Mosaic Virus Greening of fruit. Leaves mottled, veins stunted.       Reflective mulches may be of some value. The yellow-stemmed

varieties Multipik, Superpik and Supersett are tolerant of watermelon mosaic virus.

 

Disease

 

Symptoms

Chemical  & Formulation1 Approximate

Rate/Gallon2

 

PHI3

 

Limitations

SWEET  POTATO
Black Rot Black spot on roots. Dry, black decay extends in flesh of root.       Use certified  seed. Do not replant for 3 years in locations  where this disease has been present.
Scurf Brownish  black discoloration  on surface of potato.
Cork Small, black, corky spots in potatoes.  Spots do not extend to surface.       Use certified,  disease-free  seed.
Root-knot  Nematodes Longitudinal  cracking  of potato.       See previous section on nematode control.
Soil Rot (Pox) Circular  sunken areas on fleshy roots. Feeder roots are blackened.       Rotate sweet potatoes  with other crops. Maintain  pH below 5.2 in infested fields. Grow a resistant variety.
Stem Rot (Fusarium

Wilt)

Plants are yellow and stunted. The interior of the vine shows a brown discoloration.       Select disease-free  seed stock by examining  vines of each hill. If cross section of vine shows a brown discoloration,  do not use roots for seed stock.
Southern  Blight (Plant

Bed)

Plants die in spots in bed. White growth on lower stem.       Use new soil in beds each year.
TOMATO
Bacterial  Spot Small, raised spots on fruits. Water-soaked spots on foliage. Fixed Copper plus

Mancozeb  75 DF OR plus

Maneb 80 WP

mfg directions

 

1.5-2 TBSP

 

3-4 tsp

0

 

5

 

5

Use hot water seed treatment  or use disease-free  seed.
Blossom-End  Rot Black spot on blossom end of small green fruit.       Maintain  adequate  calcium  level in soil and uniform soil moisture. Plant least susceptible  varieties. Avoid droughty  soils.
Early Blight Brown target spots followed  by blighting  of foliage. Chlorothalonil 54 F Mancozeb  75 DF Maneb 80 WP 1.5-2 tsp

 

1.5-3 TBSP

 

3-6 tsp

0

 

5

 

5

Start preventative  spraying as soon as plants are established  in the garden. Spray at 7-10 day intervals. During periods favorable  for

disease development,  shorten the spray interval.  Maneb 80 WP can be used in the greenhouse  and in the garden.

Anthracnose Circular,  sunken spots on ripe fruit.
Septoria  Leaf Spot Small, gay circular leaf spots with dark borders.
Buckeye  Fruit Rot Circular,  zonate bands within large spot on fruit, worse on lower clusters.       Mulch and stake plants to keep soil off fruit clusters.
 

Disease

 

Symptoms

Chemical & Formulation1 Approximate

Rate/Gallon2

 

PHI3

 

Limitations

TOMATO CONT’D
Fusarium Wilt Yellowing and wilting of foliage. Inside of stem has brown discoloration.       Use a resistant variety and rotate tomato fields. Obtain disease-free plants and plant on disease-free soil.
Gray Mold (Botrytis) Leaves turn brown from tip back; gray mold can be

seen on foliage during humid weather.

Chlorothalonil 54 F 3 tsp Begin fungicide spray applications at first sign of disease.
Late Blight Irregular, watersoaked spots on leaves. Occurs in mold, wet weather. Chlorothalonil 54 F Mancozeb 75 DF

Maneb 80 WP

1.5-3 tsp

 

1.5-3 TBSP

 

2-6 tsp

0

 

5

 

5

Follow spray schedule for early blight. If weather conditions are favorable for late blight, shorten spray interval. Obtain disease-free plants and plant in non-infested soil.
Leaf Mold Yellow spots on upper surface of leaves. Olive to gray mold on underside of leaves. Primarily in greenhouses. Chlorothalonil 54 F 1.5-2 tsp Fungicides will control leaf mold in the garden, but are not adequate in greenhouse production. The best control in greenhouse tomatoes is the

use of resistant varieties and regulation of humidity.

Pythium Stem Rot Dark, water rot of lower stem of young plants.        
Southern Blight Plants wilt and die. White mold can often be seen on base of stem. Terraclor 75 WP (soil treatment) mfg directions   Turn soil deep to bury plant debris which might harbor disease organisms. Use Terraclor in setting water. Rotate with turf.
Verticillium Wilt Yellowing of leaves; inside of stems will have brown discoloration.       Use resistant varieties. Practice long rotations of tomatoes with other crops.
TURNIP (SEE COLLARDS)
WATERMELON
Alternaria Leaf Spot Brown, target spots on leaves. Chlorothalonil 54 F Mancozeb 75 DF Maneb 80 WP 1.5-3 tsp

 

2-3 TBSP

 

2-4 tsp

0

 

5

 

5

Begin at first sign of disease. See label for spray intervals. Plant anthracnose- resistant varieties. Mancozeb and Maneb are not labeled for scab control.
Anthracnose Brown irregular spots on leaves and sunken spots on fruit.
Cercospora Leaf Spot Tiny, dark brown spots.
Downy Mildew Yellow, irregular spots on leaves.
Gummy Stem Blight Irregularly circular leaf spots. Cracks on stems with gummy ooze.
Scab Small, raised warts on fruit.        
Fusarium Wilt Yellow and wilting of leaves. Brown discoloration in interior of vine.       Grow resistant varieties. Long rotations should be practiced even where

resistant varieties are used.

Table II. Common Names and Trade Names of  Chemicals for Controlling Diseases of  Vegetables

 

Common Names

 

Trade Names1

 

benomyl

 

Note:  Home  garden benomyl products are  no longer available.

chlorothalonil Bravo 720  (54%) Bravo 75 WP Bravo 90 WDG

Bravo Flowable Fungicide

Broad Spectrum Liquid Fungicide

Fungi-Gard

Lawn, Ornamental and  Vegetable Fungicide

Vegetable Disease Control

fixed  coppers Basicop Blue Shield Kocide

Tri-Basic Copper  Sulfate

mancozeb2 Dithane DF Manzate 200  DF Penncozeb
maneb2 Maneb 80 WP Maneb Spray

Maneb Liquid Fungicide

PCNB Terraclor 10 G Terraclor 75 WP

 

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