Disease Control

NOTE: For the disease control products listed below, one product trade name and formulation is provided for each active ingredient (common name) as an example of rates, preharvest interval (PHI), restricted entry interval (REI), and special instructions. In many cases, there are other products available with the same active ingredient. Please see Table 28 and Fungicides and Bactericides Alphabetical Listing by Trade Name for more information on products with the same active ingredients.

The symbol OG   indicates a product is listed by the Organic Materials Review Institute (OMRI) as approved for use in organic production. See Organic Certification section for more details.

Anthracnose (Colletotrichum lindemuthianum)

Anthracnose is common in beans and is primarily a seed-borne disease surviving on dry, undecomposed residues for up to 5 years. Symptoms begin as red spots on leaves and pods that develop into black lesions. Leaf veins can turn red-brown. Start with certified, disease-free seed and use resistant cultivars. Fungicides may be applied as seed treatments or foliar sprays.

azoxystrobin (Quadris): 6.2 to 15.5 fl oz/A; PHI 0d, REI 4h, Group 11.

azoxystrobin plus chlorothalonil (Quadris Opti): 1.6 to 2.4 pt/A; PHI 14d, REI 12h, Groups 11 & M5. DRY bean only. See label for tank mix precautions.  

azoxystrobin plus propiconazole (Quilt): 14 fl oz/A; PHI 7d succulent; PHI 14d dry, REI 12h, Groups 11 & 3.

chlorothalonil (Bravo Weather Stik): 1.375 to 3.0 pt/A; PHI 7d (snap) to 14d (dry), REI 12h, Group M5.

fluxapyroxad plus pyraclostrobin (Priaxor): 4.0 to 8.0 fl oz/A; PHI 7d, REI 12 h, Groups 7 & 11.

penthiopyrad (Fontelis): 14.0 to 30.0 fl oz/A; PHI 0d, REI 12h, Group 7.

potassium bicarbonate (MilStopOG): 2.5 lb/100 gal; PHI 1d, REI 4h.

propiconazole (Tilt): 4.0 fl oz/A; PHI 7d, REI 12h, Group 3.

pyraclostrobin (Headline): 6.0 to 9.0 fl oz/A; PHI 7d (succulent) to 21d (dry), REI 12h, Group 11. Apply at the beginning of flowering. Do not make more than 2 applications/season or alternate with other Group 11 fungicides.

thiophanate-methyl (Topsin 4.5 FL): 30 to 40 fl oz/A; PHI 14d (snap) to 28d (dry), REI 24h (succulent); 72h (dry), Group 1.

Downy Mildew-Lima Beans (Phytophthora phaseoli)

Downy mildew resistant lima bean varieties are available. Rotate to non-susceptible crops. Apply seed treatments to protect germinating seedlings against soil-borne inoculum. Plow under infected debris in fall. Rotate with crops other than beans for two years.

chlorothalonil (Bravo Weather Stik): 1.375 to 3.0 pt/A; PHI 7d (snap) to 14d (dry), REI 12h, Group M5.

copper hydroxide (Kocide 3000): 0.5-1.25 lb/A; PHI 0d, REI 48h, Group M1. Do not apply in a spray solution having a pH less than 6.5 or tank mix with Aliette.

cyazofamid (Ranman): Succulent beans ONLY. 2.75 fl oz/A; PHI 0d, REI 12h, Group 21. Tank mix with organosilicone or non-ionic surfactant.

mefenoxam (Apron XL): 1.28 fl oz/100 lb seed; REI 48h, Group 4. Seed treatment.

phosphorous acid  (Fosphite): 1.0 to 3.0 qt/100 gal; PHI 0d, REI 4h, Group 33. Do not apply to heat or moisture stressed crops or plants recently treated with copper.

potassium bicarbonate (MilStopOG): 2.5 lb/100 gal; PHI 1d, REI 4h.

pyraclostrobin (Headline): 6.0 to 9.0 fl oz/A; PHI 7d (succulent) to 21d (dry), REI 12h, Group 11. Do not make more than 2 applications before alternating to a non-Group 11 fungicide.

Rhizoctonia solani

Rhizoctonia stem canker caused by strains of the soil-borne fungus Rhizoctonia solani is common throughout the world on peas and beans. The pathogen survives between crop seasons as sclerotia (survival structures), mycelium in the soil, or on or in infected plant debris.  It is spread in infested soil or plant debris by wind, rain, irrigation water, and machinery. When a soil becomes infested, it remains so indefinitely. Seedlings and young plants are highly susceptible to infection and disease severity is increased by low soil temperatures and compaction. Seed decay and damping off can be controlled by using high-quality seed, with high germination and vigor,  and by practices that encourage rapid germination and emergence.  Seed treatments are not effective against infections later in the season. The disease may be reduced by sowing seed as shallowly as possible in warm, moist soil. Land preparation that minimizes soil compaction and structural damage will lessen disease severity. Rotate crops with a cereal or pasture crop (avoid beets, beans, Brassicas and potatoes which increase inoculum). Cover crops and other practices that increase organic matter and improve soil structure are recommended. Some brassica crops (mustard, rape) used as green manure have been reported to be disease suppressive. Avoid incorporating green manure immediately before planting or damaging roots by shallow cultivation. Fungicides can manage Rhizoctonia root rot on young seedlings if applied as a seed treatment or soil drench.

Bacillus amyloliquefaciens F727 (StargusOG): 2 to 4 qt/A; PHI 0d, REI 4h, Group 44. Apply preventatively in a minimum of 50 gallons of water/A.

fludioxonil (Maxim 4FS): 0.08 to 0.16 oz/100 lb seed; REI 12h, Group 12. For protection against seed-borne and soil-borne fungi.

PCNB (Blocker 4F): 2.3 to 3.3 fl oz/1,000 ft.; REI 12h, Group 14.

Trichoderma asperellum, T. gamsii (BiotamOG): See label for in-furrow, drench, and broadcast rates; PHI 0d, REI 4h, Group NC.

thiram (Thiram 42-S): 2.0 fl/oz./100 lb seed; REI 12h, Group M3.

Rust (Uromyces appendiculatus)

Symptoms are most visible on the undersides of leaves. Symptoms begin as tiny white raised spots called pustules that break open to produce distinct red spots with dust-like spores (uridiniospores) which easily brush off. Spots may be surrounded by yellow halos in some varieties. Severely infested leaves fall off plants. Overwintering spores (teliospores) are black in color. Plant resistant varieties. Plow under crop debris immediately after harvest. Bury or otherwise destroy crop residues to reduce overwintering inoculum. Rotate away from beans for 2 years or up to 5 years in reduced tillage. Avoid overfertilization with high levels of nitrogen, but ensure adequate potassium. Disinfect poles in production of pole beans. Avoid long periods of leaf wetness when irrigating during times when temperatures are warm. 

azoxystrobin (Quadris): 6.0 fl oz/A; PHI 0d, REI 4h, Group 11. 

azoxystrobin plus chlorothalonil (Quadris Opti): 1.6 to 2.4 pt/A; PHI 14d, REI 12h, Groups 11 & M5. DRY bean only. See label for tank mix precautions. Not labeled for soybean. 

azoxystrobin plus propiconazole (Quilt): 14 fl oz/A; PHI 7d succulent; PHI 14d dry, REI 12h, Groups 11 & 3.

Bacillus amyloliquefaciens strain D747 (DoubleNickelOG): 0.25 to 3.0 lb/A; PHI 0d, REI 4 h, Group 44. Disease suppression only. For improved control; mix or rotate with a chemical fungicide.

chlorothalonil (Bravo Weather Stik): 1.375 to 3.0 pt/A; PHI 7d (snap) to 14d (dry), REI 12h, Group M5.

myclobutanil (Rally): 4.0 to 5.0 oz/A; PHI 0d, REI 24h, Group 3. Observe a 30-day plant back interval. Snap beans only.

penthiopyrad (Fontelis): 14.0 to 30.0 fl oz/A; PHI 0d, REI 12h, Group 7.

polyoxin D (OSO 5% SC): 3.75 to 13.0 fl oz/A; PHI 0d, REI 4h, Group 19.

propiconazole (Tilt): 4.0 fl oz/A; PHI 7d, REI 12h, Group 3. 

pyraclostrobin (Headline): 6.0 to 9.0 fl oz/A; PHI 7d (snap) to 21d (dry), REI 12h, Group 11.  Do not make more than 2 applications per season or rotate with another Group 11 fungicide.

sulfur (Microthiol DisperssOG): 3.0 to 10.0 lb/A; PHI 0d, REI 24h, Group M2.

Seed Decay

Buy treated seed. Do not use treated seed for food or feed.

Bacillus amyloliquefaciens strain D747 (DoubleNickelOG): 0.12 to1.0 lb/A as a soil drench; PHI 0d, REI 4 h, Group 44.

fludioxonil (Maxim 4FS): 0.08 to 0.16 oz/100 lb seed; REI 12h, Group 12. For protection against seed-borne and soil-borne fungi.

mefenoxam (Apron XL): 0.16 to 0.64 fl oz/100 lb seed; REI 48h, Group 4. For Pythium damping off. Early season Phytophthora  protection (0.64 fl oz/lb seed).

thiram (Thiram 42-S): 3.0 lb (lima) 2.0 lb (snap & dry)/100 lb seed; REI 12h, Group M3.

White Mold (Sclerotinia sclerotiorum)

Space plants to allow good air circulation. Plant on well-drained soil. Sclerotinia produces sclerotia, which are hard, black structures from 1/16" to 1/2" in length, inside or on the surface of infected tissue. Sclerotia can survive for years in the soil and are responsible for initiating disease. Germination of sclerotia and initiation of disease are dependent on prevailing weather conditions. Optimum temperature for sclerotia to germinate is about 52°F but some sclerotia germinate over a wider range of temperatures. Germination is also dependent on continuous soil wetness for 10 days.

Many vegetable crops and weeds are susceptible to this fungus; corn and grasses are not. Lettuce, cabbage, tomato, carrot, brassicas and snap beans are among the most susceptible and should not be grown on land known to be contaminated with Sclerotinia. After an episode of disease, rotate away from susceptible crops for 7 years. A single infected head of cabbage may produce more than 1,000 sclerotia. Removal of diseased plant material as soon as possible is highly is recommended.

Bacillus amyloliquefaciens F727 (StargusOG): 2.0 to 4.0 qt/A; PHI 0d, REI 4h, Group 44. Apply preventatively in a minimum of 50 gallons of water/A.

boscalid (Endura): 8.0 to 11.0 oz/A; PHI 7d (succulent) to 21d (dry), REI 12h, Group 7. Do not make more than 2 applications per season.

cyprodinil plus fludioxonil (Switch 6.25 WG): 11.0 to 14.0 oz/A; PHI 7d, REI 12h, Groups 9 & 12.

Coniothyrium minitans (Contans WG): Apply 1.0 to 4.0 lb/A in 20 to 50 gal water; REI 4h, Group is not applicable. Spray on the soil surface and incorporate into the top 2" of soil. Fall application is best or 3 to 4 months before planting to allow for the biocontrol agent to infect the sclerotia of Sclerotinia. OMRI listed.

fluazinam (Omega 500F): 0.5 to 0.85 pt/A; PHI 14d edible pod, PHI 30d dry and lima beans, REI 72h, Group 29.

iprodione (Rovral 4F): 1.5 to 2.0 pt/A; PHI 14d, REI 24h, Group 2. See label for restrictions.

PCNB (Blocker 4F): 2.2-3.3 fl oz/1,000 ft.; REI 12h, Group 14.

penthiopyrad (Fontelis): 16.0 to 30.0 fl oz/A; PHI 0d, REI 12h, Group 7.

polyoxin D (OSO 5% SC): 3.75 to 13.0 fl oz/A; PHI 0d, REI 4h, Group 19.

thiophanate-methyl (Topsin 4.5 FL): 20 to 30 oz/A; PHI 14d snap or lima and 28d dry, REI 24h (succulent) and 72h (dry), Group 1.

Trichoderma asperellum, T. gamsii (BiotenOG): See label for in-furrow, drench, and broadcast rates; REI 1h, Group NC.

Bacterial Diseases (Pseudomonas spp. and Xanthomonas spp.)

Bacterial leaf diseases include: bacterial bean blight (Xanthomonas campestris pv. phaseoli), bacterial brown spot (Pseudomonas syringae pv. syringae), and halo blight (Pseudomonas syringae pv. phaseolicola). Plant western-grown, disease-free seed. Eliminate wild cherries and lilacs near bean fields. Do not cultivate or harvest when plants are wet. Use a 2-year rotation. Plow under infected debris in fall.

copper hydroxide (Kocide 3000): 0.5 to 1.25 lb/A; PHI 0d, REI 48h, Group M1. Do not apply with a spray solution having a pH less than 6.5 or tank mix with Aliette.

Bean Common Mosaic Virus (BCMV)

In addition to mosaic and lesions of the foliage, BCMV can also cause blackened roots. Several different strains of the virus are recognized; the symptoms and host ranges vary according to the strain. The virus can be seed-borne and is transmitted by at least 12 species of aphids in a nonpersistent manner. Resistant varieties are available and constitute the most reliable means of control. Seed treatment, insecticides, and roguing of diseased plants are of little value.

Bean Yellow Mosaic Virus (BYMV)

Many strains of this virus are known. Symptoms of BYMV are easily confused with BCMV. However, BYMV is not seed-borne and unlike BCMV, BYMV is spread in a persistent manner by more than 20 species of aphids. Entire plantings may become infected, resulting in substantial losses in yield. Disease outbreaks are often correlated with the presence of virus-source plants such as sweet clover, white clover, crimson clover, and Gladiolus sp. Since the virus overwinters in legumes such as clover and vetch, beans should be planted at least 800' away. Insecticides applied early will reduce spread. Plant mosaic resistant varieties (see varieties list).