| Disease (causal agent) | Symptoms | Survival of pathogen and effect of environment | Comments on control |
|---|---|---|---|
| Bacterial gall (Pantoea agglomerans (formerly Erwinia herbicola)) |
Soft, light brown galls up to 2 inches (5 cm) in diameter develop at or below soil line. Galled plants are often stunted and some die. | Bacteria survive in galls and in aerial parts of the plant. Infection is favored by warm conditions. | Use pathogen-free stock developed through tissue culture. Avoid wounding plants when establishing field plantings. Maintain strict sanitation in propagation. |
| Flower blight (Alternaria sp.) |
Infected flowers turn black. | Favored by moist conditions. | Avoid overhead irrigation during flowering. Protective sprays of iprodione or chlorothalonil may be helpful in severe situations. |
| Phytophthora crown rot * (Phytophthora parasitica) |
Leaves wilt and turn light green. Entire plant may collapse and die. Crown tissue is discolored and a soft, wet decay develops. Secondary bacteria cause the diseased tissue to putrefy. | Pathogen is soilborne and may be present in many fields. Disease is favored by warm temperatures 90°F, moist conditions, and poor drainage. | Improve drainage by planting on raised beds. Do not moisture-stress plants, but do not overwater. Soil drenches of oomycete (water mold) specific fungicide are helpful in preventing the disease. |
| Root rot * (Pythium spp.) |
Soft wet decay of seedlings and plants in propagation. Leaves of infected plants turn grey-green. In the field, roots are rotted and plants are stunted. | Several species of Pythium are involved. Pythium aphanidermatum is favored by warm or hot conditions while P. ultimum develops at lower temperatures. Both pathogens are present in many field soils. Disease is favored by overwatering and poor drainage. | An oomycete (water mold) specific fungicide is helpful when used in preventative programs. |
| Stem rot (Rhizoctonia solani) |
All stages of growth may be affected. Stems are infected at or just beneath the soil line. Sunken dark lesions are dry in the early stages but later the decay becomes soft and wet. | Fungus occurs naturally in many soils. Favored by warm, wet conditions and deep planting. | Treat soil or planting medium with granular PCNB before planting. Avoid deep planting. Spray base of plants before or after planting with iprodione or PCNB. Keep PCNB off foliage. |
| Gypsophila is also susceptible to gray mold * (Botrytis cinerea), bacterial fasciation (Rhodococcus fascians), root knot nematode** (Meloidogyne spp.), cottony rot * (Sclerotinia sclerotiorum), southern blight * (Sclerotium rolfsii), crown gall * (Agrobacterium tumefaciens), and aster yellows * (Aster yellows phytoplasma). | |||
| * For additional information, see section on Key Diseases. |
| ** For additional information, see section on Nematodes. |