Cucumber, Muskmelon Diseases
Cucumber, Muskmelon Diseases
Angular Leaf Spot
Angular, light brown spots form on the leaves. The center of the spot drops out leaving a ragged hole. On fruit, gray, water soaked spots form. The spots crack and produce a crusty, tan to white lesion. Often an amber colored ooze comes from the spot. The disease is favored by humid weather, temperatures between 70 and 80 degrees, and by mechanical or insect injury. The bacteria are spread by wind, splashing water and insects. Use copper(0 to 1) dust or spray.
Scab produces irregular spots on the leaves and stems. The spots have yellow margins and brown centers. The center drops out leaving a ragged hole. Water soaked spots form on the fruit and an amber colored ooze is seen on the spots. The fruit spots become dark gray to black and are sunken. The disease is favored by humid, wet weather and temperatures between 60 and 80 degrees. The disease is spread by tools, wind, splashing water, and insects. Scab may be controlled with sprays of Chlorothalonil(0) or copper(1).
Round watersoaked leaf spots go from yellow to brown and have red margins. The center drops out giving a shothole appearance. Often defoliation occurs. On fruit, circular, dark brown to black sunken lesions form with pinkish-orange spore masses in the center. The disease is favored by humid wet weather and temperatures between 60 to 80 degrees. The disease is spread by tools, wind, splashing water, and insects. Use copper(1) dust or spray or Chlorothalonil(0).
Alternaria Leaf Spot
Circular, tan spots with a concentric ring pattern form on the leaves. Defoliation will occur. The disease is favored by bright sunshine, frequent dews or showers, and temperatures between 60 and 90 degrees. The disease is spread by tools, wind, splashing water and insects. Use sulfur dust(5).
Leaves turn dull green, then leaves, branches and finally the whole plant wilt and die. When the stem is cut and squeezed a sticky, stringy ooze comes out. The disease is spread by cucumber beetles. Cucumber beetle migration and feeding is favored by dry weather. The disease is favored by temperatures between 50 and 70 degrees and frequent dews. prevent its occurrence by controlling the beetles.
Powdery mildew causes a white powdery growth on leaves and stems. Infected parts turn yellow, shrivel and plants are defoliated prematurely. Yield is reduced and fruit quality is poor. The disease is favored by humid weather with frequent dew and temperatures between 70 and 90 degrees. Use Copper(0 to 1) spray or dust, sulfur (5) dust, or Chlorothalonil sprays.
Mosaic causes mottled dark and light green, crinkled leaves. The disease is more noticeable on young leaves. Old leaves have V shaped dead areas extending from the leaf margins to the middle vein. The fruit are mottled, warty and misshapen. The disease is favored by poor weed control, as many weeds act as a host to the virus. The disease is spread by aphids and cucumber beetles. There is no chemical control.