This week I decided to cover two problems that are running rampant through customers' landscapes. We have covered them in detail before, so no need to do that again. I am just going to review how they are causing damage to certain plants and what to do about it.
TWO CURRENT GARDEN PROBLEMS
Powdery Mildew on Cucumbers (Squash, Melons, and Pumpkins as well):
The upper surfaces of cucumber leaves are covered with a white powdery growth. The leaves and stems turn brown as the fungus takes nutrients from the plant. Eventually the leaves wither and the plant dies.
The white fungal strands of the disease are spread by the wind and can take over a patch quickly. It can thrive in both humid and dry weather.
If possible, remove badly infected leaves. This will not only cut down on the amount of fungal strands that are available to spread, it will also allow more air to flow through the plants. Avoid any overhead watering. Spray with Copper, Sulfur, or Serenade every 7 days as long as the disease is a problem. They are all organic fungicides.
Budworm on Geraniums and Petunias.
These budworms come from a moth. They love geraniums and petunias! Their presence is always noted by the black droppings they produce.
Damage is concentrated on the flower buds. At first they "bud tunnel" through the buds creating little holes. Later they consume the entire bud and petals. The result is a reduced flower production and deformed flowers. When all the flowers have been eaten, budworms will start to chew on the leaves.
The worst damage in northern states occurs during August and early September. Usually there are two generations per year.
Control budworms by spraying with organic Thuricide (BT Spray) or Pyrethrin every 7 to 10 days.