East Bay Nursery
The Bay Area's Place for Plants
2332 San Pablo Ave, Berkeley, CA 94702
510.845.6490
Open: Tues - Sat 8:30-5:00; Closed Sun & Mon
2332 San Pablo Ave, Berkeley, CA 94702
510.845.6490
Open: Tues - Sat 8:30-5:00; Closed Sun & Mon
 
 

Common Diseases

These are the most common diseases our customers ask for assistance with. If you can not identify your problem from this page please bring a sample to us. Include pieces of damaged leaves, stems, and/or flowers.

We find the I.P.M. (Integrated Pest Management) site from UC Davis very useful as well.

Powdery Mildew

Powdery Mildew is caused by several different fungi. The white, sometimes cottony growth attacks most any part of a plant under both humid and dry conditions. It can cause disfiguring to the leaves and flowers, defoliation, and in uncontrolled situations, prolonged infection can cause death in some plants. Spores are carried into the garden by wind and can grow on most any plant they land on. Good garden hygiene and proper plant culture can reduce the chances of infection in your garden

Controls:

Remove all infected material from the garden. Do not put clippings in the compost. You can control powdery mildew with a variety of materials. Neem Oil, sulfur and copper are common controls that have very little impact on the environment. They control the spread of the mycelium of the fungi by affecting the pH of the leaf surface. We also carry Serenade which is a bacterial control (a strain of Bacillus subtilis) of many garden and lawn diseases. Serenade’s bacteria controls diseases by actually eating the mycelium and fruiting bodies preventing the disease from spreading. Chemical sprays that directly control the fungi are available. We have found controlling powdery mildew is easier to achieve by varying the products used with each application.

Rust

Rust looks just as it sounds, orange to yellow orange fungal growth typically on the leaves and stems of many plants. When mature, orange, dust like spores are produced. These spores spread through the garden by wind, are carried by insects, or fall on other plants where growth can then begin again. Other signs of infection can include irregular patches of yellowing tissue with either orange or brown centers or mottling of the leaf. Favorable conditions for most rusts are; high humidity and temperatures between 55-75 degrees.

Controls:

Control with applications of copper or sulfur containing fungicides through the period when the conditions are favorable for fungal growth. Remove any infected part of the plant and discard all clippings and debris collected from around the plant. Sulfur and copper are two common controls that have very little impact on the environment. They control the spread of the mycelium of the fungi by affecting the pH of the leaf surface. We also carry Serenade which is a bacterial control (a strain of Bacillus subtilis) of many garden and lawn diseases. Serenade’s bacteria controls diseases by actually eating the mycelium and fruiting bodies preventing the disease from spreading. Chemical sprays that directly control the fungi are available. We have found controlling rust is easier to achieve by varying the products used with each application.

Sooty Mold

This is one of several types of fungi that grow and feed on the sugary excretions left on the surfaces of plants by several types of sucking insects, such as, Aphids, Mealy Bugs, Scale, Thrips, and Whiteflies. This mold does not attack the plant directly but can threaten the health of the plant by inhibiting light from reaching the leaf surface, which, in turn, stops photosynthesis. Without being able to photosynthesis the plant will die.

Controls:

These insects are easier to prevent than control. On occasion, spray down the foliage of the shrubs and small trees in your garden with a stream of water. This will keep the plant free from dirt, dust, and control exploding populations. If you have an insect infestation use Insecticidal Soap, Horticultural Oil, or Neem Oil for organic control. The sooty Mold will disappear when the insect population is controlled.

Gummosis or Bacterial Canker

This bacteria attacks trees that produce stone fruit, such as, cherries, apricot, plums, peaches, and nectarines. Sunken areas of soft tissue form along branches and on the trunk. These areas ooze thick, amber colored, sour smelling gum in fall, winter, and spring. Some of these trees will naturally ooze this same gum from cracks in the bark which occur during years with severe weather; this is a natural thing for the plant and treatment is not necessary. The difference between natural gum and bacterial gum is the smell. The bacterial gum will have a distinct sour smell where the natural gum will not have a fragrance or be slightly sweet smelling.

Controls:

Bacterial canker is difficult to control. Clean out infected lesions along the trunk and main branches. Be sure to remove all infected material from the site. Prune out the smaller branches, sterilizing your pruners after every cut. Sterilize your pruners with rubbing alcohol. It is best to prevent infection by keeping your plant healthy.

Verticillium

This bacterium attacks many trees and shrubs. It resides in the soil and enters the plant through the roots. The disease travels up the plant through the water conducting pathways. As it becomes established in these pathways, water can no longer pass through and the reliant parts of the plant die. Dark brown or purple streaking along the branches will confirm infection. The leaves along the infected branches may become yellow and drop, wilt unexpectedly, or not emerge in spring. Remove all dead wood. If leaves wilt and drop in mid summer, do not remove the suspect branch until the following spring to ensure the branch is dead. Many times a branch will re-leaf and resume healthy growth.

Controls:

There is no chemical control. To avoid infection keep your plants healthy, avoid over watering any plant. If you have lost a plant to verticillium, plant a verticillium resistant plant back in the same area.