Barberry bushes are shrubs commonly found in gardens. They are very hardy plants, according to Nature Hills Nursery, tolerating drought and lack of sunlight well. Though these plants can withstand a lot of environmental factors, there are some diseases that still affect them. If you have barberry bushes in your garden, it's good to recognize the signs of these diseases.
Barberry bushes are susceptible to verticillium wilt, a disease caused by the the fungi Verticillium albo-atrum and Verticillium dahliae. Also known as fusarium wilt, the disease is contracted via the soil and infected debris from other plants. Common symptoms of fusarium wilt include leaf drop, discoloration and branches that die and break off. This disease is usually fatal but the length of time it takes to run its course varies from shrub to shrub. Some will die quickly, while others will linger for a year or two. According to the University of Illinois, there is no cure for verticillium wilt.
Another disease that affects barberry bushes is stem rust, according to the University of Illinois. The most common sign of stem rust, caused by the fungus Puccinia graminis, is red-brown growths on the shrub. These growths can appear anywhere on the plant, but are most commonly seen on or around leaves. These growths will continue to grow until they burst, sending out thousands of fungal spores. According to the University of Illinois, one growth can produce more than 350,000 spores. After the growths burst, they then turn black. This is a very serious disease and some communities even go as far as eradicating barberry bushes to control the fungus from spreading to other plants. Certain fungicides, if used properly, can also help control the disease.
Another disease that affects barberry bushes is leaf spot, according to Clemson University. This disease is also caused by a fungus and manifests as black, purple or brown spots that are ringed with yellow on the leaves. The fungus is spread by other plants, insects or pruning with contaminated equipment. Excessive moisture makes a plant more susceptible to the disease, so when you water your bushes, make sure there is enough sun to dry the leaves properly. The best way to control leaf spot is to cut off and remove the infected leaves. The use of certain fungicides can also help control the condition.