Fungi often commit their dirty and sometimes fatal deeds in the lawn and garden with the unwitting help of homeowners.
Powdery mildew -- When it comes to prevalence, powdery mildew is No. 1. It occurs on several ornamentals, including crape myrtles, dogwoods, euonymus, crabapples, phlox, grapes and roses. Additionally, squash and cucumbers are likely targets for powdery mildew as well, (good thing to watch for in next year's veggie garden). Powdery mildew is considered mostly a cosmetic problem and can be very persistent. Where powdery mildew has occurred, the leaves of the infected plants should be raked up and destroyed in the late fall and winter to minimize the recurrence of the disease next spring. There are fungicide sprays that can be used, but gardeners need to be willing to make frequent, precise applications.
Photinia leaf spot -- This purple-colored spot on red tip Photinia is caused by a fungus. It's so detrimental that Photinia plants are no longer recommended for your landscape plans. Once the Red Tip is infected, the fungus is spread easily by splashing water and by wind. If the infection is severe, plant removal may become necessary. There are chemical controls, but they require frequent spraying over a long period of time. The fungus can also affect Indian Hawthorne, serviceberry, flowering quince, firethorn pyracanthra and mountain ash, but to a lesser extent. The fungus usually kills plants by repeated defoliation.
Branch canker in Leyland Cypress -- Leyland Cypress is a common ornamental tree often grown as a privacy screen or as an accent ornamental in landscape schemes. It's also become increasingly popular as a Christmas tree. The cypress is very susceptible to a fungus that causes the branches to die from the tips inward. The infection occurs randomly on a plant and if left untreated, the tree can die. Drought-stressed trees tend to be more susceptible to the disease and we've certainly experienced our share of drought this summer.
Dollar Spot of lawn grasses -- Dollar Spot is a fungus disease usually seen on Bermuda grass, but also attacks Zoysia and Centipede. This disease can be seen on poorly maintained lawns that have not been irrigated or fertilized properly. In late summer or early fall, homeowners will see small, straw-colored patches 2-3 inches in diameter. They may go unnoticed until you have a lot of them. The disease can be spotted in the morning hours while there is still dew on the grass. You will see the fungus growing on the leaves, because it looks like shiny little spider webs. This information is often very helpful for diagnosis.
Zoysia Patch -- Another fungal pest is Zoysia Patch, or Large Patch Rhizoctonia solani and the fungus is a close relative of one that causes brown patch in Bermuda grass. This fungus can cause large areas of turf to die and is usually visible either in the fall or in the spring. It can come back every year in the same spot and a lot of times it is associated with an overdose of nitrogen fertilizer and poor soil drainage. Excessive thatch buildup can also contribute. This fungus and several related species are responsible for numerous turf grass diseases (including brown patch and yellow patch) that can occur at any time on warm-season grasses, except during very cold winters. The fungus can be controlled by chemical applications and by correcting drainage, fertilization and thatch issues. It is one of the single most predominant diseases of our grasses that we see here in Arkansas, and thousands of samples are sent to the disease lab in Fayetteville every year for diagnosis.
If you would like more information on the fungi and other diseases that can affect our lawns and plants, visit http://www.uada.edu to find publications. Jimmy Driggers may be reached by calling 501-623-9874 or email, at [email protected]
There are several 4-H Clubs for Garland County youths who are 5 to 19 years old. For more information on all the fun 4-H activities that are available, call Carol Ann McAfee at the Extension office, 623-6841, or email her at [email protected]
Master Gardener information
Master Gardener meetings are held on the third Thursday of each month at the Elks Lodge. They're open to the public and guests are welcome. For more information, call the Extension office at 623-6841.
The Arkansas Extension Homemakers Council is the largest volunteer organization in the state. For information on EHC or joining an EHC club, call Alison Crane at 623-6841 or email her at [email protected]