Myth or No Myth: Turf Maintenance is Tricky Business?

When was the last time you opened up a magazine specializing in golf course management and there was not at least one article about turf maintenance? The reason is that the subject has so many aspects and variables to maintaining that flawless and pristine look golf courses are famous for that the subject is almost never-ending for course owners and superintendents.


Golf Course Management magazine published an article entitled, “Myth Busters” by David Spak, Ph.D., in their January 2007 issue. The article focuses on several common myths involving fungicides for turf maintenance. The article received quite a positive response from readers. So much so that a year later a similar article, “Myth Busters II” by Don Myers (focusing on herbicides), was published in this month’s issue as a follow-up.

Both articles are useful in relation to basic turf maintenance and both discuss common myths relating to the subject matter.

Think you know everything about fungicides?
Dr. Spak lists and discusses six myths to test your knowledge.

• Myth No. 1: Bermudagrass doesn’t get diseases - In newer bermudagrass, cultivars grown on putting greens, however, diseases are definitely becoming more of an issue, perhaps because methods of identifying pathogens have improved dramatically in recent years. The increase in bermudagrass diseases also could stem from our quest for the perfect golf course. The widespread use of ultradwarf bermudagrasses on putting greens and the intense management of these grasses have made them more like creeping bentgrass in their susceptibility to diseases and requirement for fungicides.

• Myth No. 2: Nitrogen fertilization causes disease - Probably one of the most misunderstood phenomena of managing turfgrass disease is the influence of nitrogen fertility. A long-held belief is that nitrogen fertilization will cause or increase turfgrass disease pressure. Although this may be true of some diseases, disease problems on golf courses often are caused by just the opposite — low nitrogen fertility.

• Myth No. 3: Contact fungicides are necessary for curative disease control - When a disease is active, it resides within the plant. Contact fungicides stay on the outside of the plant, protecting the plant from infection. It is true that most contact fungicides will stop the growth of mycelia and cause their collapse. But a contact fungicide will not stop disease already within infected plants. An effective systemic fungicide is needed to “cure” infected plants. It also will stop the growth of the mycelia on the outside of the plant.

• Myth No. 4: Fairy ring symptoms always include mushrooms and rings - Fairy ring symptoms might be localized dry spots in the shape of a ring or many partial rings. You might see mushrooms alone or green rings by themselves. Other symptoms include wilting in a circular pattern or coalescing rings — sometimes in the shape of a Mickey Mouse head! The reason for these diverse symptoms is that fairy ring fungi do not attack the turf; they inhabit the soil, growing on organic matter.

• Myth No. 5: If I see mycelia, it must be pythium blight - Pythium blight is infamous for its cottony, white mycelia. However, a diagnosis of pythium blight based a single sign may not be accurate. Several other diseases can develop white mycelia under the right conditions - an innocent spider web may be misdiagnosed as pythium blight. Active dollar spot can produce mycelia visible in the early morning hours in the presence of dew. Even brown patch can develop whitish mycelia in the early morning hours. Correct diagnosis of these diseases may only be possible with microscopic identification.

• Myth No. 6: Fungicides kill diseases and sterilize the soil - Pesticides are a group of compounds used to control pests, whether they are insects, weeds or diseases. Fungicides are a specific type of pesticide used to manage plant diseases. The true meaning of the word fungicide is “to kill fungus.” Though the suffix “-cide” refers to killing, the meaning is not completely accurate when it comes to fungicides. Most fungicides currently available for managing turfgrass diseases are actually considered fungistats. The suffix “-stat” means to slow growth or to prevent from growing. Fungicides do not kill fungi outright. This is why fungicides may need to be applied repeatedly when conditions are favorable for disease activity.

Click here for a more complete description of the author’s Mythbusters

Killing weeds can be a tricky business.
That is why Don Myers’s dispells a few “common misconceptions about one of the most important tools in a superintendent’s arsenal.”

• Myth No. 1: All pre-emergent herbicides harm turfgrass roots - Not necessarily. Whether a herbicide harms turfgrass roots depends on how the herbicide affects the biology of the plant and the vigor of the desirable turf. Some pre-emergent herbicides, such as oxadiazon, among others, work by affecting the shoot of emerging weed seedlings. Used before the weeds emerge, oxadiazon will control weeds before they sprout and will not harm turfgrass roots.

• Myth No. 2: You should always use an adjuvant when applying herbicides - Adjuvants are used to wet leaves and facilitate coverage by the herbicide product, allowing better penetration into the leaf cuticle. Because many herbicides already contain an adjuvant, it’s not always necessary to add one.

• Myth No. 3: There is a damaging buildup of herbicides after three or four years of use in turf - Environmentally friendly herbicides break down and do not build up in the soil after they have been applied and have completed their job of controlling weeds. Newly registered herbicides meet rigorous standards to assure that accumulation in the environment will not be a problem.

• Myth No. 4: Environmental factors do not matter in regard to herbicide performance - If post-emergent herbicides are applied to drought-stressed weeds, they may not perform effectively. Or, if a heavy rainfall follows a post-emergent herbicide application, the product may be washed away before it has had an opportunity to control weeds. Conversely, if a pre-emergent herbicide is applied during dry conditions and the applicator does not irrigate to activate the product, the product may not perform effectively. Rainfall or irrigation are generally needed for activation. How fast, how well and whether a herbicide works all depend on environmental conditions.

• Myth No. 5: Non-selective herbicides are toxic to all plants. Selective herbicides are safe on all plants - Nonselective herbicides will control the majority of weeds, but not every weed. They will damage most turf or ornamentals if applied directly. Selective herbicides have a significant degree of safety when applied to particular groups of plants, but they can’t be used on every turf type or ornamental.

• Myth No. 6: Once crabgrass germinates, it is impossible to control - Crabgrass is a difficult weed to control once it has emerged. But some herbicides have effective early post-emergence activity and can be used on small crabgrass seedlings. Other post-emergent herbicides are designed specifically for controlling established crabgrass and are well-tolerated by desirable cool-season turf. Bottom line – You can gain control of ugly crabgrass plants, even after they’ve established a foothold in your turf.

Click here for a more complete description of the author’s Mythbusters