How can I take care of the fungal problems in my landscape?

ASK THE HORT AGENT

Question How can I take care of the fungal problems in my landscape?

Answer When fungal problems are mentioned, most folks immediately think about black spot on roses and dead areas in the lawn. These types of fungi cause problems, but can be controlled with proper cultural practices and occasional fungicides. A bigger problem occurring in landscapes is the lack of fungi.

There are thousands of fungi living in any pristine natural environment. Some of the smarter, yet lazier, ones have created a way to coexist with plants as friends not foes. A mutually beneficial relationship between a plant and a fungus is called symbiotic. All types of plants, from trees to grass, utilize fungi as allies. This teamwork is called mycorrhiza.

Certain fungi attach themselves to the roots of a plant. The mycorrhiza then send out its own version of roots called mycelium. These growths serve as extensions of the plant’s root system. They absorb water and nutrients which are transported into the plant. A plant’s water and nutrient intake can be increased from 10 to 1,000 times by utilizing mycorrhiza. In exchange for water and nutrients, the fungus is given glucose from the plant.

Mycorrhizal growths are very similar to the bacterial growths legume plants use. Instead of fungi, legumes (like clover, beans, peas, etc…) use bacteria called rhizobium bacteria. This bacteria attaches to the plant’s roots and forms nodules. These nodules of bacteria enable legume plants to convert nitrogen in the soil from an unusable form to a usable form. Therefore, legume plants need very little fertilizer. These plants are often used as cover crops because of their ability to produce usable nitrogen.

Bad fungi attack leaves and take what they need at a plant’s expense. Good fungi not only help plants grow, they also improve soil structure, help plants resist soil born diseases and buffer plants during stressful seasons. Mycorrhiza even protects plants in heavy metal and contaminated soil situations. Good fungi numbers can be depressed (or nonexistent) in landscapes where there is excessive tilling, bare soil, flooded soil, no topsoil or excessive pesticide usage. To increase of the number of good fungi, reverse these problems. You can also buy mycorrhizal products to inoculate your soil.

For more mycorrhiza info, visit http://www.ctahr.hawaii.edu/oc/freepubs/pdf/pnm14.pdf To learn about another beneficial and underappreciated fungi, visit http://www.ipm.iastate.edu/ipm/hortnews/2006/4-5/fungi.html If you don’t have internet access, call the Extension Office at 893-7530 or email me at gpierce@harnett.org

As a NC Cooperative Extension agent, I am an extension of North Carolina State University. Basically, I’m a “mycorrhiza” agent of NC State University waiting for my share of the glucose to increase.

Gary L. Pierce

Horticulture Extension Agent