Hot, dry weather - here comes the fungus!

Tuesday, April 5, 2011

Once the dog days of summer come along, so does fungus in lawns.  Most lawn diseases are caused by parasitic forms of plant life called fungi which find turfgrass inviting.  Microscopic spores are spread from place to place by wind, water, animals, mowing or people.  Suitable conditions must exist for fungus to arrive, such as temperature range and moisture level for the development of diseases. 

Lawn grasses are more susceptible to disease due to improper mowing, watering, fertilizing or mechanical (mowing) injury.  For a disease to occur there most be a host plant, the disease, moisture and favorable environmental conditions.  A good food supply, proper temperatures and adequate moisture are important for continued infection.  Without any one of these conditions, a disease will not form.

Proper management of the turfgrass is the best way to avoid fungus.  Lawns which are maintained in a healthy, vigorous growing condition are less susceptible to disease.  The first way to avoid disease is to use quality Jonathan Green grass seed mixtures which utilize the latest genetic improvements for superior performance.  Also, buy a mixture that is best adaptable to the site, whether Jonathan Green Sun & Shade Mixture or Heavy Traffic Mixture.  Buy Jonathan Green Black Beauty Ultra Grass Seed Mixture which has insect and disease resistant grasses for species diversity.  It is best to not seed only one variety but, many varieties and species which will help to reduce your insect and disease risk, similar to buying a well diversified stock portfolio.  Your lawn can only be as good as the seed you sow. 

Follow a balanced fertilizing program and use Jonathan Green Lawn Fungus Control if necessary.  Some fungus will be spurred by applying too much nitrogen and others by too little nitrogen.  Excessive amounts of fertilizer can promote lush leaf tissue that is easily penetrated by many fungi.  Applying proper amounts of nitrogen to deficient turfgrass will stimulate the grass to produce leaves faster than the fungus can blight them. 

Mowing at the proper heights stimulates a healthy growing lawn to resists fungus.  Low cuts or scalping and dull mower blades can create wounds limiting the natural ability of turfgrass to resist infection.  Mow your lawn when the grass is dry, particularly when diseases are present.  Leaving clippings or mulching the grass blades will not contribute to disease development.

Moisture is essential for disease development on turfgrass.  Turfgrasses with wet, succulent tissues are easily penetrated by fungi.  Water logged soils inhibit gas exchange and results in dysfunctional roots.  It is important to manage the amount of water on your lawn from both natural rainfall and additional watering to avoid diseases.  Deep, infrequent watering to avoid drought stress is best.  Drought stressed turf lacks vigor and is prone to disease.  Watering early in the morning to allow leaf blades to dry before nightfall is best.  Selective pruning of trees and shrubs helps sunlight reach the grass areas and increases air circulation.

Excessive thatch favors drought stress, and disease survives in the thatch layer. Regular aerification will reduce thatch and soil compaction and will invigorate the lawn, thus reducing the chance of fungus.  There are times once a fungus has set in that you may choose to apply a fungicide.  Properly identify the fungus and apply Jonathan Green Lawn Fungus Control following all label directions, it controls a large number of fungal diseases.  It will last for 21-30 days before another application may have to be made.  Mushrooms or fairy rings do not have chemical controls available.  Aerify the soil, maintain adequate soil moisture, and apply nitrogen to mask the symptoms of mushrooms.  

Disease damage can resemble insect damage.  Be sure you are treating damaged turf from either fungus or insects before you apply any pesticide.  Mother Nature will keep throwing curve balls at us each year.  Follow these tips above to keep one step ahead of her; you may just end up with the best lawn in town!

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