Is There a Fungus Among Us?

Brown Patch

Summer has arrived with its excessive heat, limitless sunny days, and absence of rain.  The struggle for the homeowner is deciding what is responsible for the brown sections of the lawn.  Is it the sprinklers that aren't covering well?  Is it the lawn guy’s fault because he just fertilized, broke a sprinkler, or repeatedly cuts the lawn too short?  Did someone in my family toss or leave something on the lawn causing it to turn brown?  Is the neighbor’s dog or cat squatting on the lawn?  Are there lawn bugs?  Is it bad soil?  Aliens landing?  Perhaps even a fungus?

An experienced and knowledgeable professional should be able to identify and eliminate most of the above causal agents by taking soil samples, looking at patterns, asking questions, and getting on their hands and knees to look at the soil, thatch, and leaves.  I maintain that lawn diseases are too often made the scapegoat when really something else is causing the problem.  I can’t tell you how many times we have been told that ”My gardener says that I have a fungus” when they just have dry spots in the lawn.

Make no mistake.  We do experience a good deal of disease activity on tall fescue, bluegrass, and ryegrass lawns in the summer months.  Many of these are soil borne or at least lay dormant in the soils or thatch until the proper conditions arrive.  Symptoms are usually spots or circular rings in the lawn unlike many sprinkler or insect patterns.

Brown Patch is probably the most common lawn disease in our market.  It likes hot sunny areas, ample irrigation, poor air circulation, warm nights, and late evening watering.  You can’t control the weather, but you can manage the amount, frequency, and timing of your irrigation.  Deep, less frequent watering that is done between 3-6 am is best.  The sun can then dry out the lawn and leaf blades by mid morning reducing the period of leaf wetness.  

Southern Blight is another fungus that infects the same cool season grasses during the summer.  It has sclerotia, seed like structures, that hibernate in the soils and thatch until the conditions are favorable for “germinating”.  Typically yellow to brown rings of 1-12 feet in diameter will form. We do not feel the watering schedule has a significant impact on its spread or damage.  A preventive fungicide is the key for this one.

Pythium is a water mold and it loves wet and saturated conditions for its spread and infection of the cool season grasses.  It will appear as spots of greasy matted leaves in lawns generally over watered.  This is the least common of the three and can mostly be managed with proper watering practices and use of a fungicide as needed.

We have found that prevention with fungicides is a terrific option. Some offer up to 30 days of protection in our area.  

For more information on lawns please check out our website at Fresno.WeedManUSA.com or call us at 266-1624.

Mowing 101

There are few things nicer than the smell and sight of a fresh cut, lush, beautiful lawn.  Although mowing is not complicated, there are some best mowing practices.  Proper mowing habits can extend the life and vigor of your lawn for years to come whereas poor mowing habits can take a good lawn and make it a poor lawn faster than you might think.

Mow regularly so that you are removing 1/3 or less of the leaf length in a single mowing.  Weekly mowing is advised and during a spring flush of growth a second could be needed.  If the grass has gotten ahead of you and it is twice or more the normal height it would be best to raise the mowing height and come back a day or two later and lower gradually until you reach the preferred height. Do not allow excess clippings to remain on the lawn. Mowing too much off at once will shock the grass and result in scalping.  Two weeks between mowing is too long for a healthy growing turf.

Mow at the proper height for the grass type.  I would recommend 3 inches for tall fescue, 1-2 inches for common bermuda, and 0.5 to 1.5 inches for hybrid bermuda lawns.  Taller cuts result in deeper roots, cooler soils, less stress, and fewer weeds in most cases.

Replace or sharpen dull mower blades regularly to maintain a clean cut. Dull mower blades result in a raggedy cut.  Aesthetically, the lawn will have a dull look and potentially more susceptible to disease.  
Edging should be vertical not beveled off.  A vertical cut along walks and driveways keeps the mowing height in the ideal range leaving a healthier stand, cooler soil, longer root system and a more competitive situation against invading weeds.  If you like the idea of your lawn slowing shrinking away and weeds coming in then scalping down the edges with a string trimmer may be just what you are looking for.

Mow patterns should be varied regularly.  This will help reduce the rutting and spread out the compaction of repeatedly rolling over the same lines time after time.  It also helps reduce the grain of the lawn as it gets mowed from various directions.

Recycle the clippings by using mulching mowers especially during non-flush periods of growth.  The clippings will add much needed organic matter and nutrients to enrich the soil and feed the beneficial microorganisms in the soil.
Mow at a slow enough speed as to allow a good clean cut.  Mow at full throttle.  Going too fast will result in an incomplete cut and possibly excessive piles of clippings.

Other things include removing obstacles and debris before mowing, ensuring that the wheels are evenly inflated or the wheel height settings are all the same, mowing dry grass is preferred over wet, and always being careful of toes when backing up the mower.

For more information on lawns and lawn problems check out our website at Fresn.WeedManUSA.com or call Weed Man at 266-1624.

It’s a Weed, It’s a Grass, No It’s a Sedge!

I know you have seen them. They hibernate in the winter, but by late April they have started to pop up in your lawn. You mow the lawn and for the most part they have disappeared, but by the next afternoon there they are again sticking up above your lawn. Many call these grass-like weeds nutgrass, but actually they are in the sedge family.

The sedge family will have thicker leaves that come in sets of three with triangular stems which is unlike the grass family that has flat or oval stems. In the Central Valley we are blessed with two main types; yellow and purple nutsedge. The color referenced in the name refers to the color of the flower head with yellow ranging from yellow to light brown and purple having a reddish tinge to it. Hopefully you are mowing weekly or as needed and never see the formation of a seed head.

Yellow Nutsedge

Really, I look at the leaves and the underground nutlets to help me determine which one I am dealing with along with my nose and taste buds. Yellow nutsedge has a more slender and lighter green leaf than purple. It tends to grow taller as well. Underground tubers or nutlets form on the terminal end of the rootlets and are round. They are tasty and edible, too and much better if the dirt is washed off first. Purple nutsedge on the other hand has a denser, shinier, thicker, and more blunt leaf. Its underground tubers are scaly and can form in chains like Christmas lights. The soil around them has a distinct smell and the nutlets are bitter tasting. The nutlets can get much larger than the yellow nutsedge at maturity. 

Purple Nutsedge

The key to control is by managing the development of further nutlets. A healthy nutsedge plant will be collecting the sunshine and nutrients to expand both above ground parts and storage of carbohydrates in the formation of tubers. The goal therefore is to disrupt the happy leaf factory. Years ago, Kern County Farm advisor Harold Kempen showed that regular hand pulling of the plants could reduce populations by 60% in the first year and close to 80% or so by year two. Obviously pulling helps, but that is not very practical. There are several selective herbicides that will “hide” the above ground parts for 4-6 weeks thus slowing down the tuber formation and further expansion. I have not seen any silver bullets that fully eliminate nutsedge populations in 1 or 2 sprays, unfortunately. Persistence is the key to reduction and eventual elimination.

Finally, I would advise not over watering the lawn or flowerbeds as this favors expansion as well. Once established, they will do just fine under normal watering practices. If you would like to know more about nutsedge and proper control measures call Weed Man at 266-1624 or visit us at Fresno.WeedManUSA.com.