How to get that pesky fungus out of the lawn

I was wondering if you could tell me how do we get rid of fungus in our grass?

— Linda

The first thing is to make doubly sure that it is a fungal disease troubling your lawn.

Though most of the problems in lawns we’re seeing now are due to fungal infection, there are some other possibilities out there as well.

If you’re not sure, have someone take a look at a sample to verify what’s going on. The sample should be a patch of grass about 12 inches square right from the edge of the brown spot; that is, the sample is about half green and half brown. You need to see the transition from healthy to unhealthy grass to tell what’s going on.

There are three fungal diseases common to western Colorado lawns: Melting Out, Ascochyta Leaf Blight and Dollar Spot.

The truth is that differentiating between them is not that important since their behavior and their control is pretty much the same.

There is a fourth disease called Necrotic Ring Spot that occurs rarely and is a different animal altogether and requires a completely different and much more involved treatment regime.

But back to the first three. It’s important to realize that these three diseases are not aggressive pathogens. They attack lawns or portions of lawns that are weak and under stress for some reason. Because of this, we encourage people to look deeper for the possible source of stress that predisposed the lawn to develop the disease in the first place.

Far and away the most common source of stress is watering issues. Too frequent watering, which encourages a shallow root system that is prone to drought and temperature stresses, is often part of the problem but too little water — not watering often enough or, more commonly, not watering deeply enough — will often trigger disease.

Other possibilities are lack of proper fertilizing, improper mowing, soluble salts in the soil and excessive thatch layers, among others.

The bottom line is to do everything you can to ensure that your lawn is as happy and healthy as you can make it. A lush, vigorous, robust lawn rarely, if ever has problems with these diseases.

Fungicides are an effective tool to help combat these diseases, but without correcting any chronic stresses, the disease will reoccur again and again.

The fungicide I recommend most often is Fertilome Systemic Fungicide. It’s a systemic product that will kill existing fungal infections as well as prevent new ones.

Apply it twice, about 10 days apart. If the disease isn’t generally spread throughout the lawn, just treat the spot(s) along with several feet of good grass around the margin.

We are trying to prepare ground for creating a labyrinth. There is a large anthill in this space and we have not been able to remove the ants successfully. Any suggestions?

— Elizabeth

The best luck I’ve had is to drench the hill thoroughly with a liquid ant killer. The insecticide I like best is called Cyfluthrin.

Cyfluthrin is a synthetic pyrethroid which means it is safe for warm-blooded critters but does a dynamite job on the bugs.

Don’t skimp on the amount you apply. You need it to penetrate down deeply enough to kill the queen and she can be pretty deep down. Apply it slowly so it soaks in and just doesn’t run off all over the place.


Which of the ornamental grasses grows the tallest and the fastest?

— Pat

The biggest ornamental grass we grow here is called Ravenna Grass or Plume Grass. The foliage will grow five to eight feet tall.

It’s a clumping, deciduous grass with robust, dense and upright foliage. It sets silvery gray flattened flower spikes that have purple tones in fall. These flower spikes can reach up to 10–12 feet.

Ravenna is an ideal specimen or accent plant and makes a great screen during the summer. It is drought tolerant and hardy to minus 15 degrees.

Dennis Hill is the nursery manager at Bookcliff Gardens, Send questions to Bookcliff Gardens, 755 26 Road, Grand Junction 81506; or email .(JavaScript must be enabled to view this email address).


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