Dial-a-Garden Message
for the Week of Monday, July 27, 2009
Susan Rose, Horticulture Education Specialist
Colorado State University Extension Tri River Area
Thank you for calling Dial-a-Garden. This message was recorded on Tuesday, July 28, 2009.
Turf diseases have begun coming into our offices frequently. Symptoms may include patchy browning of the leaves and sometimes whole areas dying out completely. The most important key to managing turf diseases is irrigation management. If it is possible to do so, avoid watering the lawn between the hours of 6:00 and 10:00, either in the morning or the evening. The diseases that attack our lawns require an extended period when the leaves are wet, so watering on either end of the normal nightly dew period creates the conditions that favor the disease. Please see the article “Watering Turfgrass and Disease Potential: Leaf Wetness” at http://westernslopeturf.org for more information on this important topic.
Either excess water or drought stress can lead to turf diseases. Water deeply but no more frequently than three times each week; in many cases twice is better. This allows the soil to dry out somewhat between waterings, giving the roots a chance to grow deeper and leading to a healthier, more disease-resistant lawn. Mowing on the highest setting also helps reduce stress on the lawn, and watering for just a few minutes during the heat of the day to cool the lawn off is also helpful. There is a good fact sheet on lawn watering at www.ext.colostate.edu/pubs/garden/07199.html and see http://westernslopeturf.org for additional information.
You may bring your turf in for our diagnosticians if you like. There is no charge for this service. Please bring in a chunk of freshly dug sod about four to six inches across, in which there is both some of the bad area and some healthy grass. These areas along the margins of the diseased or dead spots contain the most information. Our diagnosticians meet weekly in each of our offices and will get back to you with recommendations. If you like, you may take the sample back after we’ve looked at it so you can fill the lawn back in; treat it like new sod if you do.
The locust borer, Megacylene robiniae, attacks trees in the genus Robinia which includes the purple robe locust and other black locusts. It does not bother the honey locusts. This insect emerges in late July and August, lays its eggs in cracks and branch attachments, and the larvae burrow in under the bark where they spend the winter. In the spring, they bore into the wood and this is where the real damage occurs. Trees that are weakened by the boring are susceptible to breaking in high winds. Trunks and larger branches can be sprayed now with an insecticide labeled for borers such as permethrin or carbaryl; an alternative is to treat with soil-applied imidacloprid in the spring or fall, but since this insecticide is slower acting you will still need to spray at this time.
The second treatment for peach crown borer should be applied about thirty days after the first one. If you missed the first one, go ahead and treat the lower trunk now, with an insecticide labeled for borers. If your Prunus spp. trees or shrubs begin dropping leaves or wilt suddenly, check around the base of the tree at soil level and look for damage to the bark in this area. You may also find a gummy residue and some fine sawdust-like material. An Extension fact sheet at http://www.ext.colostate.edu/pubs/insect/05566.html discusses treatments for this insect, or give us a call at 244-1836 and we’ll send you a copy.
Give the Master Gardeners a call with your yard and garden problems. Our offices are open Monday through Friday, except for major holidays. We’re open 8:00 to 5:00, though we do occasionally close for lunch; please call ahead if you are planning to visit between noon and 2:00 p.m. In Montrose, we’re at 1001 North 2nd Street in Friendship Hall; the number there is 249-3935. In Delta we are located at 525 Dodge Street, across the street from the courthouse; that number is 874-2195. In Grand Junction, we are located on the Mesa County fairgrounds at 2775 Highway 50, and our number is 244-1836.
Thank you for calling Dial-a-Garden. This message will be updated next week; have a great week!
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