Weather
The five day forecast has more rain and cool weather, heating up to low 20’s by the end of the week. We are still below seasonal normals for this time of year. Rain is in the forecast for Mon. and Tues. It has been a relatively quiet week where turf is concerned. The cool weather has meant that there has not been a lot of insect or disease development.
Diseases
The cool temperatures will keep the Fusarium patch active, especially over the next few days with rain in the forecast and overnight lows in the low teens. The dollar spot model developed by Dr. Brenda Nailor is predicting that dollar spot will be starting soon. In Guelph, we have not seen dollar spot yet. It may have started in Niagara and further southwest. The GTI Turf Diagnostics has seen some take-all patch and some Pythium root disfunction over the last week. There is information on submitting a sample to the GTI Turf Diagnostics at the link.
Insects
It has been relatively quiet on the insect front over the last week. Black turfgrass ataenius adult flights are over. Annual bluegrass larvae should be starting to be evident in turf. Larval feeding has been going on now for several weeks and we expect so see the typical annual bluegrass weevil damage any day now Damage first appears as small fist sized clumps of yellowing turf on the edges of fairways and on collars. When the turf is examined, it is annual bluegrass that is dying and when you tug on it, it pulls out easily. European chafter grubs are pupating now and June beetle adults are flying.
Leatherjackets are getting close to the end of their feeding cycle. We are still seeing the pecking holes in greens and surrounds made by starling pecking in the greens to feed on the leatherjackets. We have seen some adult cutworms flying around. They will be laying eggs on golf greens at the moment. They lay their eggs on the terminal portion of the grass blade on golf greens. Daily mowing removes the eggs before they can hatch. If you do discard the clippings close to the green, the emerging caterpillars will migrate into the greens. Remember that one of the best ways to avoid cutworm damage is to dispose of grass clippings away from the greens so that the cutworm larvae cannot migrate back to the greens.
The turfgrass ant will be active for the rest of the season now. They do not eat the turf but feed on other insects present in the turf and soil beneath the turf. The reason that they are a problem is that they form sandy mounds in golf course greens, tees and fairways. These mounds can suffocate the turf, they increase maintenance costs by dulling mower blades and on greens they can disrupt the playing surface. They tend to be more of a problem on new golf courses that have never been treated with the persistent organochlorine insecticides that were used on older golf courses in the past. They are usually within 1-2 m of the edge of a green. They can be treated with insecticide at any time now.
Weeds
I have had quite a few inquiries about replacement product for three way mix broadleaf herbicides and glyphosate under the new act and regulations. Currently, there is one selective broadleaf active ingredient, Sclerotinia minor. For non-selective weed control there are two actives, acetic acid and fatty acid. Acetic acid can be used as a spot treatment for weeds in lawns. The fatty acid products can only be used to control weeds in patios, sidewalks and driveways. These active ingredients are listed in the searchable pesticide database on the MOE website. There are also non-selective weeding tools that rely on super-heated water or propane flames that can kill weeds that are available from various suppliers. There are also hand-weeding tools available.
Over the last week, crabgrass has germinated in the Guelph area. It is now too late to apply corn gluten meal for pre-emergence crabgrass control. Annual bluegrass seedhead production has peaked and is slowing down now. Remember that once these annual grassy weeds flower there is a lot of tiller death, so there could be some thinning of annual bluegrass in the next few weeks.
Fertilization
It is still a good time for an application of fertilizer. Now that the roots are growing well, it is a good idea to fertilize turf so that you can promote a dense turf stand. Fertilizer is now one of the only tools to in lawns and sports fields to help turf out-compete weeds. – See more at: https://lawnsavers.com/turf-hotline-2009/turfgrass-management-agriphone-for-june-5-2009.html#sthash.M9MYeJ5U.dpuf
