Welcome to the “Turf Management Updates” sponsored by the Ministry of Agriculture, Food and Rural Affairs. This message is for the week of June 28 – July 5, 2007.
Weather:
Today is a very nice change from earlier this week with a drop in the heat and humidity. The last few days have been very stressful on turf. The heat and humidity brought on a flush of disease activity which should subside now for a little bit with the cooler temperatures and low humidity. As with last week, the rain came as thundershowers and was very spotty. There have been lots and lots of turf problems because of the heat and dry conditions. The current 14 day weather forecast shows much cooler temperatures throughout that period, with highs lower than the seasonal norms and ranging from the low to mid-twenties. There is a chance of rain on Tues. after the long weekend and then a chance of a thundershower later in the week. The best news is that the temperatures are going to be cooler than we had last week.
Dry Conditions:
Just a bit of information about the lack of rain, a lawn requires 2.5 cm a week of water will keep it green and from going dormant and of course we have not had any significant rain for several weeks now. To add to this, many municipalities are starting to impose watering restrictions. There is no real problem in letting turf go dormant. A lawn or turf in general can survive for several weeks without water. It will recover when the rains do finally come. It is just a bit more fragile than a lush green stand of turf. Some general things to keep in mind with drought stressed or dormant turf:
Try to keep traffic off of dormant turf
Don’t fertilize or mow dormant turf
Regularly inspect lawn for turf insects
The hot humid weather last week brought on a plethora of diseases. There was some brown patch and lots of dollar spot with lots of dense white mycelium associated with it on some of the mornings. The cooler temperatures and very low relative humidity will keep these diseases in check for the next week or so. Dr. Katerina Jordan has diagnosed several cases of summer patch this week as well as take-all patch. If you do encounter diseases that you cannot identify, don’t hesitate to send a sample in to the GTI Turf Diagnostics Lab. See the link below for details.
Insects:
Leatherjackets have moved down about 2.5 – 3 cm down into the soil and are no longer feeding. This moisture loving insect probably does this to survive the dry conditions that we have in Ontario during the summer. The damage that results from insect pecking out the leatherjackets from golf course turf will probably continue until the leatherjackets pupate in mid to late August. We have passed the window when insecticide treatment for leatherjacket control is recommended.
European chafer adult flights usually peak about this time. There were heavy flights the evenings when the weather was really hot. The adult flights have tapered off a bit with the cooler weather. We are in the ideal application window for preventative grub controls on turf areas that had grub damage in late fall or earlier this spring. Bird’sfoot trefoil is in full bloom at the moment, so that signals peak egg laying of hairy chinch bugs. Expect to start seeing some hairy chinch bug damage showing up in a couple of weeks.
Our soap flushes on greens have brought up some second generation black turfgrass ataenius adults. This makes sense because there was some larval damage showing up a couple of weeks ago. Generally, it is the first generation of grubs that cause damage and you generally don’t have to worry about the second generation. Our soap flushes also brought up a bunch of different caterpillars at different stages. I haven’t had a change to identify them yet. They are still very small, which means that there is probably going to be some damage associated with them. The damage just looks like very small patches of brown turf that usually appear in a bit of a cluster.
I would say that we should be seeing damage from annual bluegrass weevil now. Just to refresh your memory, damage usually begins as small patches of annual bluegrass turning yellow. The annual bluegrass pulls out easily because the weevils have severed the stems from the roots. Heavy populations can cause a lot of damage very quickly. Chlorpyrifos is the only insecticide registered for use on annual bluegrass weevil on Ontario golf courses.
Weeds:
Crabgrass was loving the hot weather last week and it is growing like a weed. With the onset of the dry weather so early this year it really narrowed the broadleaf herbicide window. At this point, it might be best to wait until the fall to apply it.
Remember when all the Kentucky bluegrass was putting out seedheads, now that that is finished, I noticed that the perennial ryegrass is putting seedheads out at the moment. When these get mowed, they leave some very tough yellow stems behind that are very unsightly and can be mistaken for other problems such as disease, etc..
– See more at: https://lawnsavers.com/turf-hotline-2007/turfgrass-management-agriphone-for-june-29-2007.html#sthash.18LpZqzm.dpuf
