Welcome to the “Turf Agriphone” sponsored by the Ministry of Agriculture, Food and Rural Affairs. This message is being recorded for the week of July 29-Aug. 5, 2005.
Weather
Last week the weather has been beautiful in southwestern Ontario. It has been a nice break from humidex readings of 35-40ºC. The temperature is supposed to climb over the Aug. 1 long weekend with Monday’s high in the low 30’s. The night time temperatures are predicted to be cool, around 15ºC. It also looks like we will not have a return of the high humidity that we had over a week ago now. After Monday, we are down again to the mid-twenties for 10 days. At least that is what the current long range forecast is predicting.
Diseases
The threat of Pythium blight is over at the moment. Surprisingly, brown patch symptoms seem to be intensifying even though we have moved on to cooler weather. I think this is because of all the rain and saturated soils. The diseases of the week are the root diseases. All week, samples have been coming in to the Turf Diagnostics run by Erica Gunn and the majority of them have either summer patch or take-all patch. Summer patch has been very severe with the heavy rain associated with thunder storms and the hot weather last week. The added problem now is the sunshine and low humidity are producing very high evapotranspiration rates. The turf with summer patch will die very quickly with this weather because it can’t take up the water that it is giving off. The other problem with annual bluegrass at the moment is that it has lost a lot of roots. The saturated soils are making it difficult for the roots to function. Roots need air to do their job. All of this is spelling disaster for stands of annual bluegrass on golf greens. One practice that could help keep your annual bluegrass alive now is to try to back off on the water to let air get into the roots and syringe the plants in mid-afternoon. This is especially critical on heavier soils.
Dollar spot has come back with a vengeance. It does well with the cooler temperatures and loves the heavy dews that we have had over the last several nights. We are even starting to see some severe symptoms on our stands of Kentucky bluegrass so I would expect that it will be rampant on golf course fairways at the moment. We also had some reports of red thread during the week were we had all the thunderstorms.
Insects
Expect so see Japanese beetle adults for another week or two. Unlike European chafer, the adult Japanese beetles feed on a variety of flowering plants and the adults can be observed in the landscape. Merit is registered for control of Japanese beetle grubs in turf.
Now that most areas have had rain, the turf is coming back out of dormancy. Low and behold, the hairy chinch bug damage is now evident in the areas that aren’t greening up. Don’t be fooled however, not all the damage can be associated with chinch bug. Some of the damage was from the long period without rain.
Another insect problem that surfaced this week is sod webworm damage on golf greens. It is not so much the sod webworms themselves, but the birds pecking them out of the greens. A new biorational insecticide has been registered in the last year for controlling sod webworm called Success which contains the active ingredient spinosad. You may want to consider this for the control of sod webworm. The soap flush technique works well to determine if you have them. Again, it is 4 litres of water and 15 mls of dishwashing liquid. Pour that on 0.1m2 of turf and wait for roughly a minute. If the sod webworms are there, they will wriggle to the surface.
I have had lots of call about turf going dark brown to black after the rain. The turf that was dormant and did sustain damage either from chinch bug or high temperature injury may appear black after it rains. This is normal and not something to get too upset about. It isn’t a disease that has gotten in there and damaged the turf. The turf was already dormant or damaged. Again, depending on the type of damage the turf may recover. If it doesn’t, it will have to be overseeded sometime between mid-August and mid-September.
The second generation of black turfgrass ataenius are flying now. If you haven’t had grub damage from this insect by now, chances are you have escaped unscathed. The second generation of grubs rarely cause damage here in Ontario.
Weeds
Wow, where did all that crabgrass come from. The rain that we had in mid-late July has brought on an absolute explosion of crabgrass. The issue here is that turf had thinned in June and July because of the dry conditions. Add a bit of rain and heat and presto – you get crabgrass. There is still time to treat it with Acclaim Super. Again, the nice thing about this is that it fits nicely with IPM in that you can treat only those areas that have crabgrass.
Cultural Practices
Over the next couple of weeks (roughly after Aug. 15), provided that the temperature stays cool, you can start up again with core aeration, verticutting, topdressing, overseeding, etc.. It is also a good time to fertilize turf to help it recover from the harsh conditions that it had to withstand this summer.
Thanks for phoning the turf agriphone message for this week. The next agriphone message will be recorded on Fri. Aug. 5, 2005.
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