Past weather and the forecast for the upcoming week
Well, it was hot and sticky all last week with a brief reprieve after the storms rolled through on Sat. July 24th. The heat built very quickly again on Mon.,Tues. and Wed. of this week. As of today, the cold front has passed through and daytime highs for the next few days will be around 24ºC. The same trend will begin again with the cooler drier weather building to high temperatures and high relative humidity by mid week next week (Aug. 3rd). There is virtually not rain in the forecast for the next 5 days.
The weather has been conducive for some of the hot weather foliar diseases such as Pythium blight and brown patch. We have some active brown patch here at GTI on the pathology green. With the cooler weather now, it is likely that the brown patch symptoms will not persist. I would say that the conditions were perfect for Pythium blight last Fri. night with the high night time temperatures, high relative humidity and thundershowers. I am curious to know if any one out there saw active Pythium blight on Sat. am. It is a bit difficult to know at this point if you should apply a preventative application for Pythium blight. If you haven’t had it yet, the conditions that favour it are almost over for an entire week so you could probably get away without spraying at this point. The samples that have been received by the GTI Turf Diagnostics have had summer patch, take-all patch, brown patch and algae. If you were not on a preventative program for summer patch it is a bit hard to manage curatively.
he hot weather coupled with the thunderstorms is the perfect combination of conditions for summer patch. There has been an incredible amount of damage from this disease this year, more than we have seen since 2005. When the temperatures are as hot as they were last week, stress turf can be pushed over the edge. The best approach when temperatures soar and relative humidity is high is to do less. Skip a day of mowing, don’t topdress, verticut or apply any unnecessary cultural practices, even fertilizing when turf is so stressed, can cause damage. Watch your watering. Overwatering at this time of year can really promote the hot weather diseases. Go with the “less is more” philosophy. We are just about out of the critical period of turf stress, so hang on tight and hopefully by mid-August it will be over.
Insects
Still lots of calls about Japanese beetle adult flights. My guess is that they will be flying for at least 2-3 more weeks. Japanese beetles seem to be on the move and infesting new areas each year. I did get a call from the Port Hope region saying that they are finding them there. Also they are now in Wasaga Beach area. We are even seeing many of them in Guelph. On golf courses, you can still apply a preventative application of one of the preventative products until the end of this week for the control of both European chafer and Japanese beetle.
The second generation of black turfgrass ataenius are showing up on golf courses now as well as the second generation of annual bluegrass weevils. There has been minimal damage reported from both of these insects.
I have had a few more calls from the field about hairy chinch bug damage. With no rain in the forecast and the temperatures ramping up, we are likely to continue to see chinch bug damage. Again, it is pretty frustrating because there really isn’t an efficacious control for chinch bugs at the moment. I would welcome calls and emails updating me on what you are seeing in the field regarding chinch bug damage.
There are still thousands of sod webworm adults flying around. Again, I am not sure if that bodes well for later this summer. Sod webworm damage usually peaks in mid-September. I will keep you posted about the timing of damage as it starts to occur.
Weed control products
Again, last week was not a good week for applying Fiesta. The label says not to apply when daytime temperatures reach 30ºC. We still appear to be getting good results with the two applications of Fiesta. With only one application, there was significant weed re-growth.
One thing that I forgot to mention last week was crabgrass. There has been an explosion of it over the last two to three weeks. Any areas where the turf had thinned from heat stress are now covered in crabgrass because of the tropic like weather that we have been having. At this point, all you can do is make a note of the affected areas and either wait until the first frost and reseed with one of the cool season grass species or apply corn gluten meal next spring.
– See more at: https://lawnsavers.com/turf-hotline-2010/turfgrass-management-agriphone-for-july-29-2010.html#sthash.uJpCD7oU.dpuf
