Weather
That blast of heat that we had on the 5th-8th of August brought on lots turf diseases as well as high temperature stress. After that period, we had a slight cooling, but mainly the night time temperatures were going down, even if the day time temperatures were high. That was followed this week by some very clear, hot, windy days with very low relative humidity and high evapotranspiration rates. Looking ahead, this Saturday is going to be hot and humid again but there is a cool front moving in on Sunday. Temperatures will start ramping up again on Wed. Aug. 24th, but at this point in the season it will be rare to see temperatures above 30°C again. There are isolated thundershowers in the forecast for the weekend and day of steady rain for Mon. Aug. 22nd. The rain will be welcome. There have been thundershowers hitting various areas of the province almost everyday but they are not replenishing the soil moisture in the same way that a day of steady rain would.
There are still lots of disease active at the moment. Dollar spot continues to be active. Brown patch has slowed down and there is no longer a risk of Pythium blight developing. The patch diseases are the big news this week. Summer patch continues to plague golf course turf. The high ET’s earlier this week have sucked the moisture out of the turf and if there are shallow roots or roots with disease, the grass plants just can’t keep up. The result is lots of summer patch symptoms and take-all patch symptoms as well. Accompanying these patch diseases is foliar anthracnose that often is found as a secondary problem on already weakened turf. It isn’t over yet because it will be a few weeks before the soils cool down enough to have some turf root growth beginning again at which point we will hopefully see the end of summer patch symptoms.
The GTI Turf Diagnostics lab is reporting a lot of abiotic problems that are associated with the shallow roots, high temperatures, traffic and the high ET rates. Another non-disease issue is that the thundershowers softened the rootzones and resulted in a lot of scalping injury over the last couple of weeks.
On home lawn turf, necrotic ring spot symptoms can still be seen. These are increasing because of the high ET’s that we are currently experiencing. Rust started at the beginning of August in the Guelph area, but it doesn’t seem to be getting any worse yet.
If you do encounter a turf problem that you can’t identify, you can always send a sample to GTI Turf Diagnostics. Information on this service is available on the GTI web site. You can also email them at diagnostics@guelphturfgrass.ca or telephone at (519) 824-4120 x 58873.
This has been a summer where both diseases and insect have been very active. Japanese beetle adults have just finished feeding. There are now 1st instar European chafer and Japanese beetle grubs feeding. We are coming up to the ideal window to apply nematodes for grub control once temperatures cool off slightly. Make sure that the area to be treated is well watered before the nematodes are applied. Do not store the diluted nematode mixtures for more than 3-4 hours. Apply on an overcast, cool day or apply in the early morning or early evening and water the nematodes in as soon as possible. There is a newly commercialized nematode species that has good host specificity for scarab grubs called Steinernema glaseri that might be worth investigating this season. We will be using it as one of our treatments for this years grub control trials. We are outside of the window where the preventative grub control products will be efficacious.
In our hairy chinch bug trials, we are still seeing a lot of 4th instar chinch bugs and just a few adults. This means that there will still be some more feeding damage as those 4th instars grow to become adults.
On golf course turf over the last week there has been a huge outbreak of black cutworms. This is probably the last generation of this multi-generational insect pest that will pester us this year. We are probably two weeks away from the beginning of European crane fly adult flights so keep and eye out for them.
The drought stress has eased somewhat. We don’t have a ton of information about timing with Fiesta and its efficacy. In our past research trials we applied Fiesta a bit later in the fall when both the turf and the weeds are actively growing. This was the traditional timing for our three way broad leaf herbicides. My thought with Fiesta is that if you can weaken it later in the fall it may go into the winter weakened and may die out in the winter. If you treat too early, there may be more re-growth and hence less control. On the note of broadleaf weeds, this is just a reminder that only products with PCP numbers can legally be used to control weeds. Some companies are marketing iron based fertilizers that are not registered for use as herbicides.
Cultural Practices
As we move to cooler, wetter weather (hopefully) it now is a good time for a shot of fertilizer. It is also a good time for core aeration, topdressing, and to plan any renovations that may be needed after one of the most stressful summers we have had. Hopefully, there will be some lessons learned about just how far you can push annual bluegrass growing in poor growing environments and make some changes that will help support turf growth in the future.
– See more at: https://lawnsavers.com/turf-hotline-2011/turfgrass-management-agriphone-for-august-18-2011.html#sthash.icjFhW5c.dpuf
