Weather
We have been in a heat wave in Ontario now for well over a week and record low rainfall also in most areas. The bad news is that there is no rain in sight and the heat wave is going to continue through to Sunday July 24th. Night time temperatures will be higher than normal, with Thursday and Friday’s low at 24°C. Home lawn turf, sports fields and other non-irrigated turf areas are going into dormancy in many areas. On golf courses, non-irrigated turf areas are also going into dormancy. On golf courses, this dry period will be a test of your irrigation systems coverage and performance. Irrigated turf is under stress due to the heat. People are under stress because of heat.
There is a lot of disease activity on golf course turf at the moment. There is a lot of dollar spot activity now with tons or aerial mycelium present first thing in the morning. Brown patch is also active at the moment and the brown patch pressure will continue for at least the next week. There will be a risk of Pythium blight developing later this week (Thurs. and Fri.) if the current forecast remains. Pythium blight develops when temperatures range from 30-35°C, during humid or rainy weather. The most favourable conditions are when relative humidity is greater than 90% for at least 14 hours at a minimum temperature of 20°C. The GTI Turf Diagnostics again this week has had lots of samples with no pathogen detected, so the cause is aboitic/stress related. Some roots have summer patch runner hyphae on them, but no full blown symptoms yet. The good thing about it being hot and dry is that you have a chance to minimize disease by having a good control on your irrigation practices. Keeping things on the dry side and syringing to cool off the turf will help minimize disease development. If you get a torrential thundershower however, you could be in trouble.
On home lawn turf, the only disease to speak of is necrotic ring spot. It is evident on lawns that are not dormant yet, but you can even see some symptoms on dormant lawns. This has definitely been a good year for necrotic ring spot with the wet spring and hot, dry summer.
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.
As predicted last week, black turfgrass ataenius damage is very evident at the moment. The damage first appears as drought stress. Turf in these areas will pull up easily because the roots have been pruned. The actual grubs are usually at the edge of the wilted areas where the turf is still healthy looking and there are still roots for the grubs to feed on. In the Guelph area they are in the late second or early third instar. At this point the damage is almost finished and a curative insecticide treatment will help control the grubs but not the damage. It has been perfect conditions for BTA damage. The rainy spring lead to shallow rooted turf. Then the hot and dry conditions put stress on the shallow turf roots. The final straw was the BTA grubs feed on what was left of the turf roots. I have not had any reports yet of second generation annual bluegrass weevil larvae presence or damage from them yet.
On the subject of grubs, European chafer flights have really slowed down now and are almost over in most areas. Japanese beetles have emerged now. The dry conditions at the time of European chafer and Japanese beetle egglaying could have a negative impact on grub egg survival. This would be an excellent scenario because the turf roots are already compromised by the wet spring and the hot, dry conditions now. If the eggs do hatch, it could be a very bad year ahead for grubs, unless some of them die because it is too dry. I will keep you posted as we start to see grubs developing.
There are numerous pecking holes on golf greens at this time of year. Some of them are due to starlings looking for leatherjackets and black cutworms.
This type of dry summer makes it hard to follow hairy chinch bug damage. When lawns are dormant, you don’t see the chinch bug damage developing. We know that they love all of this hot, dry weather and they will continue to feed on dormant turf crowns. The extent of the chinch bug damage is not usually apparent in a year like this until the fall rains come and the dormant turf fails to green up. Dr. Michael Brownbridge and I are going to put in a chinch bug trial this week. We are hopeful that we can find a bio-control product that is efficacious against hairy chinch bugs. Bluegrass billbug will be feeding also now and their damage will not be evident until we get some rain and see what turf is alive and what is dead.
Now is not the time to be trying to control broadleaf weeds, whether you are using a product like Fiesta or a traditional three way mix. Turf is drought stressed and so are the weeds. It even seems too dry for crabgrass. There is lots of it around, but without a lot of rain it appears to be a bit stunted at the moment.
OMAFRA Pub 384 Recommendations for Turfgrass Management Supplement now available on line.
Products registered to control pests on turf in Ontario are listed in OMAFRA Publication 384, Turfgrass Management Recommendations. The 2011 Supplement, which lists pesticide products that have received registration over the last two years, is now available on line.
During this heat wave, refrain from all cultural practices except mowing. Now is not the time to add stress to turf by aerating, verticutting, topdressing, etc. Skip clean up passes and raise the mowing height if possible. The good news is that summer is almost half over and let’s hope that the second half of summer is less stressful on turf and turf managers than the first half.
I appreciate the feedback. You can reach me by phone at (519-824-4120 x 52597) or by email at pamela.charbonneau@ontario.ca.
– See more at: https://lawnsavers.com/turf-hotline-2011/turfgrass-management-agriphone-for-july-19-2011.html#sthash.oGAppgnR.dpuf
