Weather
The extreme heat might be over with record breaking temperatures behind us, but it is going to continue to be hot through July 29th. Thundershowers rolled through some areas over the weekend. Temperatures remained hot and will remain hot with the exception of Tues. July 25th. The thermometer will be below 30°C but the humidex for most of the days this week will be above 30°C. The night time lows are not as high as they were last week. Most un-irrigated turf is going into dormancy, with the exception of some shady areas. The thundershowers that fell on the weekend were spotty. If enough rain fell, the turf will bounce back, unless we have another 2-3 weeks without rain.
Dollar spot is steady at the moment. Brown patch is extremely active at the moment and on our non-treated putting greens it is starting to thin the turf in the middle of the patches. Anthracnose foliar blight will also be active on stressed annual bluegrass. The risk of Pythium blight will remain with the thundershowers, high day and night temperatures in the forecast for later this week. 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 most vulnerable areas are those with imperfect drainage. In areas where thundershowers accompany those high temperatures over the weekend, things have set up nicely for summer patch. Expect to see some symptoms developing over the next week. Conditions remain conducive for summer patch at the end of this week, especially in areas that receive thundershowers.
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. I expect to see rust developing soon, but so far I have not see it.
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 is a repeat of last week, but the issue continues to be relevant). 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. In last week’s update I said that I thought the damage was done. New damage occurred all last week as the late second instars continued to feed. There might be one more week of intense damage in most areas because we have not seem any signs of the BTA pupating yet. It has been perfect conditions for BTA damage.
Some reports of the second generation of annual bluegrass weevils are coming in. In a year like this, there may be damage from the second generation.
Japanese beetles continue to feed. This will continue well into August. On golf courses, there is still time to apply a preventative grub control product to control Japanese beetle grubs this fall.
We put out our hairy chinch bug trial last week. There were not as many chinch bugs in the plots as we had hoped, but hopefully we will get some good data. There are lots of chinch bugs out there, but the dry conditions make it difficult to differentiate between chinch bug damage and dormancy. Even if you find chinch bugs, there is not really much you can do to try to control them. We would very much like to find products that are efficacious against hairy chinch bugs.
With the drought stress, dormancy and heat, now is not a good time to try to control weeds. Crabgrass is tillering and putting out seedheads now.
OMAFRA Pub 384 Recommendations for Turfgrass Management Supplement now available on line.
Don’t forget to go online and access the 2011 Pub. 384 Supplement that has the new pesticide registrations for turf for this season.
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.
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-26-2011.html#sthash.8I4cS57h.dpuf
