Welcome to the “Turf Management Updates” sponsored by the Ministry of Agriculture, Food and Rural Affairs. This message is for the week of Sept. 6 – 13, 2007.
Weather
We have had an absolutely beautiful week weather-wise. The temperatures for today and tomorrow are forecast to be hot and humid and then we are forecast to have some more seasonable weather for the next 12 days with highs around 20°C and lows around 10°C. Unfortunately, there is no real rain in the forecast. This means that a lot of fall activities, like broadleaf weed control, etc. will need to be postponed. There is too much drought stress on turf and weeds for herbicide treatments to be effective, unless you are treating irrigated turf.
Diseases
Dollar spot has been pretty active over the last week and with the change in temperature Microdochium patch will probably start to become active because of the cool nights and the presence of dew. Rust continues to be a problem on Kentucky bluegrass and perennial ryegrass stands. GTI Turf Diagnostics continue to have samples with take-all patch submitted and some anthracnose basal rot. If you have disease problems that you can’t identify, please send a sample into the GTI Turf Diagnostics for an accurate diagnosis.
Insects
There have also been lots of adult sod webworms flying around. The damage from this insect usually becomes evident in mid-late September. I would be on the lookout now for signs of sod webworm damage. This includes wilting turf that can easily be pulled away at the thatch/grass crown interface. There are usually small dark green frass pellets in the thatch where sod webworms have been feeding. The soap flush technique, which uses 4 litres of water and a about 15 mls of dishwashing liquid works really well to monitor lawns for sod webworms. Just pour the soapy solution on roughly 0.1m2 of turf and wait a few minutes until the caterpillars emerge.
This week was another bumper week for emergence of European crane fly adults. Emergence usually takes place early in the morning and the adults like to hang out in shady, moist grassy areas or on the shady sides of buildings. Some reports from the field indicate that there are some new areas with European crane fly infestations such as Ottawa. I have had quite a few calls about the best time to treat for leatherjackets. The main period of damage is during the month of May. If damage is beginning to be noticed in early to mid-May, treat before the damage is extensive. This is consistent with the Sevin T&O label which states to treat the later instars. Based on some of the insecticide trial work that we have done, you can get good results if you treat in the spring. This makes it important to make note of areas with large numbers of adult crane flies and to monitor them next spring to determine if treatment is necessary. For those of you with lawn care operations in the City of Toronto, they have just posted information on infestation thresholds for both sod webworms and leatherjackets.
Renovations
Now is the time to renovate those turf areas that have been damaged by insects or disease. The approach you take for renovation will depend on the extent of the damage. If the damage is minimal (small fist sized dead areas) on a Kentucky bluegrass stand, simply fertilizing the lawn will promote turf recovery. Applying 0.5kg of nitrogen per 100m2 now and the same amount in late fall will do the trick.
On areas that have greater damage and the grass species isn’t predominantly Kentucky bluegrass then overseeding and fertilizing will be necessary. The overseeding window in this part of the province (southwestern Ontario) is mid-August to mid-September. Ensure good seed to soil contact by raking bare areas. On larger properties and sports fields, core aeration will help insure seed to soil contact. Seeding rate for overseeding sports fields with perennial ryegrass should be 4 kg/100m2. It is essential to keep the seedbed moist. This may require watering up to 3 times a day until seeds have germinated and seedlings are well established. After seedlings have been up for a couple of weeks, an application of fertilizer of 0.5 kg of nitrogen per 100m2 will help the seedlings get established.
Again, thanks for phoning the turf management update for this week. The next report will be recorded on Thurs. Sept. 14, 2007.
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