Welcome to the “Turf Management Updates” sponsored by the Ministry of Agriculture, Food and Rural Affairs. This message is for the week of Sept. 13 20, 2007.
Weather
We have now had timely rains in most areas of the province and surprisingly the grass has greened up very quickly. What is noticeable, however is that some grass areas have not greened up. This grass, upon close examination has probably suffered some injury from insects feeding on it. The forecast is for some more summer-like weather all week with highs in the mid 20’s but the nights will be cool. These temperatures are favourable for grass growth.
Diseases
There has been a real explosion of dollar spot again this week. I have been expecting to see the first symptoms of Microdochium patch on our research greens, but so far nothing yet. With these cool nights though the disease most definitely will be active and symptoms should be visible soon. With the temperatures and soil moisture being more favourable for turf growth, necrotic ring spot symptoms are lessening. Some areas are still experiencing some rust on Kentucky bluegrass and perennial ryegrass. With the wet weather, there will probably still be some anthracnose basal rot and the perennial problem of take-all patch lingering on golf greens.
Insects
One day last week there were ants swarming every where. I just happened to be out on the research green in the mid-afternoon when this was happening and it was quite exciting. There were so many of them that they were landing on me and getting caught in my hair, etc.. On my walk home, I observed the same thing in the parks and on private lawns. This phenomenon happens this time of year. Over the season some workers develop into winged males and winged females which are the kings and queens of the ant colony. During the late summer these winged ants leave the nest and swarm. Females and males mate and the males die soon after. The mated female (queen) flies to an attractive nesting site, tears off her wings, and encloses herself in a small excavation in the soil, and lays eggs and a new colony is formed.
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.
The adult European crane fly emergence has dropped off significantly in Guelph now. Some of the warmer areas such as Niagara may continue to see heavy adult flights over the next week and then they should taper off. 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.
If you are in the lawn care business and you have lawns with significant damage from hairy chinch bugs or bluegrass billbug, you may be interested to know about some research into endophytic turf grasses. A student of Dr. David Shetlar, Ohio State University named Dr. Doug Richmond performed a set of experiments and found that having 30 to 40% of the stand of lawn grasses containing endophytes is all that is needed to prevent billbugs, chinch bugs and sod webworms from achieving damaging levels. If you are currently overseeding damaged lawns, it might make sense to use endophytic perennial ryegrass.
European chafer grubs are feeding heavily now and growing quickly. Damage will start to show up very quickly now over the next month. Many turf areas have few roots because of all the drought stress and this means that there is quite a potential to see grub damage this fall. For areas that were not treated with Merit, that have significant grub infestation, an application of Sevin T&O will still be effective in controlling grubs. Just be sure to follow the label carefully and water the product in.
Renovation
Our renovation window is quickly coming to a close, so it is important if you have lawns or areas on a golf course to renovate that you get this done very soon. The approach you take for renovations 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. Many non-irrigated areas on golf courses have thinned severely because of traffic on dormant turf. Ensure good seed to soil contact by raking bare areas. On larger properties, golf course fairways and roughs 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.
Weeds
Now that turf and weeds are actively growing you can apply post-emergence broadleaf herbicides. Be sure to be aware of any municipal pesticide by-laws that might restrict or prohibit herbicide use. Also, if you plan to overseed or renovate, it is important that the broadleaf herbicides are applied before overseeding. New seedlings do not tolerate these broadleaf herbicides very well.
Again, thanks for phoning the turf management update for this week. The next report will be recorded on Thurs. Sept. 20, 2007.
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