Weather
Our summer seems to have arrived finally with temperatures actually going above the seasonal norms. There are showers in the forecast today with an expected accumulation of 1-3 mm. That is really not enough to replenish the moisture that we have lost over the past week. Conditions are dry and turf areas that saw no irrigation all summer have been in need of irrigation for a week now. With no rain in the forecast for at least a week, we might see some non-irrigated turf actually go dormant.
Diseases
Dollar spot has slowed down greatly. Disease incidence in general has really slowed down with the exception of rust. All the rain provided good conditions for rust spore germination earlier in the season and now the dry, conditions have slowed the growth of the turf making rust very visible. A shot of nitrogen fertilizer at the moment will help the turf outgrow the rust, provided that there is some moisture available to allow for turf growth.
Insects
There have 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 nematode species Steinernema carpocapse works best to control sod webworm. I am not sure on the exact treatment timing because I have not done any trials with nematodes on sod webworm, but would wait until you see evidence of large numbers of sod webworm before treating. Make sure to follow the label and water before and after treatment.
Over the last two days there has been a real surge of crane fly activity. As I thought, we are a little bit later this year than the past two or three years. I think we are just at the beginning of the adult emergence window. I think we will see large numbers of adult flying over the next week to 10 days. I have done one trial using nematodes in the fall for control of leatherjackets and I did not get good control. I have plans for another trial using nematodes this fall and am targeting the treatments for mid-October.
European chafer grubs are developing quickly now. They are mostly in second instar now and it is advisable to halt all of the nematode treatments should be made.
Weeds
If you have started broadleaf weed control treatments with Sarritor, it is probably a good idea to suspend them until we get some rainy, overcast, cool weather. There is no rush. Providing the weather conditions are suitable, it can be applied into late September to early October and still give good results. Contrary to this spring, Sarritor is in good supply now.
Fertilization and Renovation
If turf hasn’t had an application of fertilizer, now is a good time to apply a balanced fertilizer. This is the first application of the fall fertilizer that is recommended. The second application should go on in late October, beginning of November.
Once this dry period is over, it is the time to renovate those turf areas that have been damaged by insects or disease. Luckily, this season has not been too hard on turf and areas that require renovation should be minimal. 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.
As with Sarritor applications, aeration should probably be suspended until we get some rain and the drought stress has passed. With the cosmetic pesticide ban, we have to be smarter about timing turf seeding to help minimize weed seed germination. If seeding a new turf area now, most of the weeds will be winter annuals that will die out by the beginning of June next year. – See more at: https://lawnsavers.com/turf-hotline-2009/turfgrass-management-agriphone-for-september-10-2009.html#sthash.44Rcg6r1.dpuf
