The past week was very wet and the forecast is for more of the same. The rain is supposed to stop on Fri. July 3rd, but temperatures are going to remain cooler than normal. Soils are saturated and soft. There has been lots of scalping of turf and heavy disease pressure.
There has been a lot of dollar spot pressure over the last couple of weeks and this is likely to continue with the wet, cool conditions in the forecast. The soil conditions at the moment are setting up nicely for summer patch. This disease does well with wet soil conditions and favours poorly drained sites. The disease develops during the conditions that we have now. Symptoms develop in hot, rainy weather or when high temperatures follow periods of heavy rainfall. Luckily with the cool weather in the forecast we are not likely to encounter symptoms for some time yet. Another disease that is showing up on golf course turf is anthracnose basal rot. Attempting to keep the crowns dry by topdressing is one cultural practice that can help the turf be less susceptible to this disease. Adequate nitrogen also helps. If you encounter a disease that you can’t diagnose, there is information on submitting a sample to the GTI Turf Diagnostics at the link.
There is now a biofungicide product in the disease control tool kit for golf courses and sod farms for dollar spot, anthracnose and brown patch based on a bacteria (Bacillus subtilis strain QST713). The product is marketed under the trade name Rhapsody. Rhapsody is a preventative biofungicide and applications should begin when conditions are favourable for disease development.
Annual bluegrass weevil damage should be almost finished now. We are still finding some larvae, but mostly we are finding pupae and callow adults (newly hatched adults). Expect black turfgrass ataenius damage to peak in the next week or two. Black turfgrass ataenius damage usually is mistaken for drought symptoms or areas where irrigation is uneven. On closer examination, the turf roots have been pruned.
There is more black cutworm damage to report again this week. Last week was a heavy one for adult European chafer flights. They can be seen flying at dusk, in and around trees. Peak adult flights usually occur around Canada Day. Japanese beetle adult are emerging now. The flowering plants that signal peak egg laying of hairy chinch bug are in flower now. We are probably about 3-4 weeks away from the peak damage period. It is a good idea to make note of areas with heavy European chafer flights. These areas can be monitored in the late summer early fall for the presence of chafer grubs. At that point iflots of grubs are found, they can be treated with insect parasitic nematodes.
Last week I said that we were probably out of the window for broad-leaf weed control with Sclerotinia minor. The weather that is forecast for the next week to 10 days will probably be ideal for Sclerotinia minor so lawn care companies may want to resume treatment with it. There will be an other opportunity to use this product in the late summer/early fall. Another weed problem on turf at the moment is moss on putting greens. The persistent wet conditions will favour moss on any greens that have thinned for any reason. Another related problem that we are seeing on greens that are thinning is algae.
At the moment, white clover is flowering in lawns that have not been fertilized regularly for the last few years. With the cosmetic pesticide ban, white clover in lawns is going to become a more familiar site. It isn’t necessarily a bad thing in that it has its own ability to fix nitrogen. – See more at: https://lawnsavers.com/turf-hotline-2009/turfgrass-management-agriphone-for-july-1-2009.html#sthash.KNpY1vmw.dpuf
