Sports Turf Agronomy Advice - July 2024
Just like that we are already at the halfway point of the year. This year, it feels like the summer solstice was upon us before we’d really had any decent weather at all.
There are two distinctive forms of anthracnose infection during the necrotrophic phase; basal rot and foliar blight. The above shows foliar blight on a Poa annua sward showing the characteristic yellowing of leaves and diagnostic black setae.
When looking back at previous months diaries, it is noticeable how each month seems to be that the weather isn’t as expected for the time of year, rather than the weather being on the turf manager’s side. June has definitely been a better month in terms of weather. Temperatures have been up in the late teens, with a good mix of dry spells and showers. Within that, there have been some hot days of 23°C + but also some cool days of temperatures in the low teens, with an occasional heavy downpour, a real mixed bag this month! Which is a vast difference to last June, where we had a month of drought.
An overview of the average weather figures for June are listed below. It has felt a better month all-round although the GP for June is down to 77.75%, from 82% in May, showing a slight drop off in growth. The heavy showers have kept the rainfall figures up with an average of 75mm for the month. GDD have remained relatively consistent and Base nitrogen requirements have crept up to 4.52 Kg of N, from 3.76Kg in May, showing the requirement of some additional Nitrogen from the plant.
Click here if you want to review weather data in your region for June. To keep up to date with the weather throughout June click here
The forecast prediction for July continues where June ended; temperatures are cool with occasional showers. Temperatures are predicted to warm up to late teens into the middle of the month, but to coincide with this the rainfall prediction is also increasing. It isn’t until the last two weeks of the month where we are predicted a combination of warm and dry weather, which should fall nicely for the summer school holidays and the main period of competitions/seasons starting. Long forecast predictions are just that, and everything can change, but let’s hope they have called it correctly.
Highlighted last month was the necessity to be aware of disease pressure, given the significant stress the plant had been under from the environmental conditions. One of those diseases was Anthracnose, a disease which is significantly stress related, low fertility, compaction, moisture etc… Many areas of the U.K will have experienced high temperatures over a 5-day period in June from around the 23rd up to the 27th.
Temperatures reached 24°C + in most areas, with some even recording above 30°C. Warm, humid weather and increased light intensity are the primary environmental factors controlling the development of conidia of Anthracnose (Colletotrichum cereale) with laboratory studies indicating that Colletotrichum cereale produces conidia at temperatures between 24‑32°C, with increased maturity of conidia observed at 28°C compared with lower temperatures. Once conidia have been excreted from the acervuli in a water‑soluble matrix, they can be spread by wind, water or human activity, but need continued leaf surface moisture to establish.
Given this period of weather, it wouldn’t be unreasonable to conclude that conditions will have been conducive for the development of this disease and that practices should be focused on reducing the potential incidence of disease where possible. Anthracnose goes through 3 phases of development: Biotrophic phase, Necrotrophic phase and Reproductive phase. Through the Biotrophic phase, there can be no obvious visual symptoms of the disease; when symptoms do present themselves, it is often too late as the damage is already present.
A pro-active preventative approach to anthracnose increases the probability of reducing any outbreaks compared to a reactive, curative approach. There are several ways in which preventative methods can help; little and often applications of nitrogen have been shown to mitigate the development of the disease as well as cultural stress-reducing practices, biostimulant and elicitor product applications, and also fungicidal treatments if needed, although the above measures may be sufficient in some cases when dealing with this disease. More information can be found on this here.
Pests
Acelepryn is available for those looking for Chafer control, and as we approach the end of the month, timing of applications should start to be considered for best results heading into August. There has been a label change on the full approval in comparison to what was permitted under the emergency approval, so ensure you follow the guidance on the label to make certain it can be applied to your turf area. Speak to your BASIS qualified advisor who will be able to talk through the application guidelines to follow. You can also find all the relevant information on the Syngenta website here.
Tom Wood
B.Sc (Hons) | BASIS | FACTs