GreenCast UK Tech-Notes

STRI Tech Notes - Issue 14 - Early season cut to pathogen numbers

Syngenta — Mon, 28 Jun 2010 18:17:50 GMT

Reducing pathogen populations in the thatch or rootzone, with targeted turf management practices and early fungicide applications, could slow down the onset of damaging disease outbreaks occurring and, over the course of the season, reduce overall treatments and costs, writes Dr Ruth Mann of STRI.

Turf disease can hit with alarming speed and cause severe damage to pristine playing surfaces - in some cases, overnight. Where have the diseases come from? And how do they come about so quickly?

We tend to think of disease control once weather conditions become conducive to that particular disease. For example, warm, sunny days and cooler nights immediately make me think of Dollar Spot. The moisture from cool evenings with heavy dews, combined with warmer daytime temperatures, is perfect for Sclerotinia homoeocarpa, with Dollar Spot symptoms (below, left) tending to be observed shortly after. Unless controlled they can quickly coalesce into large patches of damaged turf surface (below, right).

Similarly, those mild, wet autumnal mornings, when the soil is still warm and the air cooler, herald the beginning of Fusarium Patch season.

When weather conditions are suitable for disease, outbreaks can sometimes flare up before turf managers have time to take any action, resulting in damage that may take weeks or months to repair. The problem is that the pathogens that cause turf disease may survive in the thatch or rootzone as spores or dormant mycelia, waiting for the right conditions to return. In some cases the pathogen will be growing and proliferating in the turf base or rootzone long before we see the symptoms of the disease on the surface.

Using Integrated Turf Management (ITM) to create an environment at the turf base that is unfavourable to the pathogen will therefore reduce its ability to multiply so rapidly and infect the grass plants when weather conditions become favourable.

This can be done in many ways, such as aeration to encourage beneficial aerobic fungi and bacteria in the rootzone that fill the spaces where pathogens would live. These beneficial organisms will also break down organic matter (which is often also the food source for the pathogen to survive on).

The immediate pH around the grass plant is important too. Keeping the pH slightly acidic not only promotes the growth of the finer grasses, but can also reduce the growth of some pathogens, further reducing the potential for disease outbreaks. This is the reason for recommending acidifying fertilisers such as ammonium sulphate. Both of these cultural practices effectively reduce the amount of pathogen inoculum.

Early fungicide application has also been shown to reduce the inoculum of certain diseases. For example, work by Paul Koch of the University of Wisconsin-Madison demonstrated that using chlorothalonil and/or propiconazole in early spring reduced the inoculum of Sclerotinia homoeocarpa and prolonged the period before Dollar Spot symptoms became unacceptable on golf fairway turf.

Propiconazole, as in Banner Maxx and Instrata, being a systemic fungicide, was more effective than chlorothalonil over the three-month period between application and Dollar Spot severity reaching 10% ground cover. It was concluded that this early season fungicide use could reduce the following season-long fungicide programme by up to two fungicide applications, without reducing turf quality - saving time and money.

Therefore, on courses with continual history of a certain disease, applying an appropriate fungicide early in the season - when we know the pathogen is multiplying, but before we see symptoms - may allow a later start date for a conventional preventative fungicide programme without any loss of turf quality.

Click here for more information on ITM plans for turf quality.

Do ITM plans actually work in optimising fungicide use and delivering consistently better turf quality? Have you had any great successes, or spectacular failures? Help others by passing on your experience on the GreenCast forums. Click here to post a coment.

STRI Tech Notes - Issue 13 - Spring overseeding advice

Mark Sanderson — Wed, 24 Feb 2010 17:30:13 GMT

Spring success for over seeding

Following the protracted cold winter, with snow lying for weeks on end in some areas, many turf grass swards are looking less than impressive. A weak, open sward, with residual disease scars and heavy infestation of moss, is not uncommon at this time of the year, writes leading sports turf agronomist, Dr Ruth Mann, of STRI.

Therefore, it is time think about preparing for spring and renovating the turf to bring it back to tip-top condition. However, the first thing to note is that this process cannot be rushed - it all depends on the weather producing good growing conditions so the turf surface can heal as quickly as possible. Moss should be controlled at the first available opportunity, with the residual dead matter scarified out of the sward.

Over seeding may be necessary to aid recovery of the turf from disease and renovation work. If the soil temperatures have increased to around 8 - 10 ºC consistently, an application of Primo Maxx should be considered to hold back the top growth of the existing sward, allowing the new seedlings a better chance of establishment.

Research at STRI has shown that applying Primo Maxx five days before a June over sowing operation allowed significantly better seedling establishment in a bent/annual meadow-grass sward. Using Primo Maxx may also allow the height of cut to be raised slightly without affecting playing quality, which will also be beneficial to the establishing seedlings.

We typically see greater success from over sowing with fescue grasses in spring, and fescue/bent mixes in late summer/autumn.

Once seedlings can be seen, it is important to apply some fertility to encourage establishment. Seedlings need a balanced fertiliser to allow root and shoot growth. A liquid fertiliser or seaweed product will allow the seedlings to obtain enough nutrition to encourage strong establishment. Following establishment, Primo Maxx applications will encourage further root development and tillering in the new seedlings.

For most sports turf surfaces organic matter also needs to be managed in the spring, which turf managers may be able to integrate with an over sowing programme. For seed to germinate and establish, it needs to be in direct contact with the soil, which can prove difficult through a layer of thatch; removing this organic matter improves the chance of seedling establishment.

Removal of organic matter can be done by hollow coring or deep scarification, for example with the Graden. The surface impact will depend on the tine or blade size, which should be determined by the amount of organic matter that needs to be removed. The depth of hollow coring or deep scarification should be just below the base of the thatch layer. If organic matter removal is not required, solid tines or verticutting could be used to form a seedbed, depending on seed size and required depth.

Following organic matter removal any holes of slits should be filled with dry sand to dilute the organic matter present and encourage an aerobic rootzone, allowing the beneficial microbes to proliferate and naturally break down thatch. The Graden sand injection unit enables this process in one pass. Depending on the level of organic matter present, the removal process may take longer than one year.

Seed should then be applied. It is important to ensure the seed is worked into the surface to achieve soil contact, rather than sitting in the thatch. This can be done by broadcasting the seed and manually brushing or dragmatting to work the seed in. Alternatively a seeder attachment on the Graden can place the seed directly into the lines where organic matter has been removed. Another option would be a drill seeder, such as the Charterhouse vertiseed, to place the seed directly into the soil profile at the predetermined depth.

Whatever over seeding process is used, and providing the weather has obliged, after a few weeks the new seedlings should have established and management can resume as normal, hopefully on a top quality grass surface free from imperfections!

Syngenta Turf Nozzles

Mark Sanderson — Sat, 16 Jan 2010 20:07:02 GMT

As the final point of delivery, the choice of nozzle ultimately dictates spray coverage on the leaf and, most importantly, spray retention on the intended target. Syngenta Turf Nozzles have been specifically designed to improve application techniques in turf and to enhance results that can be achieved with Syngenta Turf products. Syngenta Turf Nozzles simply fit into the existing bayonet housing on virtually all modern turf sprayers.

Click on the image below to find out more:

STRI Tech Notes Issue 12 - Fundamentals of fungicide selection

Mark Sanderson — Thu, 26 Nov 2009 16:38:14 GMT

Understanding how fungicides work is paramount to getting the best value for your money from any application. The different modes of action of fungicides, or the way that they tackle disease within the plant, allow you to decide which product to use depending on the disease activity at the time of application, reports Dr Ruth Mann of STRI.

The action of the fungicide and the disease target is also important in deciding the optimum application technique to deliver the treatment where it is required.

Mode of action

The 'topical' mode of action concerns where on the grass plant the fungicide will remain after application:

CONTACTS, such as chlorothalonil (DACONIL WEATHER STIK) and fludioxonil (in INSTRATA), remain on the outside of the grass plant at the point of application, forming a shield to protect the leaf from pathogen attack. They will also help prevent the spread of disease, by preventing the pathogen moving to unaffected plants.

LOCALISED PENETRANTS, such as iprodione can move slightly from the point of application. For example, they may slightly penetrate into the grass leaf or move a short distance around the leaf surface.

SYSTEMICS, such as azoxystrobin (HERITAGE) and propiconazole (BANNER MAXX) can move from the point of application in the xylem (the part of the grass plant that water moves in). These are termed acropetal penetrants and, once absorbed by the leaf, move up through the plant and are redistributed in the leaf. Fungicides applied on the leaf continue to move over time, protecting new leaf as it grows.

It is worth noting that the reason azoxystrobin is effective against take-all is that it also absorbed by the roots and so can prevent growth of the pathogen where it is found in the plant.

The topical mode of action is important for which product will give you the best control depending on the immediate activity of the pathogen. For example, in a high risk situation, where the disease is present and possibly spreading, a fast acting contact fungicide may be most appropriate to immediately protect surrounding clean leaf.

For this reason an acropetal penetrant is likely to give its best results when applied during high-risk situations, but before the disease is observed and spreading. This gives time for the active to be taken up and redistributed within the leaf for much more effective control - preventing the pathogen from infecting the plants.

Biochemical action

The 'biochemical' mode of action concerns how the fungicide prevents or kills the pathogen:

MULTISITE fungicides, such as chlorothalonil and fludioxynil, affect more than one biochemical process within the pathogen.

SINGLE SITE fungicides, such as propiconazole and azoxystrobin affect one biochemical process within the pathogen.

This is important to understand in designing fungicide programmes to prevent resistance developing - which could result in a reduction in the optimal control provided by the available fungicides.

It is very difficult for the pathogen to overcome two or more biochemical processes at once, and so the risk of resistance developing is low for multisite fungicides. Remember that using products with multiple active ingredients from different chemical families acts in a similar way to using a multisite active ingredient, as the product supplies more than one biochemical mode of action.

However, alternating two different products with the same type of activity will not have the desired effect to fight fungicide resistance. For example, azoxystrobin is a strobilurin from the QoI class of fungicides, as are the actives pyraclostrobin and trifloxystrobin. Since they all affect the same biochemical pathway in fungi - fungal respiration at the Qo site - resistance to one of these actives will confer resistance to them all. Therefore, care must be taken to ensure these active ingredients are used within a planned resistance management programme that alternates products from different chemical groups, to prevent resistance occurring.

Click here to view the STRI table showing the biochemical modes of action of different turf fungicide actives.

Application timing

The third thing you need to consider is application timing.

PREVENTATIVE application is when weather conditions conducive to disease development have occurred and there is a high chance that spores will be active on the leaf, but before the pathogen has actually infected the grass plant. Preventative control stops the pathogen before there is any loss in turf quality. It also minimises the risk of further disease spread.

The challenge is to know when to apply preventatively, without wastefully applying when there was little or no disease risk - which is where the combination of good local knowledge and disease forecasting can prove so effective.

CURATIVE application occurs when the pathogen has germinated or just began to grow into the grass plant. Curative activity ends at the very first sign of disease. It should be remembered that in most cases this is the final timing for optimal control with most available turf fungicides.

Most curative fungicides also have preventative activity, so uninfected leaves treated at the same will also be kept clean.

ERADICANT application occurs when the disease is visible and probably spreading. In many instances this is mistakenly referred to as 'curative', but in effect the damage to turf quality has already been done. Most fungicides have only limited effect in curing disease pathogen at this stage, although they can stop its spread by protecting surrounding clean leaf from new infection. Although the fungicide may adequately control the pathogen, you need soil temperatures high enough to allow recovery from the infection. This is why some Fusarium (microdochium patch) scars remain all winter, even though the disease has been controlled.

Click here to download the comprehensive Syngenta Guide to Turfgrass Disease Management for further details and information.

RESCUE GRASS ID GUIDE

Mark Sanderson — Thu, 20 Aug 2009 20:55:04 GMT

Accurate identification of grass species in your existing sward is essential before the use of RESCUE to determine:

(a) Which grasses will be removed

(b) How much turf cover will be removed

(d) The need for over seeding

The easy to use Syngenta Grass Identification Guide, produced in conjunction with specialists from the Sports Turf Research Institute (STRI), provides a quick and reliable means to accurately assess the main turf grass species. The Syngenta Grass ID Guide is uniquely designed to help identify grass species in closely mown turf. Following a route of characteristic physiological features you will be able to determine the grass species present, and make a visual assessment of the sward composition.

Use the pages below as an online guide to grass identification, or cick on the relevant grass to download a printable pdf of the individual page, including further details.

To download a full colour pdf version of the whole guide (8.3mb), click here

If you would like to receive a weatherproof printed copy of the RESCUE Grass ID Guide please email your details to: Karen.Roberts@syngenta.com

STRI Tech Notes - Issue 11 - Fairy Ring

Mark Sanderson — Fri, 24 Jul 2009 23:00:55 GMT

Tech Notes – Issue 11 - July 2009

Fairy Ring Management and Control

Typical autumnal conditions of warm wet/dry cycles have prevailed for the last couple of weeks, resulting in the flaring up of some spectacular Fairy Rings, reports Dr Ruth Mann of STRI.

Many basidiomycete fungi living in the soil or thatch can give rise to Fairy Rings. Growth may be in distinct rings, or in ribbons and arcs, depending on the ring. Some very strange patterns can be observed!

We place the Fairy Rings (or Faerie Rings) into three categories, depending on the visual symptoms in the grass sward.

Type 1 - Rings appear as dead rings of grass perhaps edged by dark green, stimulated growth.

Type 2 - Rings appear as darker green grass with stimulated growth.

Type 3 - Rings appear to not damage the sward visually, but have fruiting bodies (mushrooms or toadstools) present.

The basidiomycete fungus does not directly affect the grass, but changes the environment that supports the growth of the grass, thereby indirectly affecting its growth.

The fungal mycelium grows through the soil or thatch using organic matter as a food source, and releasing nitrogen and other possible toxic substances as waste products. The nitrogen released can stimulate grass growth and is probably the reason why Fairy Rings are much more pronounced in light soils of under lower fertility programmes.

The mycelium itself and substances released during growth make the rootzone hydrophobic. Water is repelled and the rootzone becomes very difficult to rewet. Therefore, grasses may suffer drought due to the rootzone repelling any available water.

Long-term management includes progressive removal of organic matter as the basidiomycetes use it as a food source. Often, in areas with excessive thatch layers, collapse of the thatch can occur as basidiomycetes feed on the organic matter, breaking it down in isolated areas. Aeration is, therefore, important to reduce thatch and also help to improve water penetration.

A good wetting agent programme is very important in maintaining good water receptivity during the drier months of the year. Some wetting agents indicate Fairy Ring management on the label.

For type 2 Fairy Rings, it may be possible to fertilise or apply iron sulphate to mask the visual symptoms and use top dressing to level off any surface depression. For type 3 rings it is usually sufficient to just remove the mushrooms.

Heritage also has a label recommendation for Fairy Ring management. Research at STRI indicted that applying Heritage with H₂Pro following spiking on two occasions, 4 weeks apart, reduced the visual symptoms of a type 2 Fairy Ring.

A high water rate or watering after application is recommended to ensure the Heritage gets into the area of fungal growth.

New application research by Syngenta indicates high-velocity nozzles may be able to deliver better spray penetration of dense turf and achieve better results for Heritage applications for Fairy Ring and Take All and significantly reduced water volume. This could enable faster application, more effective timing and improved results. Go to the GreenCast Application Zone for more information.

Tech Notes Issue 10 - Pre-Stress Conditioning

Karen — Tue, 02 Jun 2009 20:11:13 GMT

Pre-stress conditioning for turfgrass

Now that the turf growing conditions have improved any problems encountered over the winter months can be fixed, to achieve the nice ‘clean’ disease free surfaces we all love. However, very soon we will be into the summer stress period – that is if we get a summer this year!

Although the last two summers have been cold washouts, the long term forecast for 2009 is for a hot, dry summer (and lets face it, we must be due some nice weather). For turfgrass managers, a good summer brings ups and downs. Good weather will encourage use of the sports facility, bringing in some welcome revenue. However, hot, dry weather will also cause heat and moisture stress to the grass plant.

It is time to start planning for that now. April has already been a dry month and soil moisture content in sand rootzones at STRI dropped to levels where the grass plants began to show symptoms of drought stress.

Basidomycete activity has already been observed on many links golf courses, even though the rootzone directly below was not showing hydrophobicity (Plate 1). It can be very difficult to rewet rootzones once they become hydrophobic and so early preventative use of a wetting agent would help to prevent dry soil conditions developing over the summer (Plate 2).

Plate 1: Basidiomycete activity on links course in April 2009

Plate 2: Dry patch symptoms where dry soil conditions have developed

Attention to fertility levels can also have an effect on drought stress. Ensuring plants have adequate potassium can help them overcome drought stress. The movement of potassium regulates stomatal opening and closing, which in turn regulates transpiration.

Applications of Primo MAXX during the summer inhibit the production of gibberellic acid in the grass plant, which reduces cell elongation. Leaves are therefore smaller, with less leaf area for transpiration, making the plants more water efficient and less susceptible to drought stress.

Also, when gibberellic acid levels are reduced, grass plants naturally increase their level of abscisic acid. This abscisic acid alters the osmotic potential of stomatal guard cells through the movement of potassium, causing them to close thereby reducing transpiration during drought stress.

Sequential Primo MAXX applications, to keep the turf in regulation mode, have been shown to produce an increased level of cytokinin in turfgrass. These cytokinins improve the plant's drought tolerance, helping to produce better quality of turf during summer months. Suppressing vertical leaf growth also encourages plants to increase root growth, making them better able to seek out any available moisture.

Bringing together the effects of wetting agent application to prevent hydrophobic soils, good potassium nutrition and sequential application of Primo MAXX could, therefore, have a major effect on the drought tolerance of the grass plant.

To have the grass plants in a position to be able to best withstand summer drought stress periods, however, a programme needs to be put in place to ensure the plants are protected before the stress period begins. Primo MAXX should be applied during the current period of good growing conditions to start increasing root growth and reduce vertical growth.

It is advisable to make initial applications at half dose rate, especially where annual meadow-grass forms a percentage of the grass sward. Tank mixing with a nitrogenous liquid fertiliser, such as Greenmaster 25.0.0, also benefits the grass plant.

Programmes for using Primo Maxx on various sports surfaces can be found here.

Primo MAXX cuts the time and cost of fairway management

Karen — Tue, 02 Jun 2009 16:40:15 GMT

Find out how Primo MAXX can cut the time and cost of fairway managment. Click here to download the Technical Update.

STRI Tech Notes - Issue 9 - Post winter clean up

Mark Sanderson — Thu, 19 Mar 2009 16:29:57 GMT

It’s been a long, hard winter for turf. Autumn came early in 2008, with summer (if that is what we could call it) disappearing in the first week of September, to be replaced by cooler, wet weather perfectly conducive to Fusarium Patch (Microdochium Patch). Most of us were caught out and hadn’t been prepared for preventative treatments (including us ‘experts’ here at STRI).

Fortunately, in the main October allowed a catch up period when grass was still growing enough to allow recovery and ensure it had fungicide protection for the winter.

The winter started very cold. I even thought we might see the good old days of pests and diseases being adversely affected and soil temperatures dropping below zero. However, it didn’t last. Snow lying, in some cases for weeks at a time allowed pathogens to proliferate under their winter duvets. As a result, we have seen some spectacular snow mould emerge when the snow melted (below).

Many golf green and bowling greens are not looking their best following the surge in disease under the snow. As the temperatures increase, renovation can begin to get the surfaces back to full strength as quickly as possible.

Snow mould on untreated plot following 2 weeks of snow cover. Plots in the background treated with Daconil WeatherStik before the snow show almost complete control.

Where eradicant fungicides - such as Instrata or Daconil Weather Stik - were applied after the snow, scarring is still very much apparent. In some cases, as the mild temperatures are returning the edges of Fusarium Patch/Snow Mould scars are becoming active again (below), leading to potential further outbreaks.

This activity should be monitored to prevent any increase in disease as soil temperatures increase and spring fertilisation begins to help grass growth. If active disease is present the use of lawn sand as the first fertiliser will help to reduce the chance of any outbreak.

If weather conditions become conducive to the disease, a fungicide application may be necessary. Soil temperatures will influence your choice of fungicide, as systemic products need the grass to be actively growing and soil temperatures may fluctuate up and down early in the growing season.

In cool conditions contacts - such as Instrata and Daconil - are the initial options, before switching to systemic fungicides - such as Heritage and Banner MAXX - as grass growth speeds up. Check out Greencast for current and 5 day forecasts of soil temperatures in your area.

Once the soil temperatures are high enough to give consistent growth the full spring renovations can begin to fill the gaps and get back to good, smooth and true sward surfaces. We have already discussed spring renovation in an earlier issue - if you missed it and want to know more click here.

Tech Notes - Issue 8 - Fusarium currative

Richard Farnworth — Thu, 26 Feb 2009 20:59:23 GMT

Eradicant action to stop Microdochium patch spread

Heading into the winter months we are back into full-on Microdochium Patch (Fusarium Patch) weather.

GreenCast has been predicting medium to high disease risk on the STRI site at Bingley since early October. This mild, wet weather has really encouraged major outbreaks of Microdochium Patch.

Added to this, the soil temperatures are currently running at around 5ºC, which means we have little opportunity for grass growth and recovery from any infection that develops.

For those who did not manage to apply preventative fungicide treatments and are now seeing patches develop (above), applying a product with eradicant action will need to be taken to prevent the greens from becoming badly affected.

Daconil Weather Stik is one of the mainstays for winter disease control and has shown good eradicant activity in STRI trials over a number of years. Contact fungicides will also prevent any further spread of the pathogen.

The new fungicide Instrata will also offer an excellent package for curative and eradicant winter disease control. Having the new multi-site active ingredient, fludioxonil, it will also protect against the development of resistance in the pathogen population.

The application of iron sulphate will also help to suppress Microdochium nivale growth, and to disguise any patches that have developed.

Tech Notes Issue 7 - Brown Patch

Richard Farnworth — Thu, 26 Feb 2009 20:59:22 GMT

Thunderstorms trigger Brown Patch infection - June 2008

Rhizoctonia Brown Patch is very common in areas of the USA, Central and Southern European countries, where hot weather conditions are common. More recently outbreaks have been observed in the UK, especially where hot days trigger thunderstorms.

The infective pathogen, Rhizoctonia solani, inhabits the rootzone and, when weather conditions are hot enough for infection, may cause brown patch. Rhizoctonia spp. are also often found as a secondary infection or as a saprophyte following other diseases.

Fungicides should be applied at the very first sign of disease, since as Brown Patch can spread rapidly in conducive conditions. Banner MAXX (propiconazole) and Heritage (azoxystrobin) are both approved for Brown Patch control, along with other diseases occurring at the same time. Trials have shown Daconil Weather Stik (chlorothalonil) is also very effective against Brown Patch.

Rhizoctonia brown patch on close-mown bentgrass showing 'smoke-ring'

On close mown grass species (such as bentgrass) Brown Patch can initially be seen as patches of water soaked grass, which develop to become tan to dark brown. In humid conditions a brown/grey 'smoke ring' may develop around the edge of the patch (above). On grass species that are cut higher (such as tall fescue) a light brown patch forms. Individual leaves may have lesions that are tan in the centre and bordered with a brown edge (below).

Rhizoctonia on tall fescue

Rhizoctonia solani tends to affect grasses that are under stress, which is usually temperature related. The weather conditions most conducive to infection are daytime air temperatures over 20ºC (usually the high 20's), persistent humidity or leaf wetness and excessive fertility.

The formation of dew can encourage R. solani, as it uses the carbohydrates in guttation water as a food source. Dew removal is therefore very important to reduce the potential for the pathogen to grow and spread. The use of wetting agents to manage dew may also be considered.

Encouraging good air movement and early sunlight penetration to the grass surface will also help to reduce the time taken for surface moisture to dry. Thatch should be managed by aeration to prevent moisture retention on soil the surface. Avoid excessive nitrogen fertiliser, as lush grass is more easily infected by R. solani.

Where irrigation is required, apply as close to dawn as possible to prevent the surface remaining wet for longer than necessary. Research has shown brown patch was more severe in plots watered in the evening, compared to those watered in the morning - especially in hot weather.

Tech Notes Issue 5 - Anthracnose

Richard Farnworth — Thu, 26 Feb 2009 20:59:21 GMT

Anthracnose attack as weather warms up- April 2008

Anthracnose basal rot is now widespread on sports turf surfaces (above), reports Ruth Mann of STRI. During the winter months, symptoms are seen as individual annual meadow-grass plants becoming yellow. The youngest leaf may turn brick red in colour and a black rot may be present at the base of the stem (below).

Anthracnose is caused by Colletotrichum cereale, which can cause two types of disease depending on the weather conditions. During warm summer months foliar blight may develop. This is often mistaken for drought stress. Any areas that appear droughted should be checked for the presence of acervuli and the hair-like structures called setae (below). Irrigation at this time can exacerbate damage, as it helps to spread the spores of the disease and make further infection more likely.

Under cool, wet conditions basal rot may develop. It is common for basal rot to develop on areas that were infected with foliar blight during summer months. Basal rot is the most commonly identified form of anthracnose in the UK, due to the striking symptoms.

Anthracnose is most severe on annual meadow-grass, but it has also been noted on bent grass and fescue. High risk situations consist of annual meadow-grass dominant swards, and turf grass under stress. Many types of stress predispose turf to anthracnose such as drought, inadequate nitrogen, insect or nematode feeding and excessively low cutting heights.

Managing turf grass to reduce the ingress of annual meadow-grass will make the sward less susceptible to attack. Therefore, attention to fertilisation and irrigation to promote bent grass and fescue should form part of the long-term control measures.

Daconil Weather Stik (chlorothalonil) and Banner Maxx (propiconazole) will both control anthracnose. They are best applied preventatively as, once an annual meadow-grass plant is infected, it cannot be cured. Once symptoms become apparent, curative control will help to protect neighbouring plants that have not been affected.

Anthracnose is often described as a biological indicator - indicating that the turf is not healthy. Therefore, any stress factors need to be alleviated. Nitrogen fertility is often low in areas affected by anthracnose. An application of nitrogen may reduce the stress and suppress the symptoms.

Drought conditions should be avoided on turf dominant in annual meadow-grass to ensure plants are not stressed. Excessively low cutting heights should also be avoided as this adds to the stress on the grass plants; Primo MAXX programmes may enable turf manager to raise cutting height, without adversely affecting turf density and the playing surface quality.

Technical Notes Issue 6 - Over seeding

Richard Farnworth — Thu, 26 Feb 2009 20:59:20 GMT

Spring renovation for turf - April 2008

It has been a pretty cold start to 2008. At Easter in 2007 we were all in tee-shirts and going to the sea-side. This year, we built a snowman!

This is the time of the year I always think turfgrass looks at its worst. It is starting to try to grow but hasn’t got enough temperature, daylight or food to move strongly yet. It appears sad, yellow and in need of a bit of TLC.

However, the soil temperatures are increasing. In the South of the country, soil temperatures are getting to double figures. Further north, they are a couple of degrees behind but almost there.

Spring renovation and fertilisation is especially important if any disease crept in over the winter months and has left unsightly scars. Lawn sand is a good start to the grass growth season, as the little bit of nitrogen helps to slowly break the winter dormancy, without supplying too much fertility at a time when soil temperatures are still low.

Remember that spring renovation and fertilisation needs the grass to be growing for good results so don’t start too soon as the weather can turn cold again leaving greens struggling to recover from the renovation work. Importantly for turf renovation, GreenCast provides a record of current soil temperatures, and the forecast for the coming five days.

The renovation required then depends on the specific management plan for the greens, but will include some of the following aspects. Once the grass has started to grow well, verticutting can be used to remove old dead grass leaves that accumulate over the winter period.

Over seeding can be carried out using a stitch or dimple seeder. I tend to find that when oversowing in spring, applying fescue seed only works best, as the soil temperatures are not always high enough to give good germination of bentgrass seed (which seems to take better following autumn oversowing).

Where turf is actively growing at the time of over seeding, consider the benefits that can be achieved with Primo MAXX applications before and after seeding. This can help to suppress the existing turf and allow new seedlings to establish. (View the news article Over seeding for success).

Microcoring or hollowcoring and topdressing may be carried out as part of an over seeding programme (especially if disease scars need to be addressed). Spring fertiliser and seed can be applied at the same time, and brushed into the tineholes. This fertiliser will then encourage growth.

A soil test will indicate whether the rootzone requires any potassium and phosphorus. During spring (and especially where new seedlings are growing) both P and K are required for new root growth. Therefore, on a soil based rootzone, using a fertiliser such as 6:5:10 N:P:K at 35 g m^-2 or 14:5:10 at 20 g m^-2 will supply a little phosphorus required for rooting and so will help the new seedlings grow and establish. If soil tests indicate enough P and K available in the rootzone, a fertiliser containing 8:0:0 N:P:K could be used. If you wish to use liquid products, Greenmaster Liquid spring and summer contains 12:4:6 N:P:K and could be applied at 80 L ha^-1.

On sand based rootzones, a slow release fertiliser should be considered and a product like Sierraform GT 16:0:16 N:P:K could be used where no phosphorus is required or 18:6:18 N:P:K where phosphorus is required. However, if the sward density is good, it may be appropriate to wait until soil temperatures are consistently around 10ºC and begin a liquid fertiliser/Primo MAXX programme for the whole season.

Tech Notes Issue 3 - Red Thread

Richard Farnworth — Thu, 26 Feb 2009 20:59:19 GMT

Red thread extends to fertile turf

Volume 1, Issue 3 - August 2007

With the recent warm, wet weather, red thread is now widespread on many grassed areas.

Click here for GreenCast details of red thread

Red thread is most common on low nutrition areas such as golf fairways, lawns and parkland. However, more recently it has been affecting areas normally considered to have sufficient fertility - such as football pitches, golf greens and bowling greens.

Close inspection pf suspected red threat infection will reveal pale pink

to red needle or horn-like outgrowths. Pink flocks of mycelium

(resembling candyfloss) may also be present in conducive conditions.

As red thread is traditionally associated with low fertility situations, the most common recommendation for control is an application of 8.0.0 (N.P.K) fertiliser.

With so much rain through June and July, it is possible that swards are suffering from lower fertility than would be expected, due to previous fertiliser applications quickly being leached through the rootzone. This would be especially true in sand dominated rootzones. The addition of an extra fertiliser application may be sufficient to suppress the attack.

Symptoms of red thread create small, mostly circular, patches of

dead leaves interspersed with live plants.

However, red thread infections have been increasingly occurring in areas considered to have sufficient fertility. It is possible that L. fuciformis is adapting to the surrounding conditions and becoming more aggressive. In this situation, especially if the grass sward is thinning, Daconil Turf should be applied to control the outbreak.

Tech Notes Issue 2 - Take All

Richard Farnworth — Thu, 26 Feb 2009 20:59:18 GMT

Early start for take-all patch symptoms

Due to the warm spring and early summer, take-all patch symptoms were starting to be noted in early June this year, a full month ahead of when we normally see the first symptoms in Yorkshire, for example.

View GreenCast details of take-all patch

Take-all patch is most common on newly established golf greens, especially on sand based rootzones where the pH is more alkaline. This is due to a lack of antagonistic fungi and bacteria in the rootzone. As the profile matures, the dominance of the pathogen that causes take-all patch (Gaeumannomyces graminis) diminishes and a natural equilibrium forms.

The brown rings of take-all patch can seriously affect newly established greens, or turf under soil-induced stress.

However, if the equilibrium is upset, G. graminis can dominate the rootzone again and take-all patch may re-emerge. I have most commonly seen this occur following the application of alkaline materials, such as lime or, in one case, where an irrigation water acidifying unit malfunctioned, resulting in alkaline irrigation water being unwittingly applied.

Fungicide with systemic properties will be required to

get down to the roots and kill the take-all patch pathogen,

reports Dr Ruth Mann.

If take-all patch occurs, changes to some management practices can help to alleviate the problem. Fertilising with ammonium forms of nitrogen, rather than nitrates, can help reduce the severity of attack.

Ensuring the grass plant has sufficient manganese is also important; manganese can be bound up at high pH and unavailable to the plant. Gaeumannomyces graminis also actively oxidises manganese, making it unavailable. Therefore, by supplying more manganese in a form usable by the grass plant, symptoms may not be as severe.

Fungicidal control of take-all patch can be difficult as the active ingredient must be able to get to the roots where the pathogen has colonised. HERITAGE (azoxystrobin) is systemic and can be absorbed by root, stem and leaf material, enabling the active ingredient can get to the pathogen and control take-all patch.

HERITAGE is the only fungicide in the UK that has full label approval for control of take-all patch.

Tech Notes Issue 1 Dollar Spot

Richard Farnworth — Thu, 26 Feb 2009 20:59:16 GMT

GreenCast Tech Notes
Dr Ruth Mann
STRI

Volume 1, Issue 1 - June 2007

Time to think about dollar spot control

Spring arrived early this year, although April showers have been a month late. The temperatures are beginning to rise and it is coming to that time of year when dollar spot symptoms may become apparent.

Click here for GreenCast details of dollar spot

There have already been outbreaks in the South of England, although over the past few years the end May/beginning of June generally seemed to be when most Course Managers began to see the symptoms appear. Proactive management is the key to success for dollar spot control.

"Start control of dollar spotpreventatively, and continue through periods of conducive weather." Ruth Mann

Dollar spot is most common where the fertility is low. Keeping the fertility low is also important to encourage the finer grass species, such as fescue, which can be particularly susceptible to dollar spot. The use of liquid feed can help to reduce the potential dollar spot infection but allow you the control to keep the nitrogen input as low as possible.

Dollar spot typically breaks out in late

May or early June, continuing right

through to autumn

Leaf wetness is particularly important for dollar spot infection. Keeping the turf surface dry will help to reduce the potential for infection. If it is necessary to irrigate, it should be done as close to dawn as possible so that the surface can be switched first thing to remove surface moisture.

Registered GreenCast members click here for the current dollar spot forecast

Low cutting height, compaction and excessive thatch can also encourage dollar spot. Therefore, raising the cutting height during conducive conditions, alleviating compaction and reducing the thatch layer through aeration may all help to reduce the severity of dollar spot.

BANNER MAXX and DACONIL TURF are two of the fungicides active against dollar spot. Control is best started preventatively and continued throughout periods of weather conducive to the disease. The mode of action of active ingredients should be rotated to prevent resistance occurring.

Remain vigilant for periods of dollar spot risk throughout the growing season; if the right weather conditions prevail, an outbreak controlled in June may still return with a vengeance in September!

Tech Notes Issue 4 - Fusarium Patch

Richard Farnworth — Thu, 26 Feb 2009 20:59:15 GMT

GreenCast Tech Notes

Dr Ruth Mann STRI

Volume 1, Issue 4 - October 2007

Timing to Control Fusarium Patch

The temperature has suddenly dropped and autumn has come before summer really got started; Fusarium Patch, or microdochium patch as it is often now known, has very quickly come to the fore in recent weeks.

Mild, wet weather will encourage the spread of current disease and further outbreaks. fusarium patch is usually most severe on golf greens dominant in annual meadow-grass, but it can also attack bent and fescue severely, depending on conditions.

Photo by Bob Johnson

STRI research has shown the high levels of Fusarium control achieved with HERITAGE applications timed according to GreenCast disease forecasts, reports Dr Ruth Mann.

Fusarium patches may develop salmon-pink to orange-brown rings of conidia around the outside, with white, pink or grey mycelia growth in conducive conditions. As patches coalesce significant damage can occur, unless controlled with HERITAGE or BANNER MAXX.

The disease is commonly associated with high fertility situations and lush grass growth. However, judicious use of autumn fertilisers low in nitrogen and high on potassium may help improve the plants natural defences, without encouraging lush, susceptible growth. Iron can also be applied to help harden the plant and reduce the potential for infection.

The timing of fungicides for Fusarium Patch control is crucial. Fungicides which act as acropetal penetrants, such as HERITAGE (azoxystrobin), are much more effective when applied at high disease risk but before the onset of symptoms.

Research at STRI has shown that using GreenCast will help to predict when the forecasted weather is conducive to disease infection and optimise damage limiting preventative application timing. A dedicated indicator green can also help to predict when disease is coming. As soon as spots appear on the indicator green, all other greens should be treated preventatively.

Curative fungicide control should be applied at the very first signs of infection. DACONIL WEATHER STIK (chlorothalonil) is very effective applied curatively. Symptoms should not be allowed to develop into larger patches before treatment, since it is very difficult to obtain recovery from damage during the winter months, when grass growth is slow - even after fusarium pathogen (microdocium nivale) has been controlled with a fungicide.

GreenCast sees the future of disease control

Richard Farnworth — Thu, 26 Feb 2009 20:59:14 GMT

How GreenCast can help you manage turf more proactively - to save time and money .... Read the full article here

Fast moving PROLIANCE QUATTRO for total weed control

Richard Farnworth — Thu, 26 Feb 2009 20:59:11 GMT

Details of how to use the new fast acting, high performance glyphosate from Syngenta. Download the full article here.

Fungicide programmes for proactive disease control

Richard Farnworth — Thu, 26 Feb 2009 20:59:10 GMT

How to select the optimum turf fungicide and use the golden rule for Rotation, Rotation, Rotation... Download the full article here