Trial plots

It’s been a while since my last post and that’s testament to the lack of spare time I get these days, but I am keen on keeping this line of communication between myself and the membership.

Phoenix members will have noticed my trial plots at the rear of 16th, 17th and 18th. If your wondering why these weaker looking squares with disease patches and a lack of colour are on the greens, then I’m going to tell you, but first a background into the products we use to help with disease in autumn and winter. (Grab a coffee some caffeine may help with this one 🥱)

We are sat on 90-95% Poa Annua grass and this is prone to diseases like anthracnose and fusarium patch. As we move into autumn and winter, fusarium is the biggest threat to our greens and most clubs, including Phoenix, spend a lot of money on keeping the greens as disease free as humanly possible. These products include a balanced nutritional feed for the turf, nutrients that make an environment unfavourable for fungal pathogen development, some bio-stimulants/ plant elicitors, dew preventing products and fungicides. 

Keeping the plant healthy with a balanced nutrition is very important. In summer we think mainly of Nitrogen as the plant needs this for most processes of the plant, but in autumn and winter we start to think of other nutrients. Potassium and iron is proven to strengthen the plant against disease pathogens. Manganese can prevent disease pathogens from asserting damage and helps in creating important enzymes in the plant required for a healthy leaf and root system. Zinc is very important and sometimes overlooked, This micronutrient is important for enzyme activation, it is a DNA and RNA catalyst and is an important nutrient in autumn/winter as it can aid the plant roots in water logged anaerobic soils. Magnesium is used to harden the plant and is used to help the plant utilise iron.

Some nutrients help to make the environment hard for fungal pathogens to develop mainly by PH changing or by adding elements like copper that kill bacteria and fungi. You have to be careful with some products like Cu as they a) may kill your soil biology, or b) kill your turf at excessive dosages 😬. Sulphate of iron (FeSo4) is used to change the PH of the soil making it hard for pathogens to develop and this also strengthens the plants natural hardiness against attack. This again has to be used with caution as clay soils in anaerobic conditions can cause black layer (another blog post for that one!).

Plant elicitors and bio-stimulants are used to either encourage soil biology to develop or elicit a plant response from its own immune system. I’ve been a big advocate of bio-stimulants like compost tea, seaweeds, fulvic acid and humid acids etc etc. These really help in making an environment fit for the natural food web and soil biology to to thrive. The hope is that fungi and bacteria like Trichoderma and bacillus subtilis, can form a symbiosis with the plant and fight off or prevent a disease attack. Plant elicitors like phosphite and salicylic acid will elicit a plant response by stimulating the immune system of the plant in to thinking it’s under attack there for releasing certain chemicals to fight off an attack before it starts (hopefully).

One of the main reasons an attack occurs is leaf moisture. Our main job in autumn and winter is preventing dew formation or removing dew formation as this is required for any fungus to develop, as my check plots showed the weekend after bonfire night with mist/fog and dew formation for 72hrs. It takes 5-6 hours of dew for incubation of fusarium fungus so this length of moisture on the leaf is as bad as it sounds. We cut or roll everyday in the summer months so this isn’t much of a concern, but as the growth slows and we cut less we need to remove the dew manually with a large brush that we carry round or apply products that won’t let the dew settle in the first place. These products either sit in the soil or sit on the leaf, the anionic surfactant that sits in the soil has to be used with caution as its not a good idea to abuse this type of surfactant on clay soils as you don’t want deflocculation (another post maybe). The type of surfactant that sits on the leaf is safer but doesn’t last when the grass grows and your cutting it off the leaf. The former will last longer around 14-21 days and needs to be irrigated into the soil or applied in rain, the latter 7-14 days and rain before it drys on the leaf will render it useless and washed off the leaf where you want it.

Next we have fungicides. Most greenkeepers are aware that these are becoming less effective at doing their job, are one day not going to be available, will ruin your soil biology and the soil food web, and are very expensive. These have different ways of stopping the fungi from developing or advancing and we as greenkeepers have to rotate the chemistry and not apply too many, these Chemicals are not to be abused. They can last between 14 and 40 days depending on conditions and additions of growth retarders. All want to and some are going fungicide free and over time are seeing good results with all the other above tools. This is something we will be doing in the next few years and something everyone will have to do in my opinion as these will one day be removed from the market in a bid to clean our environment.

So on to my control plots. I have three control plots and I’m probably going to have more next year. These basically tell me if my expensive products are working and crucially when is it time to go fungicide free in the future. Plot a) on the 17th receives absolutely no products. So it gets no fungicide, no bio-stimulants/ plant elicitors, no balanced feed and no dew removal products. It is left to its own defences and let’s face it, it doesn’t look pretty

Plot b) on the 16th, receives fungicide only but no balanced feed, no bio-stimulants/plant elicitors and no dew removal products. It’s a doing better than plot a) as you would expect but to say it receives a fungicide it is still getting attacked. This shows that there’s more to fighting this disease than just an expensive fungicide. Years ago when fungicides were good this would have kept them a lot cleaner but today’s fungicides lack efficacy but certainly not price.

Plot c) on the 18th receives no fungicide but receives a balanced nutrition, bio-stimulants/plant elicitors and dew removal products. To date it’s staying as clean as the whole green that receives everything including the expensive fungicide.

To conclude this could be showing me I could do this just as good without the expensive fungicide, but I would like to repeat this next year on a different green with higher disease pressure to make sure before I dive in feet first. Should this be the case then swapping fungicide for fine Bents or Creeping Bents greens seed would be the cheaper option and one that would improve the whole green and every green in the long run at Phoenix 

(Other products are available from other manufacturers)