Preventing slug damage with foliar feeds of Si

I thought some of you in wetter parts of the world might find this study interesting!

Slugs are a serious pest of cereal crops, and recent emphasis in slug pest management has shifted from solely chemical towards integrated approaches. The objective of the present research was to test if boosted silicon (Si) and calcium (Ca) levels in wheat seedlings can reduce slug grazing. Laboratory experiments were conducted in which wheat seedlings were grown firstly, with soluble Si and Ca (with and without additional mineral N) or secondly, with six levels of soluble Si, and consumption of leave sections by the field slug (Deroceras reticulatum) was measured. Boosted foliar Si concentrations reduced consumption significantly (P < 0.001) compared to an untreated control and Ca treatments in a no-choice setting; a similar trend (P < 0.10), but with a higher variability, was observed in a simultaneous choice setting. It is shown for the first time that increasing the nominal Si concentration of treatment solutions in a geometric series (from 0 to 6 g sodium metasilicate nonahydrate l−1) translated into a logarithmic increase in foliar Si concentrations (from 5.0 to 19.4 g Si kg−1 dry weight). When these leaves were offered simultaneously (choice setting), wheat leaves containing less than 10 g Si kg−1 were consumed preferentially by D. reticulatum (P < 0.001), suggesting that Si concentrations as low as 1 % leaf dry weight may be effective at reducing grazing by slugs. It is concluded that boosting Si levels in cereals has potential as a novel tool in crop protection against pest slugs and snails. Various open research questions to advance this tool are identified.


Silicon reduces slug feeding on wheat seedlings

I discovered this after listening to some of Rudolf Steiners agriculture course and then doing some searches with slugs and slica. So its interesting that Steiners emphasis on Ca and Si rather than NPK could be the answer to my ongoing slug issue. Its also interesting to note that my clay soil is abundant with Ca rich limestone.

I dont have access to the whole study but I would assume soluble Si would be molecules like silica, so in true biodynamic style I will be acquiring some horsetail to try this out.

Henry Jabel, how did you get on? Did you try the horsetail, and we're there any beneficial results?

Short answer is no due to various circumstances. e.g This year we had a very dry start to the year so no slugs! However I have relatively recently starting using potsil which is potassium silicate. I have been using this to treat and prevent powdery mildew and it works wonders for this in rambling roses that have had this issue for years- despite best attempts to mitigate this.

However next year if we have a wet spring I will try to remember to use it on some hostas as they usually end up ravaged by the slimy fellows

Thanks for that tip Henry Jabel.

"Short answer is no due to various circumstances. e.g This year we had a very dry start to the year so no slugs! However I have relatively recently starting using potsil which is potassium silicate. I have been using this to treat and prevent powdery mildew and it works wonders"

I am going to give it a go as I get powdery mildew issues in the squash population, as the summer begins to wind down.
I planted kumara slips today (New Zealand sweet potato). We are having a lovely and slightly wet spring, though the slugs, after a damp winter are behaving like killer monsters from outer space. I don't know if you can get anything like postil in NZ, but will check it out, and also see if
Rudolf Steiner had anything to say about herbal applications for potassium silicate.

All the best as you head into autumn winter.

I am fairly certain I first heard about potassium silicate from Glen Atkinson he is in New Zealand thus I think it will be fairly easy for you to get. Even if you imported the stuff I have (that's made in the U.K) a little goes a long way so it still might be worth getting.

Glen also teaches biodynamics and has expanded upon Steiner's work a lot. So you might want to see what he is up to at https://garudabd.org/ and you can always email him.

Wow! Thank you for the awesome tips and lead Henry Jabel. It is always so exciting when someone is from this tiny neck of the woods.
I am working on a second kumara planting today. Janette