controling mould and mildew

as i've mentioned elsewhere, i am starting a fruit and veg garden in a *very* wet place, after a *very* wet year. i am pretty convinced that mould/mildew/fungi could be one of our biggest problems. i'd love to hear any experience of what works to keep these at bay.

we are doing no-dig, so after planting fruit trees and bushes we have mulched all around them with cardboard, sawdust, manure and rushes from a nearby boggy area. i am trying to have all the mulch apart from the sawdust not touch the stems as when i did let the rushes and paper bunch up around the stems they stayed very wet after rain, whereas the breeze dries them this way.

one of the raspberry canes looks as if it has a light grey coating of mildew-type stuff on it. there are some dead hazel branches around which have coral spot fungus on, which i know can spread to fruit bushes. some of the manure we are putting around the plants is not fully rotted. i believe this is ok for using with no-dig as the worms will sort it out over winter - however am i right in thinking that fresher manure creates more of a fungus-y/mouldy environment for plants? the no-dig beds we have created by mulching with hay and manure have mushrooms growing in them, again i believe this is fine as they are just breaking it down - however it illustrates the fungus-rich situation on this land.

i heard about spraying with horsetail or nettle tea - should i do this on the trees and bushes as a preventative, or wait til i think something is definitely infected? are there any other things i should do?

I Know I'm starting to sound like a broken record, but get some Neem Seed Meal, Crustacean(crab, shrimp, lobster) Shell Meal, Kelp Meal (Seaweed), Diatomaceous Earth(liquid potassium silicate if you need a quicker absorption) and some Mycorrhizal Inoculant.
You will probably have to purchase the NSM; You can find the CSM locally at restaurants, fish markets, and your own kitchen; KM can be Purchased, Seaweed can be foraged at the beach, while fishing, pretty much any lake, pond and stream, Just don't take seaweed from protected areas, it may be illegal; DE can be bought online. The Mycorrhizal Inoculant can be purchased online, and at most nurseries.

Do some research on all of these products, see if their right for you, if not then someone on this forum has a less costly alternative, that's not an opinion IT IS A FACT.
Nettle and horsetail tea are great! Good Fungus generally out grows "bad" Fungus in healthy Environments, Just keep a balanced mix, and continue your Nettle/Horsetail sprays. Consider adding alfalfa teas, worm casting teas, seaweed teas, yarrow teas, comfrey teas, dandelion teas, and compost teas add some yucca/aloe and liquid potassium silicate, surfactant and emulsifier respectively. REMEMBER an ounce of prevention is worth a pound of cure.

ok great thanks for all those ideas, i will start preventative measures! many of the ingredients for the teas you've mentioned grow here so i'll get right on that.

i'll look into the other things. the meals and DE - am i right in thinking they are used to provide surface area for 'good' fungi to grow on?

Your welcome!
The plant meals are Micro Organism Feed, the Kelp is a Re-mineralization tool, the DE is a slow release silica source. Silica assists with all around hardiness, and Liquid potassium silicate is an emulsifier for oily sprays. one of the best brands of liquid silica to get is dyna-gro pro tekt, it has 6% potassium silica, where as some of the other silica products have less than 1%.
Add broken natural charcoal briquettes or pieces of lump charcoal for Microbe habitats, and add some liquid nitrogen to the charcoal so it doesn't lock up any that's already present.
for Remineralization you can also use Azomite, Glacial Rock dust, Greensand, or granite dust.