Fungicides help fight off disease, while insecticides (surprise, surprise) battle insects and other small creatures detrimental to the health of the tree. Preventative treatment aims to prevent diseases or parasites from developing in the first place, whereas curative treatment aims to nurse an already-affected tree back to health; although they often make use of the same products.
Synthetic chemical products (pesticides) are being used less and less in the garden
, and instead being replaced with alternatives that are less harmful to the environment
. Note that use of synthetic pesticides may already be restricted or banned in some areas.
There are three main types of products currently being recommended, and totally compatible with the principles of organic agriculture:
- White oils (and vegetable oils)
- Lime-based washes
- Mineral fungicides.
Bathing the trunk in lime milk
Also known as tree limewash
, lime milk
is an entirely natural product that's been in use for years by gardeners
Lime milk rids the trunk of moss, lichen, microscopic fungi, insects and larvae which inhabit the folds of the tree's bark during winter. It often removes the need for additional treatment against creatures like beetles, psyllids, aphids and codling moth larvae and diseases such as blistering, monilinia and scab. Lime milk should be applied in winter, usually on older trees with cracked or blistered bark.
Using a large, flat paintbrush, brush the solution onto the tree trunk and bases of the major limbs. For better coverage, apply a second coat before the first one dries.
Copper and sulphur are two totally natural products that have been used for centuries against fungal diseases. They are most effective if used preventatively or at the earliest signs of disease. Before treating, check that it's not likely to rain in the following 48 hours so as not to negate the effects of the treatment and have to start over.
Bordeaux mixture and other copper salts
Bordeaux mixture is a cornerstone of organic cultivation
. A combination of copper sulphate and lime, it acts most effectively against mildew
but also against scab in stone fruit trees
, monilinia affecting plum, quince and pear trees, blistering in peaches, oidium in apple trees
, etc. Such treatments on fruit trees must be carried out at the right moment: firstly when the leaves fall in autumn, then during the winter, and the third phase right at the start of spring.
Suplhur is the best preventative and curative remedy for oidium
, also used against scab and blight. Apply the suplhur using a crop sprayer
at a rate of 6g per litre of water onto the leaves, before the flowers blossom, in order to prevent germination of spores.
If it ain't broke... Never apply treatments on a tree which doesn't need it, as they won't do any good. Don't treat in icy conditions, and pick a calm, dry day to avoid wasting your product.