Milk as a fungicide
I came upon this info on the milk question. It appears to be pretty much the
same as the other posting, but with alittle bit more info about the milk
and frequency of spraying. Note also that it says "fresh milk" and that the
effect was first noted with regard to by products of milk processing.This
may mean that pasteurized milk will not work as well.:
THE DOORSTEP PINT has the makings of an ideal fungicide for protecting
organically grown cucumbers and other vegetables, according to researchers
in Brazil. It attacks a mould known as powdery mildew, which is a major
problem for organic farmers scrambling to meet the growing demand for
The mould, Sphaerotheca fuliginea, appears as a powdery white growth on the
leaves of cucumbers and courgettes (zucchini). It damages the plants by
causing the leaves to shrivel up. At present, only chemical fungicides are
Milk's fungicidal powers were discovered by Wagner Bettiol of the
environmental laboratory of Embrapa, the Brazilian Agricultural Research
Corporation, in Jaguariuna, north of São Paulo. Bettiol, who was looking for
cheap ways to control plant pests, observed that byproducts from
milk-processing factories killed powdery mildew on courgettes. So he decided
to simply spray fresh milk on the plants to see if it had the same effect.
To his surprise, he found that it did. In fact, spraying heavily infected
plants twice a week with a mixture of one part cow's milk to nine parts
water was at least as good at stopping mildew as the chemical fungicides
fenarimol and benomyl, Bettiol discovered.
In many cases, milk was both faster and more effective. After two to three
weeks of spraying with milk, the area of leaves infected was in some cases
only a sixth or less of the area affected on plants treated with chemical
fungicide (Crop Protection, vol 18, p 489). Bettiol says several organic
growers in his region have successfully controlled less severe mildew
infections on courgettes and cucumber by spraying once a week with 5 per
cent milk solutions.
Bettiol is not yet sure why milk works so well, but he speculates that it
helps the plants in two ways. Milk is known to kill some microorganisms. It
also contains potassium phosphate, which boosts the plant's immune system
and so may help it inhibit the mildew's growth.
"If this works, it could be very useful," says Rob Haward of the Soil
Association, which sets standards for organic farming in Britain.
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