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Wickson, Edward J. (Edward James), 1848-1923

"One Thousand Questions in California Agriculture Answered"



Blister Mite on Walnuts.

I am sending you some walnut leaves with some swellings an them. They
are very plentiful on some trees here. Is the trouble serious and will
it spread?
This is merely Erinose, or Blister Mite, which is a very common trouble
on walnuts, but does not do enough damage to call for methods of
control. These swellings are caused by numerous, very small insects
which live within the blisters on the under side of the leaf amongst a
felt-like, heavy growth which develops there. While this effect is very
common, it produces no appreciable injury and needs no treatment for its
control.

Scale on Apricots.

I would like to know how to check the scale on apricot trees.
The most common scale on apricots, the brown apricot scale, is usually
held in check by the comys fusca, which is as widely distributed as the
scale itself. If it gets beyond the parasite, you should spray in winter
with crude oil emulsion. If some scales are punctured or have a black
spot on top, the comys fusca is busy and you probably will be safe
enough without doing anything.

Fumigating for Black Scale.

I would like to know the best method of eradicating the black scale from
my orange trees, whether by spraying or fumigation?
Spraying has been given up as a suitable method for controlling the
black scale on citrus trees, and the only recognized method of merit
where the scale is bad is by fumigation with hydrocyanic acid gas.


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