rn California, but the disease has never
been troublesome in other sections of the country, as it cannot develop
in dry or hot weather. It affects the tomato as it does the potato,
forming on the leaves dark, discolored spots, which spread rapidly under
favorable conditions, killing the foliage in a few days. The fruit is
also attacked and becomes covered with the mildew-like spore-bearing
threads of the fungus. Bordeaux mixture properly applied is an efficient
preventive.

=Spraying tomatoes.=--It should be the invariable practice of the tomato
grower to spray with Bordeaux mixture to prevent injury from any of
these leaf-blights. This should be done while the plants are still
healthy, as if put off until the disease appears the battle is half
lost. Make the first application to the young plants in the seed-bed a
few days before transplanting. Spray again within a week after the
plants are set in the field, and repeat at intervals of ten days or two
weeks until the fruit is full grown. Success in spraying depends mainly
on the thoroughness of the work. The aim should be to cover every leaf
with a fine mist. Do not drench the foliage but pass to the next plant
before the drops run together and off the leaf. Use a nozzle that gives
a fine spray and maintain a high pressure at the pump.

_Preparation of Bordeaux mixture._--Formula: Copper sulphate
(bluestone), 5 pounds; lime, 5 pounds; and water, 50 gallons. The copper
sulphate may be either in crystals or pulverized. Dissolve by suspending
the required amount in a coarse sack near the top of the water a few
hours before it will be needed. The lime must be fresh stone lime of
good quality. Slake thoroughly by the addition of small quantities of
water at a time as needed, stirring until all small lumps are slaked.
Strain both the lime milk and the copper sulphate or bluestone solution
through a brass strainer of 18 meshes per inch and dilute each with half
the water before mixing together. Do not use Bordeaux left over from
the previous day. An old mixture or one made from the concentrated
solutions has a poor physical condition. It settles more quickly, tends
to clog the nozzle and does not adhere so well to the foliage. Failure
to use the strainer results in endless trouble in the field from clogged
nozzles.

[Illustration: FIG. 42--PROPER WAY TO MAKE BORDEAUX (From W. G.
Johnson)]

When much spraying is to be done it is more convenient to keep the
bluestone and lim