applied as
suitable compounds such as the sulphates. Both spray applications and
tree injections have great diagnostic values, because a response to
them, if needed is relatively quick. When trees are deficient their
foliage will show marked improvement from a spray application within a
few days, so that a test can be made on a few trees before an entire
orchard is treated. Trunk injections should of course be made during the
dormant season for results to show the following summer.

5) Nutritional Sprays

Florida and California lead in the application of nutritional sprays on
citrus and other fruit[7]. Vegetables, too, respond remarkably
thereto[8]. I see no reason why nut trees likewise should not benefit
from them, especially when other spray materials are used. Copper
sulphate, zinc sulphate, manganese sulphate, magnesium sulphate, iron
sulphate, cobalt sulphate and borax are all compatible with each other
and with most other spray materials. Combination sprays seem to perform
better, anyway, than single sprays, and the only objection would seem to
be that some element is applied that is not deficient. It can be taken
for granted, however, that nothing is wasted, even though the benefits
may be invisible. Soils benefit in the long run from sprays. One
element, even though not noticeably needed, may make another available
or it may antidote toxicity of some element present to excess. Indirect
results in all likelihood are always obtained.

In Florida, recommendations for spray applications to citrus are made
annually[9]. They can be obtained from the Florida Citrus Commission,
Lakeland, Fla. A typical formulae is as follows:

_
3-5 lbs. zinc sulphate |
3-5 lbs. manganese sulphate | per 100 gallons of water or
2-5 lbs. copper sulphate with | other spray material
equal amounts of lime. _|

1 gallon of lime sulphur or 1-1/2 lbs. of lime is used for every 3 lbs.
of sulphate of manganese or zinc.

Cherries, apples, plums are quite responsive to such applications, and I
have seen the defoliation of prune trees in New York State corrected
with a mixture containing:

_
Manganese 10% | All as metallic, in the form of hydrated oxides,
Copper 10% | and applied at the rate of 4 lbs, for the combination
Zinc 5% | material per 100 gallons.
Boron 1% _| The addition of 2 lbs. lime is optional.