The ordinary hand pump and barrel give satisfactory use when placed on a wagon, unless the trees are very high. But for large orchards, high trees, and where larger tanks and power pumps are used it is desirable to have a special truck for the outfit. The front wheel should be made low so as to turn under the tank to enable the driver to make short turns around the trees. A tower is desirable where high old trees are to be sprayed. This should be substantial but as small as is consistent with the purpose so as not to catch on the limbs and make it difficult to get close up around the trees. The height of the platform must be regulated by the need and by the roughness of the ground. On steep side hills the wagon body on which the tank rests should be underslung.
In order to get as near to the work as possible get a long hose—from twenty to thirty feet according to circumstances. The best quality, three to five ply, is none too good. Hose should be three-eighths to one-half inch in diameter, one inch being too heavy. Extension rods are a practical necessity. They should be ten to twelve feet long and made of bamboo lined with brass, that is, as light as possible. Nozzles are very important in thorough and effective spraying. There is no best nozzle, nor one with which all the work can be done.
Several things should be considered in selecting a nozzle. First of all, it must be of convenient form so as not to catch in trees and so constructed that it will not clog easily. Second, for apple trees it should have good capacity and deliver as spreading a spray as possible. Third, the nature of the spray is very important. Insecticides should usually be applied with force in a comparatively coarse driving spray, but fungicides should be applied in a fine mist or fog so that they will settle on every part of the tree. Therein lies the difficulty of applying insecticides and fungicides together.
Time of Spraying.—Fortunately it is not necessary to make a separate application for each insect and disease, but they may be treated together to some extent. In most cases expediency demands that the arsenicals be used with the fungicides. Many growers are finding the most satisfactory results, however, from applying the arsenical spray separately, just after the blossoms fall, because of the physical impossibility of properly applying the two sprays—the driving and the mist spray—together. For most practical purposes on the general farm, three sprayings are necessary in order to secure clean fruit and four, sometimes five, are often advisable. These may be summarized as follows:
1. With lime-sulphur, winter strength, on the dormant wood in early spring.
2. With lime-sulphur and arsenate of lead just before the blossoms open (may sometimes be omitted).
3. With the same (or Bordeaux for scab) just after the blossoms fall.
4. With the same two or three weeks later.
5. With arsenate of lead eight or nine weeks later (may sometimes be omitted).
(In the south and middle latitudes where bitter rot and apple blotch occur two other sprayings may be necessary.)