. Better fruit. Fruit-culture. IQII BETTER FRUIT Page 41 The powdery-mildews of the grape and of the rose also belong to this group. These diseases may be prevented by proper fungicidal treatment, the same as disease of group one, and, in addition, they may also be cured by such treat- ment. The mycelium, being exposed upon the surface of the host, may be reached and killed by proper fungicides. For years paris green was used more extensively than any other poison. It first supplanted London purple, but has, in turn, been supplanted by arsenate of lead and various other compounds of arsenic. P
. Better fruit. Fruit-culture. IQII BETTER FRUIT Page 41 The powdery-mildews of the grape and of the rose also belong to this group. These diseases may be prevented by proper fungicidal treatment, the same as disease of group one, and, in addition, they may also be cured by such treat- ment. The mycelium, being exposed upon the surface of the host, may be reached and killed by proper fungicides. For years paris green was used more extensively than any other poison. It first supplanted London purple, but has, in turn, been supplanted by arsenate of lead and various other compounds of arsenic. Pure, it is among the most reliable of insecticides, but has -the dis- advantage that it is a rather coarse crys- talline substance, which settles rapidly to the bottom of the spray-tank unless the contents are kept thoroughly stirred. For codling moth, bud moth, tent cater- pillars and many other insects of group one it is generally used as a spray in the following proportions: (1) Paris green 1 pound Quick lime 4 to 5 pounds Water 160-200 gallons Slake the lime, stir the poison into a thin paste with a little water, add this to the lime, then strain the mixture through a sieve into a tank containing the required amount of water. If it is desired to spray for both fungi and insects, lime-sulphur No. 25, or bordeaux mixture (15 or 16) may be used in place of the water in the above formula. For peach or other tender foliage 300 gallons of water or bordeaux (17) should be used. It is necessary to keep this mix- ture well stirred while spraying. Arsenate of lead is now the chief poi- son used in spraying for the codling moth, although paris green gives approx- imately as good results, and is preferred by some. Many brands of commercial arsenate of lead are now to be had, and so far as our observations go, niearly all are reasonablj^ pure. The various brands may, however, be arranged into the two definite groups, which may be termed the acid arsenates and the ortho or neu- tral arse
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