SCIENCE OF FRUIT-SPRAYING 333 



that the grower's suspicions are well grounded, and 

 recommend the immediate cutting out and burning of 

 the affected shoots, and indeed of all the upper part of 

 the bushes attacked, healthy and diseased alike, in order 

 to destroy spores. It does not seem to be enough to 

 remove merely those shoots on an infected bush which 

 are actually attacked, as later on those left are almost 

 certain to become affected. The investigator may, at 

 his discretion, advise spraying the bushes with liver of 

 sulphur (sulphide of potassium), and will probably 

 recommend a strength of I oz. to 2j gallons of water. 



The practice of grease-banding trees in autumn in 

 order to check the ascent of moths is worthy of attention, 

 as it is simple and inexpensive. The moth Cheimatobia 

 brumata, parent of the voracious caterpillar commonly 

 called the winter moth caterpillar, crawls up the stems 

 of the trees in autumn and early winter in order to lay 

 its eggs on the shoots, where they will lie until the tree 

 starts growing in spring. We have already seen that a 

 spring spray containing arsenate of lead poisons these 

 caterpillars when they begin to feed ; but if they can be 

 kept away from the tree altogether it is well. 



With the possible exception of the American Tangle- 

 foot grease, all kinds are injurious to the bark of trees, 

 and must be spread on paper. This must, of course, be 

 grease-proof. The paper should be in strips about 6 

 inches wide, and of a sufficient length to encircle the 

 trunk about 4 feet from the ground. It should be tied 

 top and bottom ; if only one string was employed round 

 the middle the moths might be able to crawl underneath 

 it. In any case this may happen if the bark is so rough 

 that the paper cannot be tied close, and the careful 

 grower will put a 3-inch strip of pug (loam, clay and cow 

 manure in mixture of the consistency of putty) round 



