Plant Sanitation. 



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probable explanation of arsenate of lead having proved less effective than Paris 

 green in some cases, according' to reports of fruit-growers, is that it has been too 

 much diluted. This poison was first recommended for use in spraying in 1892 by Mr. 

 F. C. Moulton, an American chemist. When first tested, such weak solutions as 

 6 oz. to 8 oz. to 100 gallons of water- failed to kill caterpillars quickly, while 1 lb. to 

 U lb. were regarded as satisfactory. No injury to apple foliage occurred in a trial of 

 16 lb. of arsenate of lead to 100 gallons, but 3 lb. would be ample, and as that quan- 

 tity has been used in many trials recently, it may be recommended. To make this 

 quantity, according to the formula given above, 3| lb. of acetate of lead and 1\ lb. of 

 arsenate of soda would be required. 



The difficulty of spraying with lime, sulphur, and soft soap, to prevent birds 

 from devouring the buds of gooseberries, has previously been noticed. This is one 

 of the combinations which do not make suitable spray-liquids, as a flaky soap of lime 

 is formed, while the sulphur also is brought out of such combination with the lime 

 as it had made by being added in thin layers, while successive layers of lime were 

 slaked, or by being boiled with the lime. The same objectionable conditions resulted 

 from the addition of soft soap to calcium sulphide properly prepared by a manufac- 

 turing chemist. Therefore, potassium sulphide and soft soap, which combine well, 

 making an excellent .spraying fluid, with some other preparations, Avere tried last 

 season, unsprayed bushes being left as checks. The experiment proved futile, how- 

 ever, as unsprayed and sprayed bushes alike were untouched by birds in the winter of 

 1904-5, possibly because it was an exceptionally mild one. The lime, sulphur, and soft 

 soap spray appeared to have an invigorating effect upon the bushes, while cleansing 

 their stems and older branches of moss and lichen. This season a new combination 

 has been used on gooseberry bushes, consisting of 60 lb. of lime, 30 lb. of flowers of 

 sulphur, and 12 lb. of caustic soda to 100 gallons of water. It has been tried in two 

 seasons in several orchards of apples, pears, plums, and peaches by the author- 

 ities of the New York Experiment Station to kill scale and to check scab 

 and otherwise to act as a caustic spray when buds are dormant. The 

 sulphur is made into a paste, thinned gradually, poured over the quick- 

 lime, and mixed well with it while the latter is slaking, the caustic soda 

 being added and well stirred in immediately afterwards. This is termed a self -boiling 

 spray, and it makes an excellent mixture which, after being strained through 

 fine brass wire gauze, passes freely through the nozzles of the spraying machine. 

 It adheres well to the bushes. 



In one of the apple orchards in New York State this spray is reported 

 to have damaged seriously the leaf and blossom buds ; but the branches of 

 the trees, it is stated, were "repeatedly drenched" and "much oversprayed," 

 In four other apple orchards no appreciable injury was done to the trees. 

 The spray proved very effective for the destruction of scale, and considerably 

 so in checking scab, while leaf-curl in peaches was almost entirely prevented by 

 it. Why this preparation harmed apple buds, even when excessively sprayed, 

 is unaccountable, unless they were too much advanced, as lime and sulphur 

 appeared to invigorate gooseberry bushes, while the mischief is not attributable 

 to the caustic soda, as it occurred also after spraying with lime and sulphur 

 boiled together, without any soda. But the spraying was done in April, which 

 was probably too late in the season. Coating the buds over thickly with lime 

 and sulphur just before the time of expansion may be easily imagined to be 

 possibly injurious; and it is stated that the buds were "well swollen" when 

 the operation was performed. In the four orchards where no appreciable damage 

 was done the spraying was probably much lighter. In full confidence that this 

 mixture will not harm entirely dormant leaf or blossom buds, it has been used 

 this season on apples as well as gooseberries instead of the usual winter wash 



