Notes on Spraying Mixt\ires 



Prof. "W. LocHhead, Macdonald CoUeg'e, St. Anne de Dellevue, Quebec. 



I 



THE value of spraying in orchard 

 practice is seldom questioned now- 

 adays in spite of occasional un- 

 favorable results. It must be acknowl- 

 edged that while we have learned much 

 about the use of insecticides and fungi- 



Spraying in Niagara District 



cides, much remains to be known. The 

 occasional lapses must somehow be 

 examined and explained. Fruit grow- 

 ers sometimes show a little impatience 

 (naturally perhaps) while waiting for 

 accurate information from those whose 

 duties are to secure by careful experi- 

 ments that accurate information. They 

 sometimes take as proven the statements 

 of some "glib" speaker, who, while 

 pretending to be a self-sacrificing hero, 

 is perhaps serving his own ends in ad- 

 vocating some new insect or fungus 

 destroyer. Experiment shows that it 

 is always hazardous to apply on a large 

 scale any remedy which has not been 

 endorsed by the authorities, and its 

 limitations noted. For example, soda 

 Bordeaux, or the "Burgundy mixture," 

 was announced two or three years ago 

 as a better mixture than the JBordeaux 

 mixture. Many fruit growers began 

 using it on a large scale, and they added 

 Paris green. The results were of course 

 disastrous for the reason that the soda 

 unites with the Paris green to form an 

 injurious soluble arsenic compound; 

 on the other hand, the Hme of the Bor- 

 deaux forms a harmless insoluble ar- 

 senic compound. Moreover, recent ex- 

 periments go to show that common 

 Bordeaux gives on the whole better 

 results than soda Bordeaux, and is 

 therefore to be preferred by the fruit 

 grower. 



Again, crude petroleum was heralded 

 as a very efficient destroyer of the San 

 Jose .scale, for good results were ob- 

 tained when applied to apple and pear 

 trees. But it was soon discovered that 

 peach and plum trees were often killed 

 by an application of crude petroleum, 

 and even aonle and pear trees after a 

 few applications showed symptoms of 



injury. Recently also it has been ob- 

 served that strong, healthy shade trees 

 are injured when sprayed too copiously 

 with kerosene emulsion solution. It is 

 now known that kerosene or crude 

 petroleum falling on the ground dur- 

 ing the spraying operations is retained 

 for several years in the soil, gradually 

 finds its way to the tender rootlets, and 

 kills them. It is very probable, there- 

 fore, that the continued applications 

 of crude petroleum year after year to 

 apple and pear trees will result in 

 injury, and orchardists should guard 

 against this by giving up the use of 

 this dangerous substance. 



More information also is given us 

 every year regarding the lime-sulphur 

 mixture. Recent reliable experiments 

 carried out for several years both in 

 the orchard and in the chemical lab- 



oratory tell us that vigorous cooking 

 need not be continued longer than 40 

 minutes to get all the sulphur into the 

 solution; and that the presence of more 

 than five per cent, of magnesia in the 

 lime causes a considerable loss of sul- 

 phur. In view of the fact that much 

 of the lime made in Ontario contains 

 considerable magnesia, more attention 

 should be given to the purchase of 

 good stone hme, free as possible from 

 magnesia. 



Some experiments were also made 

 as to the effect of dipping dormant 

 fruit trees before planting. Apple trees 

 were not injured; but peach trees were 

 frequently injured. These results may 

 have some bearing on the present agita- 

 tion among some nurserymen to have 

 nursery stock dipped instead of fumi- 

 gated. 



TKe Oyster-sKell Scale y\ 



Prof. W. Lochhead, Macdonald College ' 



THE Oyster-shell Scale, often also 

 called the Oyster-shell Bark-louse, 

 is the most abundant and wide- 

 spread insect of the apple orchards of 

 eastern Canada. 

 It is everywhere 

 in evidence, from 

 the far-famed 

 Annapolis Val- 

 ley in Nova Sco- 

 tia to the Great 

 Lakes. Its dim- 

 inutive size and 

 its grey, bark- 

 like color seem 

 to suggest that 

 there is "nothin' 

 a-doin'" where 

 it exists; but 

 there is no enemy 

 of the apple tree 

 more insidious 

 and that re- 

 quires more at- 

 tention than this 

 little oyster- 

 shaped scale. I 

 have seen many 



large apple trees rendered practically 

 worthless and almost lifeless by these 

 insects. Allowed to breed without 

 hindrance for a few years, the scales 

 had practically encrusted the bark of 

 these trees, and had sucked and used 

 the sap that should have contributed 

 to the growth of the new parts, the 

 new wood and the new buds. The 

 trees became "barkbound," and were 

 unable to expand. I saw the same 

 trees a year later, after they had bene 

 scraped and sprayed carefully during the 

 late winter with whale oil soap solution, 



53 



(two pounds to six gallons of hot water). 

 Great rifts had formed in the bark, 

 rendered soft by^the soap solution, and in 

 the rifts new cork was forming. The 



A Wallace Sprayer at Work in Field of Potatoes 



diameter of the stem had increased at 

 least an inch; the oyster shell scales 

 were gone; and the trees were enjoying 

 a vigorous renewal of life. 



Where trees are not suffering to the 

 extent just described, the best treat- 

 ment to get rid of the oyster shell scales 

 is to give two applications of whitewash 

 during the winter. The whitewash 

 is made by slacking about 60 pounds 

 of good fresh lime in 40 gallons of water. 

 Such a wash can be sprayed readily 

 if it is strained before it is poured into 

 the spray pump barrel. The two spray- 



