18(J tJoLKAAj. oi:' iiiii JJepaktmkm oi«' Agkicultuhe.- — Alg., i\)22. 



least seveial days followiiifi- applications, mid jjiactieall^' no rain at 

 all after the first api)lication for codlino- control. Results. Ihere- 

 foie, demonstrate conclusively tliat dustinf>' under South African 

 conditions will not satisfactorily cc^ntrol codlinji-nioth and fusi- 

 cladiuni on peais. The writer attributes this failure to the smooth 

 nature of the leaf surface, and particularly to the surface of the 

 fruit in comparison with that of apples, which often have a hairy or 

 waxy surface, and to the fact that codling- infestation is severe and 

 has three })roods in a season in South Africa. The violent south-east 

 winds whi(di })ievail in the Western Province during- ilie truit season 

 have a tendency to remove the dust fiom both fruit ;ind leaves, even 

 if it is applied in the absence of wind. Mr. Dice>', of ()rchai-d Siding, 

 who is to be commended for his progress in attempting' po\\er dusting- 

 for (V)dling- control, found it to be a failure in both apj)le and pear 

 orchards in 1920. Dusting-, however, will play an imj^ojlajit pari 

 in the future in the control of insect pests. It is now used with g^J'^^al 

 success in the control of tobacco, potato, strawberry, and cotton pests 

 in America, and appears to be successful in the control of scab and 

 codling"-nioth on apples where there is only one or a partial second 

 brood of the insect each season (2). Dusting- of peaches for certain 

 fungous diseases has been found to be as satisfactory as spraying- in 

 the United States (2). The control of (-()dling--]noth in walnuts by 

 dusting- is also receiving- attention in (^ilifornia. It is qtn'te possible 

 that dusting- machinery and materials will be so improved in the 

 near future as to extend this method of control considerably and even 

 <o include the control of sucking- insects. At present, howevei-, its 

 application in South Africa is confined to the control of wattle 

 insects in Natal, where the Chief of the Division of Fintoniologry had 

 cxj)eriments beg-un several yeais ago, and which are still in ])rog-ress. 



AcK^'o^VLEnt.MJ•;Ms. 



The wi-iter acknowledg-es the valuable sug-g-estions given b_\ I he 

 Chief of the Division of Entomology concerning- this work, the hel])- 

 ful co-operation of Mr. Shaw, liorticulturist, in the use of the 

 orchard, and the co-oj)eration of Mi-. Jiaker, botanist, in the determi- 

 nation of fusicladium infestation. Dr. Watson-Smith, of tlie Ca}>c 

 l']x})losivt's AVorks, gave valuable assistance in having- the nnH<'rials 

 especially |)iepared for these experiments. 



Litp:ratuhe Ci ikd. 



(1) Bulletins Xo. •"U-") and No. 8()9, Ag-ricultuial lv\])erinienl 

 Station, Cornell University. "Dusting- as a Substitute foi- Sprax- 

 ing-," by Whetzel and liJodg-ett, in Proceedings of Sixteenth Annual 

 Meeting- of the New York State Fruit Growers' Association, January, 

 1917. " The Present Status of Dusting- Apple Trees," by Leonard, 

 in Quarterly Bulletin No. 3, Maine Department of Agriculture, 1920. 

 Numerous other references. 



(2) "Dusting versus Spraying of Apples," by Quaintance. in. 

 the Jovrnal of Economic EntoiiioJui/i/, Vol. XIV, April, 1921. 



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