206 Appendix. 



APPLE SCAB AND ITS TREATMENT. 



By I'noF. A. B. Coedley, Entomologist Oregon Agricultural College, C'orvalli;^. 

 Address delivered before the Northwest P"'ruit (Jrowers" Convention, I'ortland. 

 January, 1904. 



I think I should apologize for occupying the attention of this audience by 

 talking upon apple scab, a subject that comes up at every fruit growers' meeting 

 on this Coast, and one with which you are no doubt familiar. However, apple 

 scab, not even excepting the codling moth, is the most serious pest of the apple 

 in Western Oregon and Washington. You will remember that at the last 

 meeting of the Oregon State Horticultural Society held here one year ago, in a 

 very vigorous discussion which took place at that time, the A'alue of the ordinary 

 methods of spraying for this disease was seriously questioned, and you will 

 remember that I was asked to make some tests during the tlien coming season 

 and report the results. Therefore, if any apology for my sub.ieet is due, it is 

 from the State Horticultural Society. 



The work I planned should be considered more as a demonstration exercise 

 than as an experiment, because I tried no new methods. I simpfy wished to 

 test those methods which, in conjunction with other experiment stations, we 

 have been recommending for years past, and to report the results. In justice 

 to those who had charge of the work at the college before myself, as well as 

 to myself, I wish to say that the college orchard has for the past ten or twelve 

 years been sprayed for apple scab, but I believe no detailed records suitable for 

 publication have ever been kept of the results. 



The past season I determine, in carrying out m.v i)laus. to make the test as 

 severe as possible, and therefore selected for the work a block of 40o >s'ewtown 

 Pippin trees growing in an orchard near the college. This particular l)lock of 

 trees was selected, first, because, as most of you know, the Newtown I'ippin is 

 on of the varieties most susceptible to apple scab in the Willamette Valley : 

 second, because the orchard has for years been neglected. It is now twlve years 

 old, has never been thoroughly cultivated, and during tliat time it has been 

 spra.yed but two seasons, during one of wliich it received hut one application. 

 The applications were made with the college spraying outfit, wliich consists of 

 a small hand pump that was donated to the college some eight years ago and 

 is now mounted on a 2.")0-gallon tank. The orchard was sprayed five times 

 during tlie season, with the 4-450 Bordeaux, viz : on April 30th. May 14th to 

 19th, .Tune 1st to 3d, .Tuly 1st to 3d, and August ir)th, the last two sprayings' 

 being made more particularly on account of the codling moth, the poison being 

 applied at that time only. These last two applications no doubt liad but little 

 to do in controlling the scab, only the first three being of any benefit. You 

 will notice that the second application was made May l.jth to 19th, whicli was 

 due to the fact that at that time we were blessed with almost continu(nis 

 showers. Thus the application which should have done more good than any 

 •other was applied under adverse circumstances, being made between showers 

 or even when it was raining. 



In the middle of this block of trees, eleven trees were left unsprayed, aud 

 at picking time four trees were selected, two that had been sprayed and two 

 that had not, which stood near together and were as nearly alike as it was 

 possible to select them. The fruit from each tree was carefidly gathered and 

 tlivided into three grades. The first consisted of fruit entirely free from scab : 

 the second, that wliich was slightly scabby, that is, fruit that had one or two 



