Page 6 



BETTER FRUIT 



April 



A Spray Program for the Northwest Apple Orchards 



By Leroy Childs, Entomologist and Plant Pathologist, Hood River Experiment Station 



THE accompanying spray calendar 

 is so arranged that it will ade- 

 quately cover the needs of the 

 orchardist in most of the apple growing 

 sections of the Pacific Northwest. It 

 must be understood that this is not a 

 blanket recommendation, for there are 

 indeed but few localities that would 

 demand all of these applications of 

 spray listed in order to effect control of 

 the different apple pests. The orchard- 

 ist must determine, first, the pests that 

 must be controlled in his orchard, and 

 secondly in his procedure, with the as- 

 sistance of his local adviser, determine 

 whether seasonal conditions warrant 

 the alterations of the program. The 

 calendar presented is arranged to meet 

 maximum adversities from the stand- 

 point of weather conditions and pest 

 development, with a result that during 

 many seasons decided alterations may 

 be necessary. In the alteration of these 

 arranged sprays the advice of an expert 

 orchard investigator should be obtained 

 if possible. 



Seasonal development is the most im- 

 portant factor is making the necessary 

 alterations in any spray schedule. 

 Usually a late spring is a decided ad- 

 vantage to the orchardist from the 

 standpoint of the number of sprays that 

 will be necessary during the season. 

 This is especially true in the control of 

 apple scab. In order to completely pro- 

 tect the orchard from the disease it is 

 necessary to keep the foliage protected 

 from the delayed dormant stage (Fig- 

 ure 1) until the spring rains are over. 

 Under the conditions which exist at 

 Hood River rains can be expected until 



about the first of July. Two applica- 

 tions a month are necessary to keep the 

 foliage and developing fruits coated, so 

 that if the delayed dormant stage is 

 reached by April 1, which often hap- 

 pens, it would be necessary to make 

 five application of a fungicide in order 

 to obtain complete protection. If, on 

 account of delayed plant development, 

 this is applied April 15, four applica- 

 tions will be effective, and should this 

 be delayed until May 1, as was the case 

 in Hood River in 1917, three applica- 

 tions in many cases gave excellent 

 results. 



Discussions of Different Applications. 

 In connection with the different ap- 

 plications given in the calendar there 

 are a few important factors that should 

 be discussed somewhat at length; lack 

 of space prevents this in the tables. 

 For the sake of clearness, a discussion 

 of each application follows, the para- 

 graph number corresponding with the 

 spray number given in the calendar. 



1. Dormant Spray. The oil applica- 

 tion is a dormant spray and is only 

 advised in orchards where the leaf 

 roller is present. When used for this 

 insect it is incidentally effective in con- 

 trolling both San Jose scale and brown 

 aphis. However, under Northwestern 

 conditions, rains following the applica- 

 tion of spray within three to five days, 

 its effectiveness is greatly reduced. 

 Warm, settled weather conditions are 

 absolutely essential to insure the leaf 

 roller eggs being destroyed by the oil. 

 The best results have been obtained by 

 waiting until the buds are well swollen 



and the tips of the first leaves are just 

 beginning to show. For the control of 

 San Jose scale and oyster shell scale 

 lime-sulphur used 1-8 will be found 

 less expensive and more effective, pro- 

 vided rainy weather follows the appli- 



Ficube 1 — Delayed Dormant Spray. 



cation. If the lime-sulphur is used as 

 an early dormant application (before 

 the buds swell) use Rlack Leaf for 

 brown aphis control in Spray No. 2. 



2. Delayed Dormant Spray. The de- 

 layed dormant spray is primarily a scab 

 spray. Protection is needed at this time 

 as spores of the fungus are being dis- 

 charged in large numbers from the old 

 fallen leaves. In orchards where the 

 brown aphis is troublesome (the insect 

 which causes the small, knotty clusters 



Spray Program for Northwest Apple Orchards 



Application 

 Dormant Spray. 



2. Delayed Dormant Spray. 



3. Pink Spray. 



4. Calyx Spray. 



Ten-Day Spray. 



6. Thirty-Day Spray. 



7. July Spray. 



Insect and Plant Disease Material and Time of Application 



Tpaf roller For the leaf roller, miscible oil, 6 to 100. ... . c t „ 



Rrnw n aiihi's Use only in orchards where leaf roller control is desired or where San Jose 



San Jose scale. scale is serious. Apply as late as possible in the spring, under warm, settled 



Oyster shell scale. weather conditions. 



(See discussion for Spray 1.) 



Annie scab For scab, lime-sulphur 32°, 1 to 25.* 



Annie mildew For mildew, add iron sulphide mixture, 10 to 100. 



Krmvn anhis For brown aphis, add tobacco (nicotine sulphate) 1 to 1200. Apply at time the 



crown apms flrst , eaves are unfold j n g a bout the bud clusters on the fruit spurs. 



(See discussion for Spray 2.) 



1 to 30. 



Annie scab For scab, lime-sulphur 32°, _ 



Miklew "".'.. For mildew, add iron sulphide mixture, 10 to 100. 



Und moth " ' For bud moth, add arsenate of lead, 4 to 100 (powder 2 to 100). 



..j :„ .i,„ dusters (Figure 2). 



Do not apply 



Apply as soon as petals fall. 



until the fruit buds stand separated in the cli 

 (See discussion for Spray 3.) 



Annie scab For scab, lime-sulphur 32°, 1 to 35. 



Miklew For mildew, add iron sulphide, 10 to 100. 



Codlin" moth' ' For codling moth, add arsenate of lead, 4 to 100. 



Codling motn (See discussion for Spray 4.) 



Annie scab For scab, lime-sulphur 32°, 1 to 40. 



Mildew For mildew, add iron sulphide mixture, 10 to 100. Apply 10 to 15 days follow- 

 ing calyx application. (See discussion for Spray 5.) 

 ADDle scab For scab, lime-sulphur 32°, 1 to 50; or self-boiled lime-sulphur, 6-6-504 



For codling moth, add arsenate of lead, 4 to 100. 



For green and woolly aphis, add tobacco, 1 to 1200. Apply 30 days following 

 the calyx application. (See discussion for Spray 6.) 



Codling moth (if present) 



Green aphis 1 



Woolly aphis I 



(Advisable in certain sections 



Cnd/ine moth For codling moth, add arsenate of lead, 4 to 100. 



kS.»r, f nhU . . . ) For green and woolly aphis, add tobacco, 1 to 1200. In applying this spray con 



Green aphis 

 Woolly aphis 



} 



For green and woolly aph._, 



suit with your nearest expert. (See discussion for Spray 7.) 



Third Codling Moth Spray. Codling moth For codling moth, add arsenate of lead 4 to 100. 



For anthracnose and late scab, add bordeaux mixture, 3-4-50.+ 



Anthracnose 



Woolfv a anhis ' .' .' .' '.'.'.?.'. '■ '■ ■' •' •'• For woolly aphis, ac 



9. Fall Spray. 



If lime-sulphur does not test 32 



Anthracnose 



see accompanying table f 



ipplication can only be told by seasonal development of codling moth 

 breeding cage studies. Get in touch with nearest entomological m- 

 (See discussion for Spray 8.) 



Apply as soon as fruit is harvested. 



Date of a 



through 



vestigator 



For anthracnose, bordeaux mixture, 6-6-50 



t Write Oregon Agricultural College for particulars in the piepa 

 t Three pounds bluestone, four pounds lime, fifty gallons water. 



the proper dilution, 

 ration of self-boiled lime-sulphur. 



