ccjTrll g^' P;{1::-!?ah-/est drop cf apples 



As you all know, I^clntosh is a variety which is outstanding in its suscepti- 

 bility to pre-harvest drop. This drop is usually more severe on trees which are 

 hi^h in nitrogen due to heavy applications of commercial nitrogen fertilizers or 

 mulch. Also trees v^hich have poor foliage due to the activities of mites and other 

 insects or as a result of frost, are subject to much heavier fruit dropping than 

 trees with healthy foliage. 



Materials for delaying pre-harvest drop in the Northeast consist of naphthalene- 

 acetic acid type materials and have been in general use for 8 or 9 years. It is 

 possible that we may have other materials shortly v;hich may be superior to any 

 material now available, but they are still in the experimental stage. These 

 naphthaleneacetic acid type materials should be applied as soon as the first sound 

 fruits commence to drop. Apples which have insect damage, scab, or are lopsided 

 from lack of seeds should be disregarded; they will drop anyway. It may be 

 desirable for a grov/er to clean up drops under a fevi typical trees in advance so 

 that he can follow the drop daily and determine accurately v/hen the first sound 

 fruit has commenced to drop. Timing is extremely important . An application put on 

 too early or too late is apt to give very disappointing results. 



Most materials are put up so that h ounces of the material per 100 gallons^ 

 will result in a 10 parts per million concentration (single strength). An appli- 

 cation of this concentration may be expected to delay drop about 7 days . In order 

 to delay drop 10 to 12 days , a second single strength application^may be necessary 

 £ days after the first one . The use of 2 or 3 times this dosage (double and triple 

 Strength) may be effective up to 10 to 1^ days' , with only one application . A 0.1^ 

 dust is equivalent to a single strength spray. Applications put on in warm weather 

 ^\dll become effective somewhat sooner than applications put on in cool weather. 

 Under severe drought conditions, such as we are now experiencing, the hormone may 

 be ineffective. A heavy rain will be necessary in many orchards before harvest _in 

 order to supply rieeded water, or the material may be of very little value in ^: 

 delaying drop this year. , . 



Thoroughness of application is, of course, important. It is necessary that the 

 foliage be well soaked with spray since it is through the leaves that the material 

 is absorbed, ^^etting of the stems of the fruit is not of primary importance, as 

 once supposed, since it has been found experimentally that injections or applica- 

 tions of this material to the foliage alone are effective in delaying the drop. . 



— F. W. Southwick '■ 



JC J J. j<. J J. 



Pre-Harvest Suggestions for the Apple Grower . 



(1) Observe Mcintosh drop daily on a few trees to determine time for 

 hormone application. 



(2) Check supply and condition of picking equipment, - ladders, picking, 

 containers, boxes, etc. 



(3) Smooth and otherwise level orchard roads to prevent bruising of fruit. 

 (U) Recruit and train supervisors of picking crews. 



(5) Observe where your best and poorest fruit is produced . as a guide to 

 your pruning, mulching, spraying and thinning program in 1550. 



