70 



ANNUAL REPORT 1920 AND 1921 



Practical Results 



Turning now from the field of plant physiology to actual results in the 

 orchard, we find that girdling avocados does throw them into bearing. The testi- 

 mony is unanimous on this point. I will have time to cite only a few of the 

 large number of growers who have been good enough to answer my letters. 



Mr. J. M. Elliott girdled a lot of Taft limbs in October. These limbs 

 all bore from ten to twenty fruits each with nothing on the remainder of the tree. 

 This year he has girdled a much larger number. 



On October 24, 1918, Mr. Whedon girdled 65 Taft trees. The fol- 

 lowing summer he sold 234 fruits from the girdled trees, and none from those not 

 girdled. It is interesting to note that even the next year the old girdles showed 

 results, and in 1921 the Tafts bore 120 fruits while those not girdled are still 

 bearing nothing. 



Mr. Wm. Hertrich girdled 25 seedling trees with the result that 75 % 

 of them blossomed and set fruit. At the ranch of Mr. Geo. D. Hoffman at 

 El Mirador, Mr. Dolman has gotten good results from girdling and is continuing 

 the work in an experimental way. 



Dr. Keller girdled one branch of a three year old Linda with the result that 

 the branch matured 38 fruits while only 2 were borne on the rest of the tree. 

 Mr. Rideout and a number of others have had very similar results. Mr. 

 Knight varies the process by using a binding wire instead of cutting out a girdle. 

 His results show some variation depending on the time the wire was left on. 

 Mr. Spinks uses the girdle extensively in propagating and top-working trees, 

 but not for fruit production. 



While practically every man who has girdled in October has gotten fruit, 

 a good many seem to think the procedure is dangerous on the ground that the 

 limbs may be weakened and break at the scar. No one cites instances of actual 

 loss by breakage, and I am inclined to the opinion that this fear is not justified. 

 Where the cut extends just through the bark and is quickly healed over, the 

 branch should not be weakened to any extent. 



Conclusions 



Girdling is inexpensive and brings big results. It has not yet been shown 

 to be attended with serious damage to the trees. The best time is October. 

 The best width of girdle varies with varieties from to ^4 inch. Suckers 

 arising behind the girdle should not be removed too soon. 



By way of suggestion I would like to point out that more experiments 

 should be made on root pruning. If a tree like the Taft persists in wasting its 

 substance in riotous living and refuses to take life seriously, might not a vigorous 

 root pruning furnish a sufficient check to vegetative growth to produce results 

 without the scarring incident to girdling? 



In closing I wish to thank the many avocado growers who, in response to 

 my letters, went to such pains to write me of their results. To them belongs the 

 credit of any value which may attach to this paper. 



