FRUIT THINNING WITH CHEMICAL SPRAYS 



31 



Table 9. — -Effectiveness of thinning sprays on several peach varieties, 



1942-49— Continued 



Variety 



Age 



of 



trees 



Year 



Treat- 

 ment 



Concen- 

 tration 

 per 100 

 gallons 



Blos- 

 soms 

 open 

 when 

 sprayed 



Blos- 

 soms 

 setting 

 fruit 



Yield 

 per 

 tree 



Fruits 

 per 



bushel 



State and 

 literature 

 reference 





Years 



6 



1948 



1949 

 1949 



1949 

 1949 



[Check 2 _ 

 Elgetol- 



L-do.__ 

 Check i"_ 

 DNNo. 



- 1. 

 DNNo. 

 289. 



.'Check i. 

 DN No. 



• 1. 

 DN No. 



289. 

 Check 2 _ 

 ElgetoL. 



___do.__ 

 ___do_._ 

 ( ___do.__ 

 Check 2 _ 



• ElgetoL- 

 do.__ 



Quantity 







Percent 



Percent 



63 



28 

 47 

 64 

 24 



16 



36 

 15 



11 



54 

 48 

 45 

 58 

 55 

 50 

 33 

 35 

 33 



Bushels 



Number 



Wash- 



Hale- 



1.5pt.__ 

 1.5pt__. 

 



85 

 100 







r i n §" 



haven . 







ton. 













,71b___ 



.7pt__. 







95 



95 









Do_ 







[New 

 ' York. 





9 



7 













.71b___ 



.7pt._. 







95 

 95 









Raritan 

 Rose. 







• Do. 













1.0pt_._ 

 2.0pt__. 

 1.0pt_._ 

 2.0pt__. 

 2.0pt__. 

 



75 



75 



100 



100 



( 3 ) 















"VY ash- 



Elberta _ 







mg- 









ton. 

















< 



Hale- 



1.0pt___ 

 2.0 pt— 



85 



85 







\ Do. 



haven. 

















1 Not thinned. 



2 Hand-thinned after fruit-set counts were obtained. 



3 Treatment applied at petal-fall stage, 3 days following full bloom. 



iii the initial set by bloom spraying seems to have enabled the trees 

 to differentiate more fruit buds for the following year. 



EFFECTIVENESS OF CHEMICAL THINNING SPRAYS 

 ON PEACHES 



Mature peach trees of good vigor generally present a thinning 

 problem in orchards where fruit buds have not been damaged by 

 winter temperatures and in areas where injury from spring frost is 

 of little concern. Most of the commercially important peach varieties 

 are self -fruitful, and with favorable bloom weather many varieties 

 set excessively heavy crops that necessitate thinning in order to attain 

 satisfactory size and quality. 



Dinitro Thinning Sprays 



The results with dinitro bloom sprays for thinning peaches have, 

 in some cases, been rather variable. With vigorous mature trees, the 

 failures have been due more often to insufficient thinning or no thin- 

 ning rather than to overthinning, Overthinning has occasionally re- 

 sulted on young trees or on mature trees that have failed to set 

 heavily because of certain environmental conditions. 



