FRUIT WOTjIS - January, 1S4-0 



■tf. H. T-ies 

 ■i^r.tension -horticulturist 



_Int_er_nal_ _Corj^ P±_J^2J:es^,rK\_l;l^^Go:rtrol w'itli Boron 



The prevo-lence of internal cork in a^rples in 1939 v;as related to 

 the shortaije of rainfall, according to A. B. Burrell of Cornell University. 

 The effect of drouth, however, is an indirect one, probably opcratin-^ throu[;h 

 a reduction in the absorption of boron. \Je are indebted to Dr. Burroll for 

 the follouin™ recommendations. 



Insurance against a reciu're::ce of internal cork is bobt obtained 

 through application of boreix to the soil in a ring beneath the tips of the 

 branches. The fine granular fori", is best suited to the purpose, being lowest 

 in jrrice, easily spread, a:id not so subject to for;.j.ng hard lunps as the 

 pov/der forn. Application of straight bora;: v;ithout dilution is preferable 

 to i-dxing it with other ;uaterials, or depending on the boron in fertilizer 

 r.iixtures. 



It is custonary to irake cor.nnercial app:lications at the sa.uG tiue 

 as nitrogen fertilizers are put on, i.e., around tlie ti;.ie of the delayed 

 dorasirc or early pre-pink sprays. Provided the i.iaterial is ¥/ashed into -the 

 soil a fe\-f v/eeks before the appearance of synptorjs, aiiy date during the grov/- 

 irig season seei":s satisfactory. Application of bora:c to trees whose fruits 

 showed sone external cork on June 30, 1S39, greatly reduced the developi.ient 

 of internal cork during the bala-ice of the sur.X;:er. On the untreated trees 

 in this e::peri;?.ent, late-season internal cork was severe. Late fall asid 

 v/inter are considered undesirable -'c±::es for applying bora;: sending furth-er 

 study. 



The followiiig I'ates ox application have been found satisfaotorj- 

 under a wide range i:i soil co:iditions i;i tlie uajor fruit-growing districts 

 of I'lev/ York State. The availE.ble . evidence indicates thr.t one borax traatiAsnt 



A;:,jrox. trunk diaiJ° 1' above ^rpj-li^^. ^■^.-. A^.-'.^. fP^. rJ-ytIL3(^'2?-ip^rJ-PP,S'I}-. soil 



Up to 2v- iiiches 



3t 



5 



7 

 10 

 14 

 15 " up 



(Tlie size of a tree is nore dependable than the age for deter..n.n^n^, u. aui: 

 needed.) 



lasued by the iixtension Service, V/illard A. Lunson, director, in further- 

 ance of Acts of Jf''!ay 8 a::d June 30, 1914, I--assachusetts State College, United 

 States Department of Agriculture, and Cou:ity ^^xtension Services cooperating. 



