MAEKET DISEASES OF APPLES, PEAES, QUINCES 51 



CONTROL MEASURES 



Control measures that have been suggested are: (1) The use of 

 some other rootstock than the Japanese on which to graft pears; (2) 

 inarching to change the stock, especially of trees 2 or 3 j^ears old or 

 possibly slightly older, and (3) the improyement of soil conditions 

 where hardpan^is found, (i, W, 106, 107, 108, 109, 121, W, 2S8.) 



BLACK ROT 



(See Apples, Black Rot, p. 10 ; pis. 1, B, and 13, C) 



BLACK SPOT 



(See Quinces, Black Spot, p. 57; pis. 1. D, and 16, D, E) 



BLUE-MOLD ROT 



(Penioillinm expansum (Lk.) ex Thorn, and possibly other species) 



Blue-mold rot of pears (pi. 13, D) usually has the same symp- 

 toms as those described for the rot of the same name on apples. 

 There is a form, howeyer, known as pinhole rot, which in its early 

 stages appears as numerous minute spots of decay scattered oyer 

 the surface of the fruit. Infection apparently takes place at the 

 lenticels in the skin. As the disease progresses the spots increase 

 in size and finally coalesce, so that eyentually the fruit becomes 

 entirely decomposed. 



Pinhole rot occurs in both washed and unwashed fruit, but is 

 most serious on the Winter Nelis yariety. Other yarieties are some- 

 times attacked. Although exact figures are not ayailable as to the 

 amount of loss caused by this disease, the estimate has been made 

 that during the season of 1929-30 it depreciated the yalue of the 

 Winter Nelis tonnage from certain regions by at least $1 a box. 



Pinhole rot is most seyere in fruit that is ripened slowh^, hence 

 is probably best controlled by maintaining the fruit in a hard green 

 condition while in storage, and ripening it quickly upon remoyal. 

 (94, 100.) 



BROWN ROT 



(See Apples, Brown Rot, p. 14; pis. 1, D, and 13, E) 



BRUISING 



(See under Silicate Injury, p. 55, and pi. 17, A, B, C) 



CORE BREAKDOWN 



Core breakdown seems to be more serious in some localities than 

 in others, yet the trouble is more or less common to all pear regions, 

 and most yarieties of pears are subject to the disease. Clairgeau, 

 Clapp Fayorite, Boussock, Early Haryest, Guyot, Jargonelle, Le 

 Conte, Madeleine, and Sudduth haye been reported as susceptible 

 under New York conditions. Of the varieties grown in the North- 



