leaf scorch on pear 

 ginal coloration of 



- 9 



is almost black in comparison to ash gray mar- 

 K-deficient apple foliage. 



We now believe that pear psylla are frequently associated with 

 the scorch of pear foliage because of their presence on tne leaves 



having the disorder in 1970 and 1971. Honeydew secreted by these 

 insects adheres to the foliage and a sooty fungus grows in it. The 

 foliage with the sooty fungus is injured. 



*************** 



MANGANESE DEFICIENCY 



William J. Lord and John H 

 Department of Plant and Soil 



Baker 

 Sci ences 



This past summer we observed, for the first time, what ap- 

 peared to be manganese (Mn) deficiency in several apple orchards 

 and one peach orchard. Leaves had interveinal fading of chloro- 

 phyl 1 , starti ng at the 

 leaf margin and ex- 

 tending towards the mid 

 rib (Fig . 1) . To verify 

 our observations, leaves 

 from Mcintosh apple trees 

 in 3 orchards were anal- 

 yzed and their Mn content 

 was found to range from 

 9 to 14 ppm. Mn levels 

 of this magnitude are 

 critically low in compar- 

 ison to the desired stan- 

 dard of 50-100 ppm set by 

 other states for apple 

 trees . 



The peach orchard 

 also was low in Mn. ' 

 Leaves from trees showing 

 the deficiency symp- 

 toms had 13 ppm Mn in 

 comparison to 97 ppm 

 in leaves from trees 

 with no interveinal 

 1 OSS of chlorophyl 1 . 



Fig. 1. Mcintosh apple leaf showing Mn 

 deficiency . Note the interveinal fading 

 of chlorophyll with the veins remaining 

 green. (Photo by L.J. Musante) 



Mn deficiency can be corrected by foliar applications of man- 

 ganese sulfate or of a fungicide containing Mn. For apples, Dr. 



