1670 



ENCYCLOPEDIA OF PRACTICAL HORTICULTURE 



PECAN DISEASES ' 



Frozen Sap Ulifrlit 

 This term has been applied to the in- 

 jury done by frost to one-year grafts. 

 Generally a dead spot appears in the 

 trunk of the trees. Three and five-year 

 trees are killed by this freezing. These 

 four to six inches in diameter generally 

 stay dormant. In grafted trees buds have 

 been successfully inserted about one foot 

 above the ground. 



Pecan Leaf Blight 



Cerospora halstedii 



This disease of pecan leaves causes 

 them to turn brown, wither up and drop 

 prematurely. At first, small brown spots 

 are noted. These become larger, and at 

 length the whole leaf is destroyed. When 

 attacked by this disease, the tree makes 

 no progress. An examination of the dis- 

 colored areas, under the microscope, 

 shows the presence of tuft-like growths 

 of spores upon short conidiophores. As 

 they become matured, the spores are scat- 

 tered by the rain or wind, and so the dis- 

 eajse is spread. It probably lives over 

 from one season to another on the dis- 

 eased leaves. 



This disease is essentially a trouble 

 found among nursery seedlings and the 

 author has not noted its doing serious 

 damage elsewhere. After the trees are 

 grafted or budded, they do not appear to 

 be affected by it. The destruction of the 

 leaves of the seedlings Interferes seri- 

 ously with their growth, and it is best to 

 protect them against injury by spraying 

 with Bordeaux mixture. The first applica- 

 tion should be given just when the leaves 

 are expanding, and as each new set of 

 leaves starts out, another application 

 should be given. The 4-4-50 Bordeaux 

 formula has been found very effective. 



A power sprayer which will cover four 

 rows is most economical, if large areas 

 are to be sprayed. Sprayed seedlings will 

 make practically double the growth of un- 

 sprayed. H. H. Hume, 



'flip Ppoan and Its Culture. 



Bosette 



This is undoubtedly the result of an un- 

 balanced condition of the tree which is 



not able to properly assimilate its food. 

 It is not a bacterial disease, as plant 

 pathologists have never been able to in- 

 oculate the germs into an uninfested tree 

 successfully. It is found in both wild or 

 native trees and the budded and grafted 

 varieties. 



In appearance it resembles a miniature 

 shrub rising from the branch of the tree. 

 The stems and leaves in the cluster are 

 small and delicate. 



Scab 



Fusicladium effusiim Wint. 



Some varieties are more susceptible 

 than others and when it shows up badly 

 in an orchard the trees should be top- 

 worked to a more resistant variety. 



Scab causes circular black spots on the 

 leaves which fuse together. It also at- 

 tacks the young twigs. It appears to at- 

 tack the trees worse which are in low 

 ground and is most injurious during very 

 wet seasons. There has not been enough 

 work done to determine the best dates for 

 spraying. The difficulty arises in the ir- 

 regular blooming, causing several spray- 

 ings to be necessary in a mixed orchard. 

 P. F. Williams, 



Auburn, Ala. 

 Winter-Killing 



Trees which have a thick rough bark 

 generally escape from this. It has been 

 avoided by planting seedlings in bottoms 

 and top-working them when five Inches 

 in diameter. Four-inch trees do not 

 winter-kill. In trees in which the sap 

 rises first there is the greater danger. 



PECAN PESTS 



Apple Twig Borer. See Apple Pests. 



Case Worm. See Pecan Bud Worm, this 

 section. 



Cottony Cushion Scale. See Orange 

 Pests. 



Fall Web Worm 

 Hyphuiitria cunea Dru. 



An insect that becomes, at times, a very 

 serious pest to pecan trees by eating the 

 foliage is the fall web worm, so called. 

 This is the insect that builds so many 

 large and unsightly webs on many forest 

 trees, notably iiersimmon, hickory, wild 

 cherry, ash and others. According to 



