PROTECTIOlSr FROM THE LOCUST BORER. 5 



old waste land, the soil of which has been enriched by a thick bed of 

 humus beneath the trees. 



Another group (PI. I, fig. 2) near by contains about 30 trees similar 

 in respect to size and conditions. These have seeded the surrounding 

 soil so that a large clump is formed of dense growth, the outermost 

 being some 6 to 8 feet high. None of these trees have been injured 

 by the borer. A third group (PL II, fig. 1), forming a small oval 

 clump, contains 38 trees from 2 to 4 inches in diameter and 15 feet 

 high. They were closely set, averaging 4 feet apart. A few sassa- 

 fras were intermixed. In July, 1918, not one of these trees contained 

 a borer. August 20, 1918, the plot was thinned, all branches trimmed 

 to 8 or 10 feet, and all weeds and briers removed. The trees were 

 closely watched and many adults were observed ovipositing on them 

 during September.^ Adults were likewise observed on the isolated 

 trees near by, but none in the dense plats described above. 



6. A fence row opposite the eastern field station at Falls Church, 

 Ya., is densely matted with wild cherry, honeysuckle, and goldenrod 

 along the sides. Through this grow a dozen locusts (PL II, fig. 2) 

 2 to 4 inches in diameter. None of these trees were infested on or 

 previous to August 15, 1918, on which date all the surrounding 

 growth was cleared from four trees. During September adults were 

 observed ovipositing on these four. Many such fence rows exist 

 wherever locust is grown and explain why so little trouble is experi- 

 enced on the average farm, 



7. Along the south bank of the Potomac River between Difficult 

 Eun and Scotts Run many locusts are growing on the wooded slope. 

 This stand is a hardwood mixture composed chiefly of oak, chest- 

 nut, hickory, tulip tree, basswood, and butternut. All the locusts 

 are tall, straight poles, reaching to the top of the stand, the trees 

 averaging from 6 to 18 inches in diameter. All show a thrifty condi- 

 tion of growth and no borer defects. A low meadow, sometimes cul- 

 tivated but now pastured, lies between this river terrace and the 

 water. A few occasional locusts grow here, nearly all of which are 

 infested and badly deformed. No goldenrod occurs in the meadow, 

 and the adult beetles were observed to feed on several species of 

 Eupatorium. 



PLANTATIONS ALONG THE PENNSYLVANIA RAILROAD. 



From the office of the forester of the Pennsylvania Railroad rec- 

 ords have been secured of 42 plantations, comprising nearly 2,000 

 acres, on which over 1,000,000 trees were planted. These trees were 

 about 2 years old when set out and usually were spaced 8 by 8 or 8 by 

 10 feet. Many of these tracts were personally examined by the 

 writer, accompanied by Mr. I. T. Worthley, assistant forester. The 

 history of each plantation was ascertained as accurately as possible. 



1 Examination of this plot on Apr. 8, 1919, showed an average of 15 borers per tree. 



