86 



MART LAND AGEICULTURAL EXPERIMENT STATION. 



bage crop. I strongly recommend this course as one of the most prom- 

 ising, and where mnstard plants are not available or haAe not been pro- 

 vided, the best remedy to be applied is to spray Avith a pretty strong kero- 

 sene emulsion. 



APPLE-TEEE BORERS. 



There are two borers which seriously effect the apple tree in Maryland, 

 as they do, in fact, in almost all great apple-growing regions in the coun- 

 try east of the Rocky Mountains. These are, the Round-headed Apple- 

 tree Borer {Saperda Candida L.) and the Flat- headed Borer {Chrysobothris 

 feworata F). The former is by far the most frequent and injurious. 

 Both affect the trunk and usually the lower part, but they differ in their 

 mode of work and in their life-habits. 



The Round-headed Borer is the larva of a rather handsome long-horned 

 beetle with a number of grayish-white longitudinal stripes (Figure 17 c.) 

 The female lays her eggs in the month of June, in the trunks of not only 



h c 



Fig. 17.— Sapertia candidn; n, larva: b, pupa; c, Imafro. 

 the cultivated apple, but of wild crab apple, haw, pear and quince. As I 

 pointed out in 1877 she makes with her jaws an incision in the bark, 

 causing it to split open from one-third to half an inch in length, and 

 thrusts the egg between the bark and the liber at right angles to the side 

 of the slit, accompanying the egg with a gummy fluid which covers it and 

 secures it in place (Fig. 18 <r). The egg (Fig. 18 d,) is pale rust 

 brown in color, elongate ovoid, somewhat flattened and three millimetres 

 long. I'he young larva hatches in about two weeks and for the first year 

 anda-half of its life lives in the sap Avood, excaA'ating shalloAV cavities, 

 visible only by a slight discoloration of the bark and by a small quantity 

 of sawdust-like castings, Avhich issue from the original hole of entrance 

 or from cracks in the bark. During the third summer it generally com- 

 mences to cut cylindrical passages up into the Avood of the tree, not in- 

 frequently perforating it. It then rests in its burrow through the third 

 Avinter and transforms to pupa (Fig. 17 ^,- 18 .^,) in the spring, issuing 

 as a beetle during the late spring or early summer. 



