■~ ' 08 



llir(my;li(»uL Lli»! spriiii;, tlirou.uli I Ik- li<>i <li-v weuUit'i' of early 

 July, and the droiiiiiit of July and Anuusr. In early Septend)er, 

 two days al'lcr Hie almost niil>r(»ken week of raiii dnriiiii I lie lat- 

 ter ])arl of An^ust, these fhi})S were again examined, and on a 

 few of them which were eomposed entirely of bark, two or three 

 iiiehes long and half as wide, many spore threads were loniid. 

 These, rememl)er, from ehii)s that had been lying on the ground 

 for more than live months through the hot snmmer dronght. Pos- 

 sibly this may be regar<led as an extreme ease, l)nt in any event 

 it (dearly emphasized the necessity of extreme care in destroying 

 all diseased bark, clii])s, etc., in all attempts to control the dis- 

 ease. Again, extreme cases of the sort mentioned are often the 

 ver}'^ ones that junst be guarded against. In certain instances a 

 gasrdine torch has proved an eflficient adjunct for the burning out 

 of the diseased spot and thus destroying the fungus, whether or 

 not followed by the gouge and mallet. 



(5). Insects. 



Soon after beginning work on the disease in IDOS, our atten- 

 tion was irresistibly drawn to the evident intimate relation that 

 insects bore to the spread of the disease. It is singularly inter- 

 esting to note tliat i»ractically every i)erson wlio has been work- 

 ing on the disease in the field for any length of time has, sooner 

 or later, been strongly impressed with this very apparent inter- 

 ndationship between insects and the chestnut bark disease. Ter- 

 sonally, we have made many observations upon the tojdc, but as 

 this woi-k ])roi)erly l)elongs to another IJnrean of the V. S. I)ej)t. 

 of Agriculture, we have limited our work to observations. Here 

 is a phase of the work that c )uld easily influence the i)lans of 

 control to a large extent if we knew absolutely the ndation of 

 insects to the disease. It is gratifying to know that the Commis- 

 sion has an expert entonudogist already at work on this ]»articu- 

 lar part of the general prol)lem. 



(G). Immunity. 



From what is now known regarding the spread and virulence 

 of the Chestnut l>ark Disease, there seems little immediate 

 promise of individual trees or variations of the American Sweet 

 riiestnut (Ctistaiint drutafa) dev(do])ing immunity. As this 

 species is the only forest tree of the genus in the country, it 



