G7 



lll(»|-('o\c|-^ lIlclT is (lie a<l(lit iolKll <l;iin;r|- of iiilVrljoii ll-uin i\\(i 

 spitrcs <>r J Hd/iordic /nii n.sil ica. Jii oi-dci* lu i-ciIikm; \\i(t chainjus 

 of inrcctioii fi-oiii w (1(1(1 lotiiiiL; ;ni<i oilier riiii«^i, it has Imm.-ii lli(i 

 prevail in,:; cu.sloiii loi- many yeai's hi this couiilry as woil as 

 abroad, to paint all exposed surlaces of wood with tar or lead 

 [»aint. Jndj^ing Ironi onr own experience perhaps these are as 

 liood general pi'eparal ions for this [uirpose as any that we care 

 to reconiniend at this time, tlionj;h they are not ideal and they 

 do not prevent the checking of the wood. Morever, they mnst 

 he renewed from time to time in order to accomplish i)ermanent 

 good. Creosote is excellent for a preliminary coating, hnt it 

 sinks into the wood readily and a])parently has waterproof qnali- 

 ties of only temporary valne. It shonld always be followed 

 (within a few days, for example] with some thick or heavy coat- 

 ing, such as tar or paint. 



For preventing the drying back of the camhinm layer at the 

 edge of a cnt, we have so far found nothing better than orange 

 shellac. This does not long remain a waterproof covering under 

 ordinary conditions, and should, as in the case of creosote, be 

 covered with a lieavy coating of paint or tar, say >\ ithin two or 

 three weeks after it is applied. ^Many other preparations for 

 covering exposed wood have been tried, but those mentioned ap- 

 pear to have been the most satisfactory from the point of view 

 of our experiments on ornamental and orchard chestnut trees. 



(4). Sanitation. 



In cutting out diseased spots in the trunk or branches of 

 chestnut trees, the chips should be carefully gathered in papers, 

 or better, paper bags, and destroyed by burning. They should 

 not be left scattered about on the ground. In other words, sani- 

 tation is one of the essentials for success in this kind of work, 

 just as it is in the case of diseases of human beings. In all of 

 our experiments with the disease on one particular plot the 

 chips were left where they fell. No attempt was made to de- 

 stroy them. Later many of these chips were examined and a]»- 

 parently good, though dormant, fruiting pustules were present in 

 the majority of cases. To take one particular case : In March, 

 1011, some diseased spots, with good fruiting pustules, were cut 

 from a chestnut tree and the chips left on the ground in a sunny 

 exposed place on a dry hill-top. These remained on the ground 



