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AMERICAN FORESTRY 



increased demand has been greater than the diseased wood could 

 supply. The result is a partial shortage of water supply among 

 the branches which causes the scorching to appear very suddenly. 

 This is the way the matter has been figured out by the specialist 

 on pine troubles, after a thorough investigation of the sap wood 

 and knowledge of the circumstances. We believe this diagnosis to 

 be true, although it is not possible with our present facilities to 

 actually prove it definitely by experiment. Records kept for 

 several years upon diseased trees showed that most of them recov- 

 ered the second year, and that only a relatively few died from 

 the effects. So far as we can judge, there is no treatment which 

 is likely to aid this trouble. 



Q. I am enclosing a bay leaf, from one of the ornamental 

 trees in our show-room. The tree is generally affected in this 

 way and we would like to know what to do for it. Will you be 

 good enough to advise? 



F. R. C, Hollywood, California. 



A. An examination of the bay leaf which you send shows 

 that the tree is infested with sucking insects. The leaves should 

 be washed, on the under side, with a solution of whale-oil soap, one 

 pound to ten gallons of water, or with a solution of nicotine or 

 tobacco dust. These insects are common on bay trees and the 

 treatment may have to be repeated many times in the future. If 

 washing the individual leaves is too big a task (depending on the 

 size of the tree), then apply solution by spraying. You will find 

 where the plants are kept indoors too much they are more likely 

 to contract the infection. 



Q. We have nine acres on the outskirts of Augusta, Georgia, 

 on which are growing some very beautiful trees. We have three 

 oaks, whose diameter will average about six feet, then there is a 

 sugarberry whose diameter runs about eight feet besides perhaps 

 a dozen wild olives whose diameters will run about three feet, 

 and a cherry tree with a diameter of about three and a half feet 

 and which is about one hundred feet tall. I mention these as an 

 indication of the very fertile soil upon which these trees are 

 growing. A few inches under the surface we have a red clay, 

 which, judging from the growth of the trees and vegetation in our 

 garden, must be well suited for plant life. On this place we have 

 two walnuts, black walnut. These trees will run something over 

 three feet in diameter and are very fine specimens, but for the 

 past several years we have noticed the ends of the limbs beginning 

 to die, and it is quite frequent that we find dead limbs of consider- 

 able size. Last week I happened to be up there and was talking to 

 two so-called tree doctors " and they both pronounced the ail- 

 ment " borers." They stated that same can be eliminated and 

 the tree cured by spraying. The cherry also has a good many 

 dead limbs and the men said that the same trouble was affecting 

 it. Of course, a tree the size of these cannot be effectively 

 sprayed, but is there not a wash that we can apply to the tree on its 

 trunk and larger limbs that would help? 



R. W. H., Savannah, Georgia. 



A. It is quite common for walnuts of the size of yours to 

 show dead ends. Sometimes the primary cause is old age and a 

 hollow trunk and sometimes boring insects. Old walnut trees 

 have a tendency to develop a decayed center and decayed pith 

 in main limbs. If borers are present, then there should be seen 

 on the outer bark a number of small, holes which lead to the 

 burrows of the grubs. In such cases, inject carbon bisulphid into 

 the burrow and clog the hole immediately after injection with 

 soap, so as to retain the deadly fumes generated by the carbon 

 bisulphid within the burrow. Under any conditions, spraying the 

 trees will not affect boring insects because the latter grub under- 

 neath the bark in the woody tissue and any application of poison 

 on the outside to the bark or the leaves will never reach them. 

 In the case of the cherry trees, if you see any gummy exudations 

 from the bark you may suspect the presence of boring insects 

 underneath the bark and the remedy in that case is to grub them 

 out with a penknife and remove the borer bodily. Injections will 

 not help because the gummy substance will not permit. the injected 



material to enter the burrow. The knife is best in this case and 

 here, too, do not spray if you are fighting a borer in the inner 

 wood. It may also be wise to " cut in " the branches of the cherry 

 to compact the crown. This will rejuvenate the tree and cherry 

 trees respond to the treatment. 



Q. I have a number of Silver Poplars on my place here that 

 are in some way affected. Many of the leaves are drying up and 

 falling off, others are turning yellow, and the tips of the new 

 growth are drying up and breaking off. I am sending you a couple 

 of these tips. You will notice in each of them is a spot where 

 they are broken and which appears to be stung by some insect 

 and each side of this sting the wood is dry for about one-quarter 

 inch. About a month ago I first noticed that the trees were 

 affected, and then discovered many small green lice under the 

 leaves. I sprayed the trees twice with arsenate of lead, but after 

 each application had a heavy rain. The lice now have disappeared 

 but the trees look badly. If you can inform me what is the trouble 

 ani how to overcome it, I shall be indebted to you. 



S. H. W., Guilford, Connecticut. 



A. An examination of the leaves you send shows that the 

 poplars have suffered from winter's frost and summer scorch, fol- 

 lowing frequent dampness. Last winter was a hard one on poplars 

 as well as on other tender plants. Hundreds of poplars have been 

 killed outright in Connecticut and in the vicinity of New York. 

 This summer there was a series of hot days following days of 

 extreme dampness, and this caused considerable scorch. Our 

 advice would be to "cut the trees in" this fall. Cut in very hard, 

 depending on the size of the tree. Cut off most of the ends and 

 altogether make the crowns of the trees compact and bushy. There 

 is no evidence of any special insect on the leaves. Whether there 

 are any borers in the branches, only an investigation would show. 



Q. I planted in my garden this Spring a number of fruit 

 trees, apple, plum, pear and peach. They took root and came 

 along well, but now the leaves are turning black and falling off. 

 On the stems there are " bunches " of small green insects. Can 

 you tell me what they are and what to put on the trees? 



F. N. H., New York City. 



A. Replying to your recent inquiry, the insects in question are 

 small thrips, quite common on the under side of leaves in the 

 summer time. Spraying the infested leaves, on the under side, 

 with whale-oil soap solution, one pound to ten gallons of water, 

 will destroy these insects. The season, however, is so far 

 advanced that it is hardly worth while spraying this year, and I 

 would suggest deferring it until early next summer. 



Q. I have two very fine horse chestnut trees on my farm 

 in Chester County which have just developed "rusty" leaves. 

 The leaves particularly towards the lower branches are turning 

 brownish, rusty and drying up. Can you tell me what to do? 

 Perhaps you can tell me what the trouble is. Shall appreciate your 

 advices. F. B. R, Haverford, Pennsylvania. 



A. It is quite characteristic of horse chestnut, both in this 

 country and abroad, to have their foliage turn brown early in the 

 summer. The cause is a fungous blight on the leaves. It will not 

 kill the tree and a close examination will show that the next year's 

 buds are already well formed. The direct responsible factor is 

 drouth and one will, therefore, notice more of this trouble on city 

 streets than on open lawn and more in dry seasons than at periods 

 when there is plenty of rain. Digging a shallow trench around the 

 tree a few feet away from the trunk and constantly filling it with 

 water will help to stay the difficulty. 



Q. What can I do for our maple trees? All over town they 

 are infested with tiny white cotton-like patches. 



M. H., Big Rapids, Michigan. 



A. Are they sugar maples or silver maples, and do the patches 

 appear on the twigs or the trunks? If they are sugar maple trees 

 and the patches are on the trunk, then the trouble is an insect and 

 the thing to do is to wash the affected parts with whale-oil soap 

 solution, one pound to ten gallons of water. If they are silver. 



