Two Diseases of Pines 231 



One condition, which is absolutely necessary for the growth of the 

 ■"damping off" fungus, is an abundance of water. Warm, sultry days, 

 such as we frequently have right after a rain, are especially favorable, 

 and it under these conditions that we have the greatest loss of seedlings 

 from "damping off." Anything which tends to dry the surface soil 

 retards the progress of the disease; therefore frequent stirring of the 

 soil, accompanied by the admittance of air and sunshine has a good 

 •effect. Good results are also obtained by covering the surface of the 

 soil with a thin layer of sand or gravel. This prevents the soil from 

 coming into contact with the stem at the place where it is most liable 

 to attack. Spraying with Bordeaux mixture has been tried at Halsey, 

 "but with poor results. 



After a plant is once attacked, there is no remedy; therefore the 

 only means of combating the disease is by preventative means. In the 

 first place, the site selected for a seed bed should afford good drainage. 

 The best soil is a light, sandy loam; heavy soils containing a great deal 

 of organic matter, and which retain a great amount of water should 

 be avoided. A heavy soil may be improved, however, by mixing to the 

 depth of five or six inches with sand. After the seedlings come, up, the 

 soil should be kept well stirred to the depth of about one inch, unless 

 a surface mulch of sand or'gravel is used, in which case cultivation will 

 be unnecessary. On the forest reserve at Halsey, the beds are raked 

 immediately after every rain during the early part of the summer. This 

 is possible only in a light, sandy soil, such as is found at Halsey, since it 

 will not bake when worked wet. A sand or gravel mulch is to be rec- 

 ommended for a soil which can not be readily worked when wet. If 

 low shade frames are used, they should be raised after a rain, so as to 

 allow a free circulation of air. 



THE "LEAF" DISEASE. 



What seems to be a comparatively new disease has caused a con- 

 siderable amount of damage to the one- and two-year-old pines at 

 Halsey during the past two years. The presence of the disease is first 

 indicated by the dying back of the leaf tips during the early part of 

 summ.er. As the season progresses, the disease passes down toward the 

 base of the needle, often killing all of the needles and even the upper 

 portion of the stem. While the disease is doing a great deal of damage, 

 the present indications are that some of the attacked seedlings will 

 recover. A large number of the two-year-old seedlings at Halsey, which 

 died back almost to the ground last season, have sent out strong lateral 

 shoots this year. Whether they will recover, or whether the new shoots 

 ■will also be killed back, remains to be seen. 



