790 EXPERIMENT STATION RECORD. 



According to the author, the tip burn, which was probably of a physiological 

 nature, served to reduce the vitality of the plants, making them subject to the fungus 



attack. When first noticed the mycelium of the fungus was only to be found in the 

 tips of the leaves which had tip burn characteristics. 



Later in the winter a second greenhouse was planted with lettuce, and in this ease 

 the plants nearly reached maturity before they were attacked by any fungus and 

 there were but few cases of the typical Botrytis present. The most injury in the 

 second experiment was done by the typical drop, Sclerotinia libertiana. When 

 attacked by this fungus the plants collapsed as though the stem had been cut off. 

 The fungus develops rapidly, and its occurrence in the soil shows that it can live 

 both as a saprophyte and a parasite. 



The author believes that there are two distinct species of fungi causing the drop 

 disease of lettuce, and expects to continue his observations on the disease during the 

 coming season. 



Apple scab, A. B. Cordley (Oregon Sta. Rpi. 1904, pp- 38-40). — An account is 

 given of some experiments in spraying 400 Newtown Pippin trees with Bordeaux mix- 

 ture for the control of apple scab. The orchard was sprayed five times with a 4-4-50 

 solution of Bordeaux mixture, the applications being made on April 30, May 14-10, 

 June 1-3, July 1-3, and August 15. 



The fruit when gathered was carefully inspected and separated into classes, and it 

 is stated that the sprayed trees bore approximately 10 times as much fruit free from 

 seal) as the unsprayed trees, or, while the unsprayed trees produced fruit only 7 per 

 cent of which was free from scab, the sprayed trees produced a crop 70 per cent of 

 which was free from disease. 



Discovery of a fruiting stage of the apple mildew in England, G. Massee 

 (Gard. Chron., 3. ser., 36 (1904), No. 934, p. S49,figs. 2).— The apple mildew (Sphse.- 

 rotheca mali) has been well known in England for many years, but until the present 

 season the ascigerous or fruiting form has not been reported. Specimens were sub- 

 mitted to the author in which the fruiting form was discovered on adventitious 

 shoots springing from the base of the trunk of an old apple tree. 



The use of sprays and dry sulphur powders seems to have little effect on this fun- 

 gus, and it is recommended that all diseased tufts of leaves, together with a portion 

 of the shoots, be cut off and burned. 



Black spot canker, W. L. Lawrence ( Washington -SYo. Bid. 66, pp. 35, pis. 13).— 

 The black spot canker is said to be one of the most important and destructive 

 diseases in the State and has been under observation since the summer of ,1902. The 

 results of the investigations are given in detail. 



The disease, which is known by a number of names, is attributed to the fungus 

 Gloeosporium malicorticis. So far it has not been reported from any other host than 

 the cultivated apple tree, but as similar canker diseases are found on other species 

 of trees, it is possible that some relation may yet be established between them. All 

 varieties of apples seem to be susceptible to the attacks of the fungus, although some 

 are more frequently attacked than others, and there is frequently a difference in the 

 susceptibility of a variety in different localities, even when grown under nearly the 

 same conditions. 



The amount of injury done is difficult to estimate, since trees may be badly affected 

 and still produce a partial crop of fruit. However, when the canker has become 

 very numerous the tree is weakened and after a while destroyed. Trees whose bark 

 has become well developed and has assumed a heavy corky layer are immune to the 

 disease. 



Contact inoculations showed that the fungus is able to penetrate the smooth 

 uninjured epidermis of young branches and twigs, and other experiments showed 

 that it also entered through the lenticels and through various mechanical injuries done 

 to the trees. 



