CONTRIBUTIONS FROM THE WISLEY LABORATORY. 



511 



a very considerable extent, and at the same time it may be used against 

 this fungus with hope of success. The spraying should be done at least 

 three times — once after the buds burst but before the flowers open, once 

 after the petals are shed, and a third time about three weeks later. The 

 Bordeaux mixture should be only half the strength used in spraying 

 potatos. It is evident also that clean culture will reduce the number 

 of spores floating in the air ready to attack the leaves. 



Summary. 



1. The blotching and " scorching " of apple leaves has been extremely 

 prevalent during the season of 1907. 



2. In almost every case examined the scorched spot has been produced 

 by the fungus Cladosporium herbarum. 



3. The presence of the spots offers a menace to the health of the tree, 

 since the effective leaf area is very greatly diminished by their presence. 



4. Various causes have been suggested to account for the spotting of 

 the leaves, but it is shown that it could not have been directly due to the 

 influence of the weather, since none of the climatic factors capable of 

 causing the spotting differed materially from those of the preceding years 

 when the spotting was not prevalent. 



5. The weather had been such, however, as to cause somewhat abnormal 

 growth, and to lay the foliage open to the attack of certain fungi. 



6. Some varieties of apple are apparently more liable to the attack 

 than others. 



7. The best method of prevention lies in the direction of checking the 

 germination of the fungus spores by means of such a spray as dilute 

 Bordeaux mixture. 



II. A Disease of the Cineraria. 

 By Fred. J. Chittenden, F.L.S. 



Unlike the majority of plants cultivated on an extensive scale in 

 this country, whether under glass or in the open, the Cineraria has so 

 far been remarkably free from the attacks of fungi. Dr. Cooke in his 

 " Fungoid Pests of Cultivated Plants," p. 52, alludes to only one, 

 Aecidium Cinerariae, as attacking the Cineraria, and that " has [recently] 

 been detected in Austria on leaves " of that plant. A second fungus is 

 reported in Tubeuf and Smith's "Diseases of Plants," viz. Bremia 

 lactucae Reg. As the last fungus is common on lettuce and sow-thistles, 

 as well as on some other native plants, we may expect to find it on 

 Cinerarias from time to time. Massee in his " Text Book of Plant 

 Diseases," p. 242, in discussing the Chrysanthemum rust, suggests that 

 " there is no reason why the fungus (Puccinia hieracii) should not, in 

 course of time, attack other cultivated composite plants, as Cinerarias, 

 Dahlias, &c," and this is the only mention made in that useful work of 

 a fungus even probably to be found on the Cineraria. It may be worth 

 pointing out that the Puccinia on Chrysanthemum is now regarded by most 



