92 



Fruit suffered perhaps less from fungus diseases than usual. 

 The distribution of American Gooseberry Mildew, which in 1917 

 was extremely limited, increased materially, and, as was to be 

 expected, radiated out from the centres where it had occurred 



that year. 



Another contrast was found in the case of Black Currant Rust 

 (Cronartium vibicola), the general occurrence and abundance of 

 which, in 1917, was phenomenal. In 1918 the rust, except 

 when in immediate proximity to diseased Weymouth pine (its 

 alternate host), was absent. In autumn the disease! spread 

 somewhat in a few localities, but probably in all cases starting 

 from the infected pine centres. 



With regard to vegetables, during spring darnping-oif of seed- 

 ling tomatoes through a species of PhytophtJiora caused still 

 further damage. Sterilisation of soil and the use of non-con- 

 taminated water have proved successful as control-measures. A 

 leaf-blotch in cucumber, due to Collet otrichum oligoGhpetum, 



was estimated to cause a loss of several thousand pounds in 

 Hertfordshiie, in which county also Sleeping Dispose of tomatoes 

 is still very prevalent, destroying many thousands of plants. 



Onion Diseases, — Onions received special attention. The 

 Sclerot ium disease, which has been under research for more than 

 a year, proved very destructive last season and was discovered 

 to exist in practically all parts of England. It was observed at 

 Kew to attack shallots which hitherto were regarded as being 

 immune (see under "Research," p. 96). Another serious and 

 new disease, viz., Onion Smnt (Urocystit Cepulae), occurred in 

 two districts (Northamptonshire and Northumberland). This 

 fungus is the cause of much damage in the United States; it 



5 also on the continent of Europe. Although no published 

 record of the presence of Onion Smut in Britain exists it was 

 ascertained that the disease appeared near Edinburgh *seven 

 years ago but has been stamped out. The fungus has again 

 established itself in Britain (probably being re-introduced wjth 

 the seed), and every effort is being made to exterminate it. 



OCCUI 



Advisory Work. 



Advisory work covered a large range of diseases and was 

 particularly heavy in late spring and early summer. Owing 

 to all questions relating to potato diseases being dealt with by 

 the Food Production Department, the laboratory was relieved 

 of at least 500 enquiries with regard to this crop. The number 

 of enquiries dealt with was 730. Although most of th e were 

 answered by means of correspondence, in several cases visits 

 were paid with profitable results. Seme fifty visits to all parts 

 of the country were paid during the course of tin season. Some 

 of the more important cast s were Yellow "Rust in Wheat, Failure 

 of Oats, Bailey Stripe, Wart Disease of Potato, Potato Black- 

 leg 1 , Apple Mildew, Apple Canker, Weymouth Pine Blister En>t, 



Sclerotium Disease of Onion, and the newly-introduced Onion 

 Smut. 



Special visits were paid to a large number of orcharcl> in the 





