46 FIRST REPORT OX ECONOMIC BIOLOGY. 



During the present year I have seen a large number of houses of 

 cucumbers attacked at Waltham Cross, and have examined very badly 

 infected specimens of tomato plants from Hertfordshire. This dis- 

 ease having appeared in these three widely separated counties, there 

 is every probability that it is present elsewhere, and that many of the 

 numerous cases of wilting which have occurred during the past season, 

 and which have been ascribed by ignorant persons to eelworms, are 

 due to this disease. 



Dr. Grossenbacher's experiments show that inoculations made in 

 the open were almost failures, the moist, warm conditions obtaining 

 under glass being the essential and all important factor for the infec- 

 tion and development of the fungus. 



In addition to the muskmelon, the cucumber, West Indian 

 gherkin, Boston Marrow Squash, pumpkin, and two species of gourds 

 were infected, but the fungus had no effect on any but one of the 

 gourds, although it was able to vegetate and fruit on the dead vines 

 of other species. 



PREVENTIVE AND REMEDIAL MEASURES. 



Wherever the disease appears the haulm should be sprayed with 

 Bordeaux mixture ; this should be repeated at intervals until the fruit 

 is gathered, and then the whole of the haulm burnt. 



Before removing the soil from infected houses it should be treated 

 with a liberal application of ground unslaked lime. The same soil 

 should not be used again for two or three years. 



Grossenbacher (loc. cit.) has shown that the spores are not killed 

 by exposure to the weathering conditions of winter. The disease, he 

 states, may readily be prevented in the greenhouse by spraying 

 thoroughly with Bordeaux mixture, w T hen the plants are about half- 

 grown (i.e., before the disease appears), and repeating the applications 

 often enough to keep them covered with the sprayfluid. 



Good ventilation, so seldom present, is all important. 



POTATO SCAB. 



Ocspora scabies, Thaxter. 



This disease, of which there has been a large amount in the 

 Midland Counties during the past year, causes very little damage to 

 the potato Itself. It attacks the young tubers, and forms rough, scab- 



