gS AGRICULTURAL RESEARCH AND THE FARMER : 



isolated in pure culture and are now being studied, particularly 

 as regards the rate at which they are able to attack antiseptics 

 in liquid and soil under control conditions. This is clearly an 

 important factor in connection with the apphcation of volatile 

 antiseptics, such as naphthalene, to the soil. In glasshouses, 

 for example, soils are apt to become infested with harmful 

 organisms through intensive cultivation under semi-tropical 

 conditions, and applications of the disinfectant (cresol) are only 

 partially effective on account of its rapid disappearance. The 

 work has so far indicated a method by which this rapid disappear- 

 ance may be prevented, and this method is being further investi- 

 gated. It may be mentioned that an examination of nearly a 

 hundred samples of soils from different districts has shown that 

 the organisms which are able to decompose disinfectants are 

 widespread. 



A large number of chemical products have been tested for 

 their poisonous effect on soil insects and pests, and it has been 

 found that definite and important relations exist between the 

 chemical constitution and physical properties of the materials 

 studied and their poisonous action. The work is being continued. 

 In connection with this investigation it has been shown that 

 chloropicrin, for example, is most highly poisonous to wireworms 

 and eel worms. Owing to its disagreeable and poisonous nature, 

 however, great care is necessary in its use, and its utility is 

 probably limited to glasshouse work. 



Preliminary investigations have also been commenced on 

 fungicides. It is further proposed to study the chemical side of 

 the question of the immunity of plants from disease, which 

 may lead to results useful to the plant breeder. In this con- 

 nection special attention is being paid to wart disease of 

 potatoes. 



