56 



DISEASES OF ECONOMIC PLANTS 



by him to disinfect nematode-infested soils in Florida. 

 The apparatus consists of a galvanized iron pan, 6 by 10 

 feet and 6 inches deep, which is inverted over the soil to 

 be disinfected, and the steam admitted under pressure. 



Fig. 17. — Disinfecting with steam by the inverted pan method. After Gilbert. 



The pan is suppUed with steam-hose connections, has sharp 

 edges, which are forced into the soil on all sides to prevent 

 the escape of steam, and is fitted with handles for moving 

 it from place to place, the weight of the entire pan being 

 not over 400 pounds. 



The soil is prepared as in the greenhouse method, a few 

 potatoes being buried at a depth of a foot to gauge the 

 degree of heat attained, or a soil thermometer may be 



