UNITED STATES DEPARTMENT OF AGRICULTURE 
BULLETIN No. 818 
Contribution from the Bureau of Plant Industry 
WM. A. TAYLOR, Chief 
Washington, D. C. 
PROFESSIONAL PAPER 

January 5, 1920 
SOIL DISINFECTION WITH HOT WATER TO CON- 
TROL THE ROOT-KNOT NEMATODE AND PARA- 
SITIC SOIL FUNGI. 
By L. P. Byars and W. W. Gilbert, Pathologists, Office of Cotton, Truck, and. 
Forage Crop Disease Investigations. 
CONTENTS. 
Page. 
Objects of the investigations 1 
Experiment Series I 2 
Method of procedure 2 
Results 4 
Discussion of results 6 
Page. 
Experiment Series II 8 
Method of procedure 8 
Results 9 
Discussion of results 10 
Summary 13. 
OBJECTS OF THE INVESTIGATIONS. 
The experiments described in the following pages were undertaken 
to obtain more accurate data on the effectiveness of hot water as a 
means of ridding soil of the root-knot nematode (Heterodera radi- 
cicola) (Greef .) Muller) and parasitic fungi usually associated with 
damping-off and other root troubles. 
The great need of a simple, practical method for disinfecting small 
quantities of soil in which to grow healthy seedlings for home-garden 
planting has always existed, but because of the great extension of 
tomato and other club work in recent years, the need has become 
more pronounced and more apparent. Such a method would also 
be especially adapted for disinfecting soil in pots and shallow green- 
house benches. Very successful results have been obtained by one 
of the writers in killing the root-knot nematode in infested dasheen 
tubers, to be used for planting purposes, by soaking them in hot 
water, without appreciably impairing their viability. Furthermore, 
a method of soil disinfection by hot water has been used with some 
success in vegetable greenhouses in the Boston district, but no care- 
ful experiments have been carried out to determine the temperatures 
required or the quantity of water necessary to control the soil troubles 
137551°— 19 
