418 STATE BOARD OF AGRICULTURE. 



NAPHTHALINE TREATMENT. 



As naphthaline was known to be more or less of a repellant to certain 

 insects, it was suggested that it be given a trial. The original intention 

 was to mix flake naplilhaline with the soil. As it was not possible to 

 obtain naphthaline in the flake form at the time it was desired to start the 

 experiment, it was necessary to use it in the form of small balls, -com- 

 monly called ''moth balls." " May 15, 1913, plot lY was treated as fol- 

 lows:' — Holes were made in the soil at intervals of eight inches to one 

 foot, and varying from six to twelve inches in depth. One or two naphtha- 

 line balls were dropped into each hole and the mouths of the holes then 

 closed with soil packed into them. About one and one-half pounds of 

 moth balls were used on the plot. May 31, 1913, the writer planted toma- 

 to and cucumber seeds in the naphthaline treated soil. June 16, 1913, 

 some of the plants were dug and examined and found free from root- 

 knots. June 30, 1913, the author examined tomato and cucumber plants 

 from plot IV and found knots on their roots. This proved that the 

 naphthaline treatment applied would not control the root-knot nematode. 



AMMONIA TREATMENT. 



May 15, 1913, plot V was prepared for treatment as in plot IV, by mak- 

 ing holes in the soil with a brass dibble. A small amount of 28% 

 ammonia was poured into each hole, and then the holes were quickly 

 plugged with soil. The ammonia gas soon penetrated the soil and gave 

 the air in the vicinity of the plot a very strong odor. About three pounds 

 of ammonia were used on this seven by ten foot plot. May 31, 1913, let- 

 tuce, tomato, and cucumber seeds were planted in the treated soil. June 

 16, 1913, some of the plants were dug up and knots found on their roots. 

 This would seem to show that such an ammonia treatment had no effect 

 on the nematodes in the treated soil. Later on in the season this plot 

 was used for starting an experiment with ginseng roots apparently 

 resistant to nematodes. 



"BLACK LEAF 40" TREATMENT. 



It had been intended to make this and the following treatment at the 

 same time the others were made, but they were delayed because we could 

 not get the "Black Leaf 40" and the tobacco dust at that time. "Black 

 Leaf 40," a commercial nicotine product made by the Kentucky Tobacco 

 Products Company, has proven quite efficient as an insecticide for cer- 

 tain types of insects. As a result of its success as an insecticide, it was 

 suggested for nematodes. Directions on the sealed can recommended the 

 use of a one-half pound can of this concentrated nicotine product to 

 thirty-four gallons of water, for all ordinary insects. This dilution was 

 supposed to give not less than seven hundredths of one per cent nicotine. 

 May 31, 1913, plot VI was treated with "Black Leaf 40" solution made 

 up according to directions, and applied to the soil at the rate of one gal- 

 lon per square foot. June 2, 1913, the writer planted lettuce, tomato and 

 cucumber seeds in the treated soil. June 30, 1913, he dug up and examin- 

 ed lettuce and tomato plants from plot VI and found knots on their 

 roots, thus showing that such a dilution of "Black Leaf 40" would not 

 control root-knot nematodes. 



