NARCISSUS EELWORM. 



71 



Chemical Sterilization Experiments (Series II.). 



Although the experiments of previous workers with chemical 

 sterilization of the soil for the root-knot eelworm (Heierodera radicicola) 

 had proved ineffectual, it was thought desirable to conduct this series 

 of experiments to test the possibility of finding some chemical which 

 would prove successful in controlling the Narcissus eelworm (Tylenchus 

 devastatrix) . The chemicals employed were gas-lime, calcium carbide, 

 naphthalene, worm-killer, carbon-bisulphide, toluol, formaldehyde, 

 ammonia, and a proprietary preparation, and were applied at the 

 following rates : — 



Plots K and P 1 : Gas lime at the rate of 8 lb. to the square yard. 



,, L and Q 1 : Calcium carbide „ i£ 

 ,, M and R 1 : Naphthaline (flaked) ,, 3 oz. 



,, N and S 1 : Worm killer ,, 2 



11 O and T 1 : Control 



„ P and K 1 : Carbon-bisulphide 4 

 „ Q and L l : Toluol „ „ 4 



RandM 1 : Formaldehyde 40 per cent. One part in 20 parts of water at the 



rate of 1 gallon to the square foot. 

 S and N 1 : Ammonia 30 per cent. At the rate of twelve ounces to the 



square yard. 



T and O 1 : Proprietary preparation. According to directions. 



The carbon-bisulphide, toluol, and ammonia were applied by means 

 of the Vermerol injector, the depth of injection being one foot, and 

 twelve holes made to the square yard. The formaldehyde solution 

 was applied by means of a watering-can. The gas-lime, naphthalene, 

 calcium carbide, and worm-killer were distributed by hand and forked 

 into the top twelve inches of soil. The plots were treated throughout 

 the same day and six weeks previous to planting the bulbs. 



The beds were examined in the Spring, and, as in the case of the 

 bulbs in the manured plants, the growth was clean and healthy. The 

 bulbs were lifted in the Autumn, and in every instance the treated 

 plots produced diseased bulbs, and no difference was apparent in the 

 extent of the disease between the bulbs from the treated plots and 

 those from the control. 



The results of these experiments point to the conclusion that the 

 treatment used could not be depended upon to free the soil from 

 eelworm. 



Susceptible Crop Experiments (Series III.). 



This series of experiments was included, as it is of importance to 

 give such a rotation as will not place a crop liable to be attacked in 

 immediate succession to an affected crop of Narcissi ; it was therefore 

 necessary to see if crops liable to attack by the Narcissus eelworm 

 could be sown with safety on land which had carried diseased bulbs. 



Tylenchus devastatrix has been recorded on rye, winter and spring 

 oats, clover, lucerne, peas, broad beans, rye-grass, onions, wheat, 

 chives, buckwheat, and potatos. 



The plots for these experiments were sown or planted with the 



