lo March, 1910.] 



Tlic Onion Eel-ivorni. 



16: 



further consideration. As the sulphurous acid was only tried on two 

 farms, the results obtained were not considered conclusive. Some experi- 

 ments with this gas were carried out by us in the laboratory, but the soil 

 ■was rendered so acid that onion seed failed to germinate. No good 

 results were obtained by enriching the soil by manurial treatment, or 

 burning brushwood or straw on the surface. jNIt. Fletcher summarizes 

 as follows :- - 



No good is obtained by chemical insecticides, fertilizers, change of seed or 

 burning, and little relinnce can be placed on transplantinj;. Good barley can be 

 grown on diseased land and can be followed by one, sometimes two, good crops 

 of onions; then barley must be sown again. Soil fertility has little to 'lo with 

 tlie ])resence of eel-worms. 



During the season 1909, further experiments with some of the more 

 recent chemical substances were again undertaken by the Department, the 

 land being kindly placed at our disposal by Cr. R. Willey, of East 

 Bella.rine, who is an old resident, and a close and enthusiastic observer of 

 the eel-worm and its habits. 



The soil in this dLstrict formg an almost ideal nidus foi the develop- 

 ment and spread of nematodes, being volcanic, rich in humus, and capable 

 of retaining a large amount of moisture. The followmg recent analyses 

 will give some idea of its richness in plant food : — 



Parts per 100, odo. 

 Nitrogen ... ... ... ... ... 284 



Phosphoric acid ... ... ... ... 102 



Potash ... ... .. ... ... ... Ux] 



Lim.e ... ... ... ... ... ...■ i,jou 



Chlorine ... ... ... ... ... ^ 



The large quantity of lime present in this soil is mainly due to the 

 •use of sea shells as a means of altering its mechanical condition, it being 

 of a veiy sticky and tenacious character, when moist. 



A number of plots were set apart for the experiments, each measuring 

 one-fortieth of an acre. The land, having been recently ploughed and 

 harrowed, was in a fine condition ; but, owing to the wetness of the season, 

 together with the sticky nature of the soil, and the absence of drainage 

 excepting that of the natural fall of the ground, it was somewhat difficult 

 to apply the chemicals to the soil, especially those in solution. 



The following is a list of the chemical solutions and powdered sub- 

 stances u.sed in the experiments, together with their cost per acre : — 

 Plot I. — 2g lbs. of Potassium Cyanide at lod. ])er lb. ... ^^"4 3 4 



Plot 2. — 3 pints of Cyllin at 7s. per gallon ... ... 5 5 o 



Plot 3. — I lb. Potassium Cyanide at lod. per lb. ... ... 150 



Plot 4. — 25 lbs. of Apterite at los. per 100 lbs. 



Plot s. — 3 lbs. of Vaporite 



Plot 6. — 15 tins of Pestox at is. 6d. per tin 



Expense prohibitive. 

 4 10 o 



Method of Application. 



Plot 1. Plot t. Plot 3. Plot 4. I Plot 5. Plot 6. 



l-40th ofanacre. I l-40thofanaL-re 1 40th of an acre. 1-SOth of an acre. 12 square .yards. l-40th of an acre. 



Watered three 

 times with 100 

 gallons of Potas- 

 sium Cvanide, 

 •08 % solution, 

 at intervals of 

 three weeks. 



Watered three Watered four Treated with Treated with 

 time.s withjtinies with 100; 83 lbs. of powdered lib. of Vaporite 

 Cyllin solution, gallons of •02;j % Apterite, forked in the same 

 1 pint to 100 solution of into the soil to a , manner as Plot 

 yallons, at inter- Potassium Cya-| depth of 4 inches, [ 4. 

 yals of three nide, at intervals on three different' 

 weeks. of two weeks. occasions, at inter- 



vals of two weeks. 



Watered three 

 times with 100 

 gallons of water 

 containing l:[lbs. 

 of Pestox, at 

 intervals of two 

 weeks. 



During the time the plots were under treatment, the almost continuous rainfall tended to facilitate 

 he solution of the powd?red substances, and the absorption of the chemical solutions. 



