26 
“THE ONION EEL-WORM. 
Experiments for the Eradica- 
tion of—With a Short Des- 
. Cription of its Life History 
and. Habits. 
[By W. Laidlow, B.Sc., Micro- Biologist; 
and ©, A. Price, Microscopist, in 
the ‘ Vic. Journal of Agriculture.’ | 
It is only within recent years that 
special attention has bean directed to the 
aystematic study of the Nematoda or 
thread worms parasitic on plants, as 
distinguished from those 
though ° 
affecting 
experiments 
by the 
the 
of eel-worms affecting the 
animals, various 
were made many years 
Agriculture for 
ago 
Department of 
eradication 
onion crops in the Drysdale district. 
‘In the year 1890, Dr. N. A. Cobb, in 
the ‘ Agricultural Gazette of New South 
Wales,’ called attention to the fact that 
an eel-worm, known to science as Tylen- 
chus devastatrix, was believed to exist in 
Australia This was confirmed by an 
article from the pen of Mr. A. N. Pear- 
non, who at that time was Agricultural 
Chemist of Victoria. 
“At the instance of the late Mr. Levien, 
M.L.A., a prominent onion-grower, Mr. 
Pearson visited the Drysdale district for 
the purpose of ascertaining the cause of a 
disease aflecting the onions. He dis- 
covered in the diseased onions a minute 
eel-worm. He says :— 
"The ground at present is in a deplorable 
state. It is not surprising that this should 
be'so. In almostall cases where crops are 
grown year after year on the same land, 
without rest or change, such a condition 
of things arises, but besides this continu- 
ous onion growing the ground is not cleared 
of the diseased onions, which are allowed 
to remain ada the eggs or spores to 
the next season. 
For many years previous to this date, 
this land had been continuously cropped 
with onions, owing to its suitability for 
their culture. 
the conclusion that the only remedy for 
the state of. ihings then existing was an 
entire change in the. _system. of agricul. 
ture, the abolition for a time of the 
Mr. Pearaon arrived at then, numerous experiments 
THE AUSTRALIAN GARDENER. 
onion crop from the district and the 
establishment of suitable rotations. He 
experimented with a number of chemi- 
cals, including chloride of lime, gas lime, 
dilute solutions of mercuric chloride and 
dilute arsenical solutions. He also 
burned straw and brushwood on the 
surface of the soil, without any or only 
slightly beneficial effects. 
Dr, Cobb applied to Mr. Pearson for 
specimens of the diseased onions, which 
were forwarded and on which he con- 
tributed a report to the ‘ Agricultural 
Gazette’ in 1891. 
cription of the anatomy of the eel-worm 
(which he recognised to be Tylenchus 
After a minute des- 
devastatrix), and the various agencies by 
‘which it is spread, he suggested the 
following remedies :— 
1. To destroy all affected plants. 
2. To remove all weeds that might afford 
the worms a subsistence. 
8. Removal of the first three inches of 
the surface soil. 
4. Deep and thorough ploughing, which 
turns the soil exactly bottom side up. 
5. The promotion of a rapid growth of 
plants cultivated, 
6. Sowing the infested land thickly with 
rye, and reaping it while young. 
7. Injection of carbon bisulphide into 
the soil, the injections to: be shallow and 
numerous, 
8. A good system of drainage. 
In the year 1891, various chemicals 
were tried by Mr. D. McAlpine, Vege- 
table Pathologist, for Ait eradication of 
the onion eel-worm, The following 
chemicals were used during the experi- 
ments carried out at that time :— 
1, A mixture of sulphate of potash and 
sulphate of ammonia. 
2. A dressing of lime. 
3, Spraying the plants with diluted. 
phenyle. — 
4. Spraying with dilute corrosive sub- 
limate. 
5, Dilute corrosive sublimate applied to 
the soil in the badly affected parts. 
6 Sulphate of iron forked in between 
the rows of the onions, 
These chemicals, it is stated, produced 
no effect, the disease being as bad on the 
treated as on the untreated plots. Since 
for the 
eradication of this pest have been tried 
by other investigators, principally on 
their own initiative. Among these, 
special attention must be made of Mr. R_ 
April, 1910 
J. Eletcher, of North Geelong, 
work extended over a period of four 
years, 
whose 
and ineluded not only the effect of 
chemical substances and manures on the 
affected land, but also a study of tie life 
history of the eel-worm. By this observer 
over 300 plots were treated, scattered 
over nine different farms in paddocks 
known to be diseased, and included 
within an area of 30 square miles, thus 
getting a variety of soils, drainage, and 
other conditions. 
The chemicals used were the following:- 
Sulphurous acid, chloride of lime, arsenic 
and soda, potassium cyanide, corrosive 
sublimate, spent oxide from gas works, 
common salt, ground quicklime, freshy 
slaked lime, saccharated, snlution of lime, 
flowers of sulpur, precipitated sulphnr, 
and naphthaline. Ont of this compre- 
hensive list of chemicles, he found that 
suphurous acid and ammonia were the 
only two that gave results worth further 
consideration, As the sulphurons acid 
was only tried on two farms, the results 
obtained were not considered conclusive. 
Some experiments with the gas were 
carried out by us in the laboratory, but 
the soil as rendered so acid that onion 
seed failed to germinate. No good results 
wore obtained by enriching the soil by 
manusal treatment, or burning bushwood 
or straw on the surface. Mr. Fletcher 
summarizes as follows: — 
No good is obtained by chemicle insecti- 
cides, fertilizers, change of seed or burning, 
and little reliance can be placed on trans- 
planting. Good barley can be grown on 
diseased land and can he followed by one, 
sometimes two, good crops of onions ; then 
barley must be sowu again. Soil fertility 
has little to do with the presence of eel- 
worms, 
(To be Continued.) 
M. L. Tomlinson, 
(LATE J. G. ORAM), — 
Manufacturing Jeweller, 
Watchmaker, 
Diamond Setter & Engraver. 
Repairs to Watches, Clocks, and Jewellery 
of every description accurately, artistically: 
and promptly executed at moderate pricos. 
27 Grenfell St., Adelaide 
