570 Journal of Agriculture. [lo Sept., 19 io. 



" SCAB " AND EEL-WORM IN POTATOES. 



Results of Experimental Plots. 



Report by E. S. Holmes, Assistant to Chief Inspector of Produce. 



The experimental plots for the purpose of testing means for the pre- 

 vention of Scab and Eel-worm in potatoes were situated in various parts 

 of the State — two in Gippsland, two in the Warrnambool district, one at 

 Lancefield, and two at Wallace, near Ballarat. It will thus be seen that 

 the experiments extended over a very wide range of potato-growing country. 



Of these seven plots, four were satisfactorily carried out, and gave 

 reliable returns. I refer to those of Mr. Crowe, at Koroit, Mr. Summers, 

 at Lancefield, and Mr. Shearer and Mr. Downey, at Wallace. The plot 

 at Mr. Gummisch's farm at Bunyip, although well looked after, was 

 finally destroyed by "Sore-eye" disease, and no reliable results could 

 be obtained, whilst the plot at Illowa gave no results, as it was neglected, 

 and the cows obtained access to it. The plot on Mr. Morton's farm at 

 Drouin became more or less overgrown with bracken fern, and being in 

 hard ground, the results were poor. 



Classifying the five plots from which results were obtained, three (those 

 of Messrs. Downey, Shearer, and Summers) supply returns for Scab 

 treatment, whilst those of Messrs. Crowe and Morton give data for the 

 treatment of Eel- worm. The scheme of treatment was the same for both. 



The plots in every case were situated on portions of land which were 

 known to be more or less subject to either one or the other condition, 

 and as the experiments were thus carried out under exacting conditions, the 

 benefits derived from any line of treatment are worthy of full consideration. 

 Taking the plots for Scab first, we find that whereas some so-called reme- 

 dies did not fully justify their u.se, others again were very satisfactory. 

 The latter was the case with the formalin treatment of Scab. 



Experimental Plots for Scab Treatment. 



Formalin Treatment. — Formalin, as is well known, is a strong fungi- 

 cide, being often used in place of bluestone for the pickling of wheat to 

 prevent smut, and it was thought that probably its use would result in the 

 restriction of a disease like Scab,* which in one form is caused 

 by a minute fungus living on the substance of the potato. For the pur- 

 pose of testing this idea, two plots of six rows each were taken side by 

 side. In one plot, scabby seed was sown without any treatment, while in 

 the next the seed was treated before sowing with a solution of formalin of 

 a strength of i lb. to 30 galls, of water. The seed was soaked whole 

 in the .solution for two hours, and was then dried before cutting. 



As shown by the following table, No. i plot at Mr. Downey's, which 

 was sown with untreated scabby New Zealand Pink-eye seed, returned 

 only 45.7 per cent, of clean potatoes, while in plot 2, which was sown 

 with similar seed which had been treated with formalin, yielded 74 per 

 cent, of clean tubers, or a gain of 28.3 per cent., equal to 5^ cwt. in 

 each ton of produce. Further, the rejected sample from the untreated 

 seed was badly scabbed, whilst that from the treated seed was compara- 

 tively lightly scabbed, and many of the potatoes could have been included 

 in a marketable sample; this also applies to Mr. Shearer's plot. 



* Whilst the Potato Scab known to science is caused by the fungus Oospora scabies, otlier agencies, 

 even mechanical injuries, may produce a " scabby " appearance of the tubers. In this report the term 

 " scab " has been used in its widest sense.— Editor. 



