NATURE'S ELIXIR

Evening Post, Volume CVII, Issue 104, 3 May 1924, Page 16

NATURE'S ELIXIR

PLANT DISEASES CONTROL.

I The claim of Mr. Hepburn, a Scottish farmer, to having discovered the root canse:'oE the chief plant diseases,: iuc'iu'dmg bunt and smut in wheat, and .the chief diseases in vegetables, will bfi more interesting when fuller details of his experiments and conclusions are available, says the Sydney "Daily Telegraph."

The statement reads like the discovery of a panacea for all the ills of the vegetable kingdom. "The secret," it is stated, "lies in the fact that rising sap is nature's, elixir, and is the sovereign remedy. ' Fungus and insect pests attain the upper hand only when its flow is .checked." • • :

.'% Such a.,.clairo. r must be accepted with. :i'esetTations.;''- The plant certainly is most vigorous and most resistant in disease when the sap is rising, but it is an eyery-ycar experience in Australia fov insect pests to gain the upper hand when- plants are in full vigor.

In referring to the report. of the discovery, ■ Dr. G. P. Darnell-Smith, bio-; logist to the Australian Department <jf Agriculture, said lie did not think too .much importance should be attached "to it. "Of course," he remarked, "we know that certain diseases are brought about or developed apparently by a check of the sap. Irish blight in potatoes, for instance, nearly, always follows a cold snap. After a few cold nights; followed by humid.conditions, we expect Irish "blight, but whether it is due to the cold snap stimulating the fungus I dp not know exactly. The same thing oc-' cuT3 with -Hue mould in tobacco. Given two or three cold nights, followed by mild; weather, and; .the fungus will ap-: pear. It is obvious that plants are most vigorous while the sap is flowing well, and they, like human beings, become less resistant when the circulation is checked. On the other, hand, we know that we perhaps get as much or more disease in glass houses as in the open, for, although the temperature is-under control, we cannot control fungus diseases under those conditions without other precautions."

• Dr. Darnell-Smith was sceptical regarding the discovery as - applied to bunt and smut.in wheat. "In the open " '■ Jl^, "wken a man has prepared his seed bed and sown the'seed he can do nothing:more."" He did not'think1 that very mttch .could be done with a field crop,,to stimulate the sap flow. In'anv case, _he added, it was not possible to criticise the ckim much until more details came to hand. '■ ■