PLANT DISEASES.

New Zealand Herald, Volume LXVI, Issue 20425, 29 November 1929, Page 7

PLANT DISEASES.

LARGE ANNUAL LOSSES.

PREVENTIVE METHODS

A writer in tlio New Zealand Journal of Scienco and Technology, dealing with ■ the subject of cash losses due to plant diseases in tho Dominion estimates the annual value at £2,221,500. In this summary he includes only oats, peas, potatoes, turnips and marigolds. Fruit, vegetables and various M other crops are not mentioned, so that the total must be infinitely greater ind as ' the writer says "no account is taken of reduction in yield due to attacks of clisease net sufficiently severe to cause total loss.'' Nor is account taken of losses due to reduction in carrying capacity, milk, meat and wool yield caused by failure or partial failure of crops due to disease. If all these were added together it is probable that tha total loss would be nearer £4,C00,00G than £2,221,500. It is pertinent to ask if this great loss can be prevented and if so, how? The answer is satisfactory enough in a way for much of this immense sum could undoubtedly be saved by more scientific methods of farming and gains made besides.

The average farmer does not wish to wait until new scientific methods . are evolved nor need he. It can.be taken as. a general fact that much of the loss, caused by plant diseases is due to the fact that the soil on \vhich - the plants are growing is not properly supplied with the right kind of plant food. There.'is a deficiency so mew; here and scientists are finding out daj* by day what these (deficiencies are, but in the lack'of definite knowledge the fanner can very largely insure himself against diseases in his crops by first of all seeing that his soil is well drained, where drainage is necessary; that it is well cultivated; and thirdly, that it is well supplied with all the elements needed for the full development of plant life. A fourth factor is ijecessary and that is that all seeds of farm crops should be so far as is possible free from the spores of plant disease and of as pure and vigorous a strain as can be procured. Dnder the present conditions most farmers know to supply the main elements, of fertility through well-known manures and in most cases they are able to obtain healthy virile seed if they care to pay . the price. Looking at this matter in a. broad light does it not show what immense scope there is for science in farming when it opens up the way not only to prevention ' of diseases, but also to enormous, increase in crops due to improved methods of culture, the use of suitable fertilisers plus" a steady, improvement in the quality of farm seeds due to the careful selection, hybridation and the introduction of new varieties.