AN ENEMY TO FARMERS.

Waikato Times, Volume VI, Issue 312, 14 May 1874, Page 3

AN ENEMY TO FARMERS.

(Wanganui Chronicle). Our potatos tire in danger. The enemy is still afar off, but he is committing great havoc where he is located, and is gradually extending and advancing his lino of attack. It is therefore necessary for our iariners to be prepared beforehand for his reception. This enemy is the Colorado potato beetle, or, to use the scientific name, Dorgphora decempuncfata, and is altogether a most objectionable character. Heat and cold, rain and dryness, are equally indifferent to him, and although he profers potatos, will eat. eabbagei if the savoury tuber is not to be obtained. The home of tl.is beetle is in the Rocky Mountains, where it feeds upon a species of wild potato, and flourished thereon until the white man began to cultivate the land at the base of the mountains, when it at once attacked the edible kind, and committed immense ravages in the district. Since then, it Las rapidly extended its devastations, and whole armies of these beetles have marched eastn ard, year by year gaining new territory. The first batch of infant larvae appears towards the end of Hay, or, if the weather be mild, of April. In fact, scarcely has the potato plant shown above the ground before the insect awakes itself to life. The female loses no time in depositing from 700 to 1200 eggs, in clusters of 12 or 13, on the outside of a leaf. Within five or six days, according to the weather, the larvee escape from the egg, and begin their work of devastation, which which goes on for some 17 days, when the little creatures retire below the soil in order to undergo the pupil condition. After a delay of 10 or 14 days, the perfect insect comes into being, and the business of egg laying commences anew. In this way, according to recent observations, three broods follow each other; the last, as just stated, wintering below the surface of the ground. No description can do justice to the marvellous voracity of this insect, especially in its larval state. When once a field of potatos has been attacked, all hope of a harvest may be given up ; in a few days it is an arid waste, a mere mass of dried up-stalks. The only effectual means of destroying the beetle yet discovered is dusting the plants with Paris green, a compound of arsenic and oxide of copper ; but the remedy is almost as bad as the disease, since it is dangerous to the distributor, and calculated to permanently injure the soil. The Daryphora is therefore not an enemy to be despised ; nor must the furmers of New Zealand overlook the fact that if it once gams a footing in England, it will not be very long before it reaches New Zealand, where it would probably find crops prepared for its ravages from want of care in maintaining stamina in the stocks. Practically, nothing has been done here for this end ; and the effects would have been felt long ago had it not been for the constant breaking up of waste ground, which, in another way, has seived the same purpose as a change of seed would have done. Strenuous efforts have been made at Home to invigorate the plant by raising stocks from seed, instead of the usual cuttings, and large sums of money have been spent in these experiments, which have proved successful. It has thus been shown that the true method of preventing disease in tho potato is to raise new kinds from the seeds contained in the plum. This, although on the face of it simple enough, is by no means an easy task, but requires much care and patience, as jnany failures must be expected . But once accomplished, it is thoroughly efficacious, and therefore worth all the pains bestowed upon it.