Fruit Blights and Diseases of Fruit Trees in New Zealand.

Lake Wakatip Mail, Issue 1524, 26 March 1886, Page 5

Fruit Blights and Diseases of Fruit Trees in New Zealand.

Above is the heading of an interim Parliamentary

report by Professor Kirk, who, in compliance with i instructions, had been making inquiries concerning j various diseases of fruit trees in this colony. As j Prof. Kirk points out, the report is necessarily in- , complete, owing to his researches having been rei stricted to the winter months; and it was con- ' sequeutiy impossible to ascertain the life-history iof many fruit pests. He further states that, alJ though the ravages of insect and fungoid pests have I assumed formidable dimensions in several districts, i this trouble has, in nearly every instance, been the | result of ignorance of the nature of the evil itself, i and of the best remedies to lie applied in each case. I This high authority on such matters remarks : " Even in the present imperfect state of our know- : ledge the enendes of the fruit-grower may be kept I within moderate bounds, and, in most instances, completely eradicated ; so that there is nothing in ; this direction to prevent fruit-cultivation frcm being i placed in a satisfactory position throughout the colony." j As to the extent of injury which had been effected, | the Professor states that it was not easy to form | an approximate idea at the present stage of his enquiries, although he considers that, in most cases, loss could have been prevented by a little timely care. Professor Kirk also nrge« that the importaj tion should be strictly prohibited of diseased or ; Affected fruits, and that imported fruit trees should , be inspected on being landed. He asserts that "it l forms uo real objection to prohibition that an insect [ or a fungus may already be established here, since a change of climate ofteu conduces to increased vigour, arid the new comer iucreases with greater rapidity than its established congeuor." Speaking of prevention and remedies, the Professor states that the climate of New Zealand is exceptionally favorable to the rapid increase and vigorous growth of insect* and plants introduced from temperate countries—especially those from Europe, which flourish with a vigour rarely exhibited in their native country. In former years fruit cultivation was carried on under e isier conditions. As few insects had been introduced, and indigenous kinds had not discovered the more enticing food supply afforded by introduced fruit trees. Now, however, the intending fruit-grower must consider this risk before planting, for. unless he determines beforehand that his trees shall be kept dean at any cost, his anticipation of profit will he disappointed, and hia orchards will be a source of in lection for the whole country side. Unless grown in pyramidal form trees should be kept open in the centre, as insects increase more rapidly in proportion as they rind shelter and protection. Primings and thinnings from affected trees should be promptly destroyed, to prevent the establishment of insecrs and fungi in new locdities. Moss and lichen should not he allowed to grow on tr«-es, and c;rass and weeds should b>r eradicated from about the roots. The result* of tin: application ot insecticides should be carefully vvalclud, and the treatment promptly repeated, if found !:ec(S«.'.ry. In the majority of casis insects may lx? extirpated with but little trouble on their first appearance ; but if allowed to increase until the I entire orchard is afi°cti'd their extirpation will involve a iarj.e expenditure ot time ami labour. In his general remarks upon the remedies applicable to the chief classes of noxious insects. Plot, h'rk makes some interesting comments under the K-siH'ctive heads which can only be In ii tiy extracted lieie. It is stated, under the following head : -

*\Vc nit. —No insects are more easily destroyed tli in the :i|>[i!>' scale ami it-s ellioh with horny shields : ill? castor-oil mixture, recommended under spp e-sc.tle, ha 3 never failed when proja-r!y applied. It Li inexpensive, easily applied, and lrirmli 83 to vegetation. It should be used during the wint-r <>r early spring months, before the •uinniein-etii'iit of growth, and should he applied with ali :ht hand. In excessive (piallties it tends to retard j/rowtn, but does nut permanent harm. In all r»-.*|>t<ts I prefer cantor-oil to kerosene :>s an inscutL-iJe ; it is equally destructive to insect-life, and «it<es not iujuie the plant, as is often the case with kerosene. For those who prefer kerosene emulsions, 1 would recommend lib. soft sop.p, dissolved in a gallon of boiling witei, with the addition of a pint of kerosene. Insecticides consisting chiefly of oils should always l«c applied lightly, as for the most put they cause injury to the superficial tissue of the plant."

•' White Sruu (hmjn).- Syringing, or spraying with x guV.en engme, with :i solution of caustic n<,ia»li, loz. to ;t gallon of writer, is most effective ; »r the raptor-oil mixture will be fouti'l excellent. Knmls'ons '.f turpentine and milk, or soapsuds applied with the syringe, would be of high value. "Concentrated lye" is strtng'y recommended by \ni*ri-jni cultivators as a remedy for scale. Its cost here would be fid. or 7d. per lb. wholesale. It is applied with a syringe or garden-engine, in the proportion of lib of lye to a gallon of water; stroller solution* are injurious to the tree. It is sa'd to contain about S per cent, of cai'stic potash, the rema.nder consisting of carbonate of soda, with a (-mill percentage of caustic soda. lam satisfied that «;i|U.ill) good results may he obtained with • instil potash alone, in the proportion uf l l oz. to a gallon of water, at a cost of Id. or IJd. at most." " f y mdvi"ici rm and other uninll CntfrjnUam. — freely with weak solutions of caustic not.ihh. Pii«ting the trees with i'aris-green has be<n found beneficial, but greater care should be tike.) in applying this mnedy. Should i* fall on a '•ut or wound on the hand »r elsewhere, the results might be of an unpleasant character. " l.enf-iij'hi*.— Syringe freely with soapsuds or even with cold water. In most casts this will be found sulFicient to dislodge the insect, but with son e kinds it may be necessary to use a weak solution of caustic potash. The aphides infestiti" fruit-trees in New Z-alnnd appear to be identical with Kuropcan species."'

" Slutj-l'-*ch.— White hellebore powder has been found effective, but I believe the caustic-potash solution would Ik- e\en more beneficial." " Leaf-fnniji. —l believe solutions of jiernunjanate of potash would lie found effctive with nearly all fungoid pests attacking the leaves. I hone to carry out a series of experiments in this direction during the coming spring. Dusting the leaves a fleeted with fun.'i with sublimed sulphur or with (Joodhue's mixture will be found productive of good results." " Root-fiin<ju*.— ln addition to tar-water, I have to suggest the following experiments with a view of eradicating this past : (I) Top-dressing of lime, at the rate of twelve bushels to the aire, to be dim in and well mixed with soil. ('I) The same, with the addition of lib. of sulphur to each bushel of lime. i 3) Top-dressinc of soot, at the rate of ten bushels to the acre. (4> Top-dressing of salt, at the rate of 3c»vt. to the acre, applied in the autumn.''