APHIS AND DIAMONDBACK MOTH

New Zealand Times, Volume XXXIII, Issue 7867, 1 August 1911, Page 2

APHIS AND DIAMONDBACK MOTH

THE EFFECTS OF SPRAYING. Tho long spoil of dry weather had no doubt tho effect of intensifying tho attack of tho above parasites, and the swedo crop of tho xiast season at the Moumahaki Experimental Earm suffered to some extent in consequence (writes Air Primrose McConnell in. tho "Agricultural Journal/'') Under tho directions of tho biologist, tho following sprays were tested on a paddock of nine acres, ono half of the paddock being sprayed and the other left as a check. In taking- tho cost per aero into consideration it must bo remembered that if a water supply is not within | easy distance tho cost will bo consider* ably increased. In tho present case a good supply of water was available in tho affected paddock. Tho speed .at which a sprayer travels will also lessen the cost. If tho horse walks at a quick pace tbo cost will be comparatively small, os only a comparatively ©mall quantity of tho spray will bo used, and tho work will bo more or less effective in proportion. I find that graying only onco over, if slowly and carefully done, required about 80 gallons of liquid Per acre.

The following gives tho names and cost of labour and material of the different sprays used: Sunlight soap, 7s 6d per aero*; ilcDougall'c insoctcide, 13s per aero; JNikoteen, d;l 2s 6d per aero; kerosene” emulsion, Hs per accro. Whoa tho work of spraying was Undertaken tho attack was well developed, both aphis and moth being present in enormous numbers. Tho spraying machine uswi (a Strawsoniser) was attached to an ordinary farm cart, the pump requiring two men to maintain the necessary ' pressure. From-the first it was very apparent that complete success could not be expected, as it was found impossible to lower the nozzles sufficiently so that the spray would reach tho under-surface of tho loaves. To make the latter possible, when spraying from an ordinary cart tho turnip rows would require to’ be of a uniform width of SOin, so that the wheels would travel in the centre of a row, the nozzles also occupying a similar position in each row If the rows are irregular, or the turnips sown broadcast,'“top” spraying only is possible, as the turnips continually obstruct the nozzles and prevent them from being lowered sufficiently. Two days after spraying was carried out I examined the turnip foliage carefully and found that, with the exception of the Sunlight soap all-the sprays had killed of dispersed the parasites where the two had come in contact, but tho lower surface of the leaves, without exception, were still covered with live insects. The sprayings would probably have shown a bettor result had they been carried out at an earlier stage. I am of opinion that tho spraying of swedes will only be successful when done as a preventive. . This would probably require two sprayings, the cost of which would bo very considerable—probably too much to be practical. As far as can be seen, tho spraying in this instance has had no final result. A great percentage of the leaves of both the sprayed and unsprayed swedes has dropped off, and in both cases now and clean foliage is appearing. Taking tho drought into consideration, the bulbs have grown well in spite of the parasites, and’ they are perfectly sound, and quite an average crop-dn fact, the only passable crop of swedes I have seen this season. Tho success of the crop in spite of all the difficulties it had to encounter is no doubt duo to tho effects of green manuring and thorough cultivation. I consider that if.the soil is thoroughly cultivated and judiciously manured, so as to make the plant as vigorous as possible, an ordinary attack of aphis in an average season need not ho much dreaded, except the attack occurs when the plants aye young. Certainly the crop in question has come through the ordeal much better than I anticipated.

is preferable to that which is less good, but fairly good fruit is vastly better than none at all. Never bo afraid to avail yourself of all the light which experience has shed upon tho whole subject of apple culture. Thoro is no danger of your knowing too uuch. A little knowledge is sometimes a dangerous thing and may be worso than none.

Never forget that good apples are grown under the eye of eternal vigilance and tho hand of untiring industry.