NORTHERN ORCHARDS

Northern Advocate, 29 December 1934, Page 11

NORTHERN ORCHARDS

report by inspector. DISEASE CONTROL. SEASONAL VAGARIES. In the course of an inspection of the principal orchards in the Whangarei district, Mr F. M. Talbot, Government officer, noticed that crops in general are light, probably attributable to seasonal conditions. While Bon Chretien pears were blossoming very heavily, several days of wet weather were experienced. As bees do not work in the wet, this no doubt would interfere with the polonisation of the blossoms. Other varieties of pears which blossomed at earlier and later periods have not fared so badly. Apple Crop.

The apple crop is much lighter than last season, also probably due to the season’s eccentricities. The ravages of the bronze beetle appear to be far worse than in previous years, and Mr Talbot says that in some cases the fruit has been completely destroyed. Living in grass and weeds around trees and in orchards, this pest is a very hard one to combat, sprays apparently having no effect. Clean cultivation is the only control measure that is recommended by the fruitinspector. Fireblight. Fireblight, Mr Talbot finds, is not so prevalent in the Whangarei district this season. As fireblight overwinters in. cankers on apple, pear and hawthorn, and as it is carried from these to blossoms or shoots by insects, it is evident that removal of the cankers would eliminate the disease. Cutting out is practised during the summer months, especially in the earlier part of the season, since this has the advantages of preventing spread of the disease to other parts of the tree and to other trees, and induces rapid callus-formation of wound gum, thus preventing the entry of silver-leaf and other wound parasites. Cankers are, as a rule, more readily detected during this period, since the dead leaves present on killed shoots indicate their position. The method found most effective has been to cut out completely all infected laterals, fruit-spurs, or small branches, the cut being made some distance below the visible point of infection. On larger branches and limbs the canker may be trimmed and sterilised in such a manner that the limb may be saved (unless it has been killed by the organism) and the wound ultimately callus over. To this end, with a sharp knife, chisel, or gouge, removed discoloured wood to a depth of at least -gin. below the surface. Trim the wound to an elliptical or fusiform shape, the long axis being parallel with branch, and thus facilitate callus-formation.

Sterilise wound by swabbing with a sponge or brush dipped in the following solution. —Mercuric chloride, 1 gramme (l-28oz. avoirdupois, approximate); hydrochloric acid, concentrated, 15 c.c. (A fluid ounce approximate); water, 1,000 c.c. .(36 fluid ounces, approximate). This may be made up in stock solution by adding 20 grammes (5-7 oz. avoirdupois, approximate) of mercuric chloride to 300 c.c. (11 fluid ounces, approximate) of commercial concentrated hydrochloric acid. To use, dilute one part of this stock solution with 60 parts of water. Keep in a glass container. After sterilisation, as soon as the wound has dried out, paint it with coal-tar. Examine the treated canker in a month or so, and if the disease appears to be spreading, then the cutting, sterilising and painting operations must be repeated.

Stone Fruits. Stone fruits in the North are having a bad time this season, the infection of brown rot being far worse than previously. Climatic conditions play a great part in the prevalence of this disease. Warm, muggy weather, with scattered showers, seems to suit the disease and aids its spread, while a diT season holds it more or less in check. The following treatment is recommended by Mr Talbot.— (1) Apply Bordeaux mixture (5-4-50) or lime sulphur 1 per cent. At bud-movement. (2) Apply lime sulphur 1 gallon to 150. At early pink. (3) Apply lime sulphur 1 gallon to 180 plus colloidal sulphur 21b per 100 gallons. When 75 per cent petals fallen. Repeat the latter one month after petal-fall, seven weeks after petalfall, five weeks prior to first picking and three to two weeks prior to first picking. As far as practicable, remove infected twigs and spurs, and portions of shoots that may be affected. Gather and destroy all infected fruits as they appear Cultivate the soil about the trees just prior to “pink” stage of fl ower-blossom. To make 4 gallons of Bordeaux mixture spray (5-4-50) use bluestone 610 z., lime Sjoz., and water 4 gallons. When colloidal sulphur is used at rate of 21b per 100 gallons of spray, Ijoz. is required to make 4 gallons spray.