Summer Spraying

Hawke's Bay Herald-Tribune, Volume 81, Issue 14, 9 October 1937, Page 16

Summer Spraying

Mr. N. ■ J.x Adamson, Government

POINTS TO NOTE More Than Ordinary Caution Necessary ADVICE TO ORCHARDISTS

(By

Orchard Instructor). The spraying stiason may be nominally divided into two parts: first, the pre-blossom period when the most important foundation sprays for the control of fungi are applied; and secondfy, the summer period, beginning at petal-fall, whcn both fungi and insect pests have to be. dealt with and combination sprays are usually applied. The first period is covered, as pears are in full bloom and apples are just approaching the maximum blossoming, so that consideration should now be given to a plan of action for the summer period. Applications of fungicides for the control of black spot on pears, black spot and powdeTy mildew on apples, must be continued throughout the summer, and such sprays must necessarily be much milder to avoid fruit and foliage injury. Active insect pests, the principal one being codlin moth, must also be dealt with by the tise of suitoble insecticides. Combination sprays may be used, but in combining sprays, care is required to void any mixture which may . eause injury to tho trees to bo protected. Trees v.ary greatly in their tolerance to certain sprays and modifications of standard recommendations are frequently necessary, according to variety and condition of trees. Applp trees, in a state of weaknoss brought about ' by poor drainage, insuf-. ficient pruning and carrying an excosslvely heavy crop, will readily scorch with the injudicious use of lime sulphur during the summer, especially if conditions are very - dry. Such trees will become progressively intolerant to this spray as the season advances. Heavy Blossoming. ' Following the complete destrutcioc af last season 's crop, .blossoming will be exceedingly heaVy, notwithstanding the fairly heavy pruning carried put. Fruit setting may be in excess of nOrmal, and with moderately dry conditions prevailing at the moment and a posibility of such conditions continuing, nlore thah ordinary caution should be exercised in the spraying programme adopted for this season. Many trees in certain localities, where drainage proved inade-: qUate, are showing lack of vigour through injury to roots caused by the excessive wet during the autumn and winter of last year and will be Teadily injured by sprays of a causti'c nature. Normally the most suitable combination npray for apples at petal fall is as follows : — Lime siilphur, .1-150 ; Colloidal sulphur or equivalent, 21bs.100 gallons ; arsenate of lead, l^lbs.-lOO gallons j hydrated, lime, 31bs .-100 .gallons. ,For the secOnd summer application lime' sulphur should be reducpd in. strengthi to 1-180., . Lime sulphur should be omitted when spraying tehder varieties, including Cox's Grange and Dunns, which will russett readily .and ' will show foliage injury under normal circumstances. Similar action should be taken. whero trees ' are at all weak. The use of hydrate lime is necessary when lime sulphur' and arsenate of lead are used in combination to reduce the amount of free arsenic which may be liberated. As a further precaution in combining these materials both should be well broken. down before bringing together. The method of mixing is to almost fill the spray vat and add the lime sulphur. Mix the arsenate of lead and hydrate lime dry, and add water to make these two ingredienta into a milk and, after diluting in at least four gallons of water, for a mix of one hundre.d gallons, slowly add, to. the diluted "lime sulphur, while the agitator in the vat is running. Colloidal sulphur may be added next. Should nicotine sulphur be required at any time for the purpose of combatting attacks of apple leaf hopper it should be added immediately before spraying begins Treatmint of Pears. The spraying of pears during the summer period may be the same as for ;ipples -in the main. Lime aulphur siiould not be used on Josephines, however, but this variety, which is tender foliaged, should be sprayed as for Cox's Grange apples. Under most conditions it is necessary to spray varieties such as Winter Neiis, Wjlliams, Louie Bon de Jersey, Packhams and Doyenne du Comice, with Bordeaux 3-4-50, Normally these varieties may be sprayed as for apples or a colloidal copper preparation may be used instead. Winter Coles are not so tolerant to copper sprays, as they roughen the surface of the fruit so that for this variety sulphur syrays are prefered as fungicides in the summer, Good cultivatjon keeps the trees vigorous, a condition which is very necessary to secure the most ' effective spraying results without injury to tree or fruit, • Spraying Of Peaches. Although little trouble should be experiehced through brown rot if dry conditions prevail, it is necessary to apply sulphur sprays to peaches, nectarines and European plums for the control of leaf rust. The most effective spray is lime sulphur, 1-200, with colloidal sulphur, 21bs. to 100 gallons > after petal fall and at intervals. Spray-

ing should not be done if rain is threatening and quick drying is not guaranteed. If spraying of peaches is carried out following the spraying of apples and pears, cleansing of the pump, pipe lines and hose is necessary to rembre all traces of arsenate to which peaches are most intolerant.