THE USE OF FUNGICIDES.

New Zealand Times, Volume LVII, Issue 2549, 29 June 1895, Page 2 (Supplement)

THE USE OF FUNGICIDES.

Wo have printed this subject, but it is of so much importance to successful fruit-growing to know how and when to use remedies against fungoid pfitasitos of various kinds that wo need not apologise for again bringing up the matter "tt season. Whilo tho loaves are off tile trees and the buds are dormant is the season when many fungicides can bo most effectually used without injury to the health of the tree. The spraying mixture can bo made much stronger without danger, and the spores more certainly killed while there is no foliage to injure, but a few consecutive' dry days will bo required to produce the best effects. An English authority points out that the work done with fungicides lias been along three principal lines, viz., to find out (1) what fungicides are most efficient and in what strength should they bo used ? (2) When should they bo applied ? (6) For what diseases are they specifics ? As has been stated, Bordeaux mixture is now regarded as one of the best, not only as being the most efficient, but because it does not burn the foliage, admits of the addition of Paris green, thus forming a combined insecticide and fungicide, and is withal a cheap remedy. The formula and method of preparation hiivo many times been given, but it should be noted that the strength has been considerably reduced, as, while some prefer to use so much as four pounds of copper sulphate and three pounds of lime to thirty-two gallons of water, particularly for the first application, half that strength (four pounds copper sulphate, throe pounds of lime, and 64 gallons of water) will givo fully as good results, especially for all after the first.

For use late in the season, whoro there is danger of the lime coating the fruit, modified eau eelosle (two pounds copper sulphate, two pounds soda carbonate, ono quart strong ammonia water, and 32 gallons of water), or ammoniaeal solution of copper carbonate (three ounces copper carbmato, three pints strong ammonia water, and 32 gallons of water arc preferable) ; but one application is all that will be desirable.

To secure the best results, the application should be made early in tho season, as one spraying before the leaves appear is worth a dozen after tho fruit is half grown. For most fruits, an application early in the spring before tho buds swell (it may bo done in the fall if there is more time), is desirable. Tho stems and branches at that time aro more or less covered with spores, and, as tho foliage is off, they can bo readily reached, and a small amount of material will suffice to, destroy them. It the disease is likely to. be troublesome it is a good plan to malm, a second application just before tho fruit, buds open, and to repeat it within a, week, after tho blossoms fail, although these last, two may bo combined in ono application,, to be made as soon as the trees are out oC bloom. As a rule not moro than five, applications need bo made to ward off the. disease (the last ones at intervals of two or throe weeks), and in favourable seasons two or three are all that will bo profitable with most crops, while very marked effects can be produced with'one.

In a general way wo may say that, by a thorough use of fungicides, nearly all the diseases of our fruits cau be kept in check. Decent experiments would seem to demonstrate that the curl of the peach leaf can be almost entirely prevented, although the cold wot weather, in which tho disease is most troublesome, is not favourable for tho use of fungicides. Tha brown rot, which not only destroys our peaches, plums, and cherries, but is often quite injurious to the leaves and branches of tho trees, can with care bo kept in check, although for the same reason it, like tho poach loaf curl, is a difficult disease to control. To secure tho best results, the diseased fruits should be. buried, and, after giving tho ground a. thorough wetting down at the time of the> first application, working it with soma kind of drag or cultivator to bury as many as possible of the spores. By thinning the fruits, so they will not touch one another, the rot can also be greatly reduced, and this should at any rate ho done to increase tho size of the remaining fruits.

While the use of fungicides will lesson the chances of the spread of the black knot, it should not bo entirely relied upon in fighting this insidious disease. As soon as a knot appears it should be cut off and burned. If this is done as early as October of the first season, before the greenish, velvety coat forms, it will ripen no spores; while if left until the following September, two crops at least will have been scattered. When upon the, trunk of a tree, when serious harm would be done in cutting off the knot, it can bo, pared off, and, by treating the wound with, tincture of iodine, the knot will bodestroyed. The fungicides can also bo used for thestrawberry leaf blight, which is often so destructive to some of our best varieties.. The application of Bordeaux mixture .fp--the plants in February, and agah as soon as the blossoms have fallen in the spring,, will render free from diseae varieties, that are very subject to it./' The scab of the apple a;d pear, and the leaf blights of the pear, ynir.oo and plum, can be readily controlic j’by sprayingbu^ as for other diseases^.itentirely success. ful the applications’ must be Tia'Jfl a*- ti proper time, ■ During the ‘ Ul ° plum trees often die because ej c in an unripe condition from the fact that the trees drop their 1- ‘ i *• summer. Hod thev V e<WCS aurl ? g ** Ti ~L \ , been sprayed, even JsiT(ld W baci^ e ’"■' ease ® rßt a PP eare d, they would have retained enough of their throu S h tbo winter in good the apple scab fungus is net so'ere enough to cause the leaves to drop, it destroys more or less of the tissues and greatly reduces the growth of the trees. The grape was one of tho first fruits upon which fungicides were used, and the more successful growers use the spraying pump freely. As with the disease mentioned above, so it is with nearly a'l others. If spraying is undertaken in time and is properly kept up they can be held in subjection and their terrors will bo lost.