|
worse than the disease; (3) a thorough job must be done or else thewhole job may have to be done over at too late a season to secure thebest results; (4) the correct time must be picked or a rain stormmay undo the whole work within a few hours; (5) the spray muststick to the plant long enough to be of some use, especially in the caseof poisons. The various forms of sprays may be classified in four different ways:according to the season of spraying, the kind of chemicals used, theform in which the chemical is applied, and the kind of plants sprayed. Seasons for Spraying. The seasons for outdoor spraying are two:the summer or growing season, and the winter or dormant season.Summer sprays are invariably not applied so strong as winter sprays,because the bark on the new shoots as well as the leaves would beinjured by a spray of a strength which would not only be entirely safe,but advisable to use when a plant was dormant. Dormant sprays aremostly confined to those applied for protection against vegetableparasites and those intended to destroy scale insects. Some usefulwinter work is often done in the destroying of egg masses and cocoonsby torches and the application of creosote or other strong paints byhand in small quantities; but this is not, strictly speaking, spraying.Summer spraying includes nearly all the methods used in the dormantseason, with the spray made more or less dilute, dependent upon theexact season, as well as all the other forms of sprays. It should benoted that dormant spraying may be done at almost any time after theplants become dormant in the autumn and until they start growth inthe spring; but it is not advisable to attempt to spray during freezingweather, nor too early in the winter, because in the latter event muchof the benefits of the spray will be lost through the subsequent winterstorms. If dormant spraying is delayed until nearly spring somebeneficial results may be expected to extend into the summer, whichwould otherwise have been lost. Summer spraying, on the contrary,must usually be done at some precise time in order to secure the de-sired results, though this is not always strictly necessary. |
|||
|
