5^4 Journal of Agriculture. [lo Sept., 1909,. 



TREATMEXT OF ORCHARD PESTS. 



p. J. Carmody, Chief Inspector of Orchards. 



For all })ractical purposes, the insect pests of our orchards may be- 

 divided into two classes, viz., chewing insects and suctorial insects. On 

 this classification will depend their treatment. Wherever possible, the 

 former class should be controlled by internal poisoning, and the latter by 

 insecticides that destroy by coming into direct contact with the insects 

 themselves. Among the chewing insects the codlin moth reigns supreme, 

 and can be most effectively kept in subjection by means of arsenical sprays. 

 As the operation of spraying with these is fraught with considerable risk 

 to foliage, growers should be guided in their use by the following hints : — 

 {a) No preparation should be used as a general spray without first 



testing it on a tree (or portion of a tree) of the different 



varieties to be treated, unless the grower has had previous- 



experience with that particular brand. 

 {b) Some varieties are more susceptible to arsenical influence than 



others, the Bismarck being the most noticeable in this re 



spect in my experience. 



(c) Weak, stunted, water-logged trees are less resistant to this 



burning than young vigorous ones. 



(d) In moist or foggy weather, this sprav is far more injurious than 



when the weather is warm and equable. 



{e) Water used in mixing the sprays should be free from anv acids 

 that will act as a solvent on the arsenic. 



(/) Vessels, pumps, nozzles, hose, &c. , should be thoroughlv clean 

 and free from Bordeaux mixture or anv active agent that 

 would cause mechanical or chemical changes to take place. 



(g) The safest sprays are those having the least amount of soluble 

 arsenic in their composition. 



(//) The spray should be continuously and thoroughly agitated from 

 the bottom of the pump up to the surface. 



(/■) Repeated sprayings with arsenic, when not whollv insoluble, 

 often set up a kind of chronic derangement of the cellular 

 tissues of the leaves not at fir.st noticeable, but which causes 

 the leaves to prematurely turn yellow and fall off. 



(;) Extreme care should be exercised with the handling, storing, 

 and application of these sprays. They should not be used 

 at the ripening stage of fruit, nor for some time previous to 

 its being pulled from the trees. 



Spraying. 



Codlin Moth. — In spraying for the codlin moth, it is necessary to- 

 apply the first application when the petals are falling and before the calyx 

 of the fruit closes. The second spraying should be given when the eggs 

 are on the fruit, so that the grower will require to be keenlv observant for 

 this period. The egg is readily discernible and is about the size of a 

 pin's head, and of a yellowish white colour. Two or three more applica- 

 tions at not more than fortnightly intervals will suffice to keep the first 

 brood in check. With late varieties, it is imperative to sprav again towards 

 the latter end of February. Of course, e\erv grower recognises that no 

 detailed system of spraying can be laid down, as the habits of the moth'- 



