CONFERENCE ON SPRAYING OF FRUIT TREES. 



331 



we had better rely on the wash we know will do good. For the destruction 

 of caterpillars of all kinds there are used what are called arsenical washes. 

 The first used was Paris green, which often burnt up the foliage, and 

 always did more or less damage. London purple was also used, but is not 

 of very much account. Then came into use what is known as arsenate 

 of lead. There are growers who have used arsenate of lead prepared on 

 an old formula, which scientifically we are told is absolutely wrong, who 

 found that their trees were damaged. Unless you get the formula right, 

 the arsenate of lead may do a certain amount of damage (I have never 

 known it, but I know one or two growers who state so). There are two 

 forms in which arsenate of soda can be obtained, and in mixing the wash 

 one has to find out exactly what form of arsenate of soda one is using. 

 If we know that, well and good ; mix one's own wash by all means ; but 

 when we can get this wash guaranteed made up ready for use it is as well 

 to buy it. The wash is made by mixing arsenate of soda and acetate of 

 lead and water ; if we have the arsenate of soda in what is known as 

 pure crystalline form, then we use 3^ oz., and acetate of lead 7 oz. to 

 every 10 gallons of water. If we have the arsenate of soda in what is 

 known as the " dry " form, and used 3f oz., we should produce a wash that 

 would cause a certain amount of scorching of leaves, so we have to 

 reduce it to 2 oz. Arsenate of lead is fatal to all caterpillars. It has the 

 advantage over Paris green that it is of a very strong adhesive nature, 

 and at the same time it has greater killing power than Paris green or 

 London purple ; this is so well known now that it is scarcely necessary 

 for me to refer to it. When should we use this arsenical wash ? I believe 

 in a large number of plantations it is necessary now and again. If we 

 grease-band our fruit trees, which, we know, is a certain way of preventing 

 the winter moth, which is far worse than any other caterpillar, we have 

 only to spray with the arsenical washes when we get any particular pest 

 present, that is, a pest not affected by grease banding such as the Tortrix 

 moth and lackey moth. If we see these in the early stages, then we 

 should spray ; but do not go through all the plantations just because 

 arsenical wash will kill caterpillars. Do not spray the plantations whether 

 the caterpillars are there or not, because by so doing you are undoubtedly 

 giving a set-back to the tree, because no tree will stand constant spraying, 

 and you are doing no good if the caterpillars are not there. But if you 

 have an attack of winter moth where you cannot grease- band, then spray 

 the trees at the beginning of the attack when the little caterpillars are 

 seen first of all in the early spring, before they are shut up in the leaves 

 and the blossom trusses where you cannot get at them ; then one spraying, 

 if done thoroughly, should be quite sufficient. If you have in your 

 plantation the codlin moth, which is not so destructive as formerly, trap 

 the maggots by tying old manure sacking around the trees for the larva* 

 to spin up under, and you will get rid of a large number. Then if you 

 have the creature still persisting, a second application of this arsenical 

 wash may be necessary soon after the blossom has fallen. But do not 

 spray just because the creature may come, or I am afraid you will find 

 a large proportion of the profits you hope to make will be gone in a 

 chemical bill. 



Another subject I wish to call your attention to is ni connection with 



