28 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



freely exposed in the spring. In the autumn, however, it is different, for all 

 three of the plant lice, like those on other fruit trees, are exposed on the 

 under sides of the leaves and shoots. These are the sexual forms which 

 deposit eggs in October and November. This is the time when we can 

 do most good by spraying, and so prevent the trees from being attacked in 

 the following year. 



By this autumnal spraying we can kill aphis, apple-sucker, and mussel 

 scale all at once, and at this time we can use a strong paraffin emulsion, 

 as the leaves cannot then be harmed and at no other time can we cope 

 with them collectively. 



The Winter Moth. — There are many leaf -eating caterpillars on fruit 

 trees which are destructive, but undoubtedly the worst is the winter moth 

 (Cheimatobia brumata). The life-history of this pest is too well known 

 to refer to here ; it is now well recognised that we can prevent winter 

 moth attack by "grease-banding." Where the winter moth is the chief 

 culprit, spraying should not be necessary if we adopt that process. 



One has, however, frequent complaints that grease-banding is not 

 effectual. I venture to think that if the caterpillars are examined the 

 majority will be found to be other than winter moth larvae ; there are 

 several small moths known as Tortrices which feed in their caterpillar 

 stage on foliage, blossom, and buds. These Tortrices have winged 

 females ; and against this pest grease-banding is of no avail. The only 

 remedy we have for these insects is spraying with arsenites. 



Where we have numbers of these insects is it worth while to grease- 

 band ? for the same spray will kill tortrix and winter moth alike. In both 

 cases the spray must be put on at the right time, before the larvae can 

 enter buds or spin up leaves and blossom tufts. 



An early spraying just as the buds are bursting will do more good 

 than later, when we see the damage being done. Young larva? are much 

 more easily killed than old ones, even when the latter are freely exposed 

 on the leaves. 



Winter moth and Tortrix caterpillars hatch out from the middle of 

 March to the middle of April according to the season and locality, so 

 that between these dates should be the time to spray for these pests. 



Arsenites. — The form of arsenic chiefly used in this country is Paris 

 green. Reports concerning its efficacy are very varied. I have known 

 people resort to jarring the larvae off nuts owing to the failure of this 

 poison. Failures are usually due to the fact that Paris green has but 

 slight adhesive power and is at once washed off by showers. Moreover, 

 Paris green is seldom used without some damage being done to the foliage, 

 often to a serious extent. 



However, we have an arsenical spray — arsenate of lead — which, so 

 far as I know, has not been found to harm foliage or blossom in the least, 

 even at a much greater strength than is required "to kill the larvae. 

 It has two other advantages — namely, a greater killing power, and its 

 much more adhesive nature than any other arsenite we know of. It will 

 be interesting to hear the results growers have obtained with this wash 

 which I have found so much more efficacious than Paris green. 



The Codling Moth. — The codling moth is another pest that calls for 

 special comment. There is only one fresh thing that we want to find 



