ON KEEPING ORCHARDS CLEAN. 



35 



will stay in a " mossy " orchard when otherwise they would leave 

 it and shelter elsewhere ; these spend the day in repose, sitting on 

 lichen &c., which their colour scheme fits in with, and it is helping them 

 to let the lichens grow. 



In the second, the lichens and moss give shelter to many tender 

 insects ; the Gold-tail larva in winter, the Currant Shoot-borer, the 

 Codling larva, the Apple-leaf Miner Moth, the Blossom Weevils and 

 Twig Weevils all hibernate in such a way if they can. 



Removing the moss and lichen makes things harder for them. 



Lastly, a winter wash may reach tender hibernating insects under 

 the bark scales, in cracks, among the moss &c. ; the young Brown- 

 tail Caterpillars in their nests, the Gold-tail larvae on the bark, the 

 Currant Shoot-borer on the twigs, the young Bud Moth larvae in 

 their cases, the Ermine larvae under the egg-cases, the Pith Moth 

 larvae under the rind near the bud are destroyed by a suitable wash 

 applied during the dormant period. Woolly Aphis on the shoots 

 and in the bark, the Mussel Scale under the flakes of bark, the Brown 

 Scale, the Oyster-shell Scale, the Brown Currant Scale are sucking 

 insects which can be checked in this way. The Gooseberry Mite 

 and the Pear and Plum Leaf-blister Mites are hiding under the bud 

 scales, and are killed by a suitable wash. 



Winter washing is a very important operation, and is fully justified 

 by its results. What wash to use and when is a matter largely of 

 local conditions ; what suits one district does not suit another ; 

 there are many good washes, both those sold ready for use and those 

 that can be made up as wanted ; and the application of a suitable wash 

 should be a part of the routine in every orchard and plantation in 

 the country. 



A separate form of treatment is that known as a winter cover-wash, 

 in which the object is to coat the tree with a wash that will remain 

 on in the winter, will prevent moss growing, kill hibernating insects, 

 fill up cracks, and particularly kill eggs of Apple-sucker and Aphides. 

 The ordinary caustic winter wash probably kills very few eggs, 

 whereas an efficient cover-wash may kill many. The Society has 

 lately conducted a trial of winter washes, and a valuable paper on 

 " cover-washes " has just appeared.* 



8. Control Wild Food-Plants. — A great number of our pests 

 are casual, live on a variety of wild plants and attack fruit-trees 

 sporadically, and just because they happen to be there. That is the 

 great difficulty in preventive entomology in this country ; the pests 

 are so varied, come so irregularly and are often not destructive enough 

 for anyone to know them all or to take them seriously ; but their 

 aggregate effect is large and the total loss to the marketable crop 

 due to these many insects is very considerable. I have no figures 

 available, but I really wonder if we do harvest in a perfect marketable 

 condition more than one-third or a half of the fruit that the trees 

 yield. 



* See Lees, Ann. App. Biol. I. p. 351. 



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