CONFERENCE ON FRUIT GROWING-. 



25 



strength to burn through the scale without the risk of serious harm to the 

 tree. The eggs of the Mussel Scale hatch out in June, and the active 

 young soon commence to excrete white waxy threads which make them 

 very conspicuous objects, although very minute. For some five weeks 

 after this, the scale is very soft and can be destroyed by paraffin emulsion. 

 The eggs do not all hatch out at once, the incubating period taking at 

 least two weeks. Spraying should not then take place until about three 

 weeks after the young scale insects are first noticed. There is no doubt 

 that paraffin is the only certain remedy for this and other Coccid pests. 

 But it has to be used with considerable care, as no one can tell what 

 effect it has, unless very dilute, upon the tree. 



It has been used for scrubbing the bark for Mussel Scale at the rate 

 of 1 gallon of oil and 5 lbs. of soap to 10 gallons of soft water. The scale 

 is at once killed, but this strength is too great, for in an orchard I have 

 recently treated a few trees have been injured. It was found later that 

 the same quantities could be used to 50 gallons of water with complete 

 success. The trees I refer to numbered some 300, all of which had been 

 heavily sprayed with caustic wash and lime-washed in winter, and yet all 

 the scales remained alive and hordes of young were produced. 



In the winter this paraffin emulsion will have similar effect and would 

 not be so liable to harm the trees, but I believe there will always be 

 danger in using paraffin or any other mineral oil. As you know, they 

 sometimes recommend crude petroleum treatment in America, but its 

 disastrous results are only too well known. 



Lime, salt, and sulphur wash I have found successful if applied in 

 autumn, but not of sufficient benefit to further advise as a winter 

 wash. 



As far as we can see at present, there is no doubt that paraffin 

 emulsion employed in the early autumn is the most efficacious scale 

 remedy, unless we have recourse to hand-scrubbing, and then a strong 

 soft-soap solution would be sufficient when the young are hatching out. 



The Apple- sucker. — The Apple-sucker, although widely distributed 

 on the southern, central, and western districts of Britain, is really only a 

 serious pest in Herefordshire, Worcestershire, and Kent. 



In those counties it has been harmful for some time, but it has 

 undoubtedly increased very considerably during the last ten or twelve 

 years. Like the Mussel Scale, its life-history is so well known that no 

 further investigation is necessary. 



What we learn from its life-history of importance are the following 

 facts : first, that the eggs are laid irregularly in the autumn, on the 

 Apple, the date of egg-laying varying in different localities and in different 

 seasons ; secondly, that these ova hatch out irregularly in the spring, 

 the period of incubation lasting for two weeks ; thirdly, that the larvae 

 very soon enter the buds after they have hatched, and are for some time 

 completely protected by them ; fourthly, that the adult insects live un- 

 protected on the leaves of the Apple-trees from July until they deposit 

 their eggs in September and October, and even November. 



These active hopping adults vary much in colour ; when egg-laying is 

 about to take place they lose their bright green hue and become yellow or 

 marked with red, black, or yellow, which will distinguish them, together 



