30 



the till}- iour-whiged parasites like the uiie shown in hgure IG. These little 

 creatures in their larval stages feed both upon the insect itself under the scale and 

 upon the eggs, and when full grown come out from tiny round holes which they 

 make near the centre of the scale, and which can easily be seen with a hand lens. 

 There are several species of these parasites, but the only one T know of at present 

 in Ontario is shown in figure 16. In some localities as high as 50 per cent, or 

 more of the scales have these small holes, and though they do not destroy all the 

 eggs beneath a scale they must be of considerable aid in keeping down the rate of, 

 increase. 



MEANS or CONTROL. 



The lime-sulphur wash, properly applied, will readily control this scale. 

 Two sprayings should be given for the best results, the first at the strength of 1.030 

 specific gravity hydrometer reading, or about one gallon of the commercial lime- 

 sulphur diluted to ten gallons with water and applied shortly before or as the buds 

 are bursting; the second at the strength 1.009 specific gravity, or the commercial 

 diluted one gallon to thirty or thirty-five with water and applied just after the 

 blossoms have fallen. Two pounds of arsenate of lead should be added to every 

 forty gallons of the mixture for this application, as this is the proper time to spray 

 for the Codling Moth, Plum Curculio and Lesser Apple-worm. Of these two appli- 

 cations the first is far the more important, but does not always give uniformly good 

 results. Sometimes it will destroy almost all the eggs or prevent the larvae if they 

 hatch from escaping from the covering scale, at other times a large number hatch, 

 though most of these soon die, killed apparently by the spray mixture that remained 

 on the tree. There is no doubt that this one application repeated each year will 

 itself soon free the trees from the pest, but the results are accomplished more 

 quickly by the aid of the second application at the time stated above. This will 

 kill most of the larvae that are already hatched, and will leave the bark covered 

 and so repulsive to any that may hatch a few days later. The great point, how- 

 ever, in favor of using lime-sulphur in preference to any other known remedy is 

 that this wash not only destroys the Oyster-shell Scale, but many other things as 

 well ; for instance, the first application before or as the buds are bursting will also 

 control San Jose Scale, Blister Mite, Tent Caterpillars— these must be hit soon 

 after hatching — but also helps to ward off such diseases as Scab and Black Eot 

 Canker. The second application, combined with the arsenate of lead, is always 

 required to control Codling Moth, Plum Curculio, Lesser Apple Worm, Scab and 

 Leaf Spot. For this spray lime-sulphur has proven itself even more satisfactory 

 than Bordeaux mixture as a fungicide, because it keeps off the Scab on the fruit 

 without causing the serious russeting and even cracking of apples commonly result- 

 ing from Bordeaux mixture. It is clear, therefore, that these two applications with 

 these mixtures should be given even if there were no Oyster-shell or San Jos6 Scale 

 to combat. In addition to these, our best growers give an intermediate application 

 just before the blossoms burst, and most of them use the weak lime-sulphur Iiere, 

 too, along with two or three pounds of arsenate of lead. Bordeaux, however, may 

 be used in place of the lime-sulphur, and is possibly even more effective at this 

 stage as a fungicide. This application is important for the destruction of early- 

 feeding caterpillars and for the control of scab. 



As in the case of the San Jose Scale, old trees should be pruned before spraying 

 and the rough bark scraped off. If the trees are not vigorous, a liberal dressing of 

 barnyard manure or cultivation in May and early June will help them to recover 

 more quickly from the effects of the scale. 



