36 Journal of Agriculture, Victoria. [10 Jan., 1919. 



insects live under their webbing on tbe back of tbe leaves, but many, in 

 the different stages of development, infest the upper surface as well. 

 They make numerous punctures in the epidermis of the loaves, through 

 which the juice is abstracted by means of their sucking organs. The 

 trees are thus deprived of much of their nutriment, and many of the 

 leaf stomata are destroyed; this greatly disorganizes the process of sap 

 elaboration, and militates against its equitable distribution. As the 

 season of growth advances, the vitality of the leaves becomes corre- 

 spondingly impaired, creating a most unfavorable condition for the 

 maturing apples on the trees, as well as operating against the proper 

 development of fruit buds for the succeeding year. 



The best time to deal with red spider is while it is in the egg stage, 

 and, as this occurs during the dormant period, red oil emulsion may be 

 used with good effect. A strong solution may be used at this time, 

 and the spray can be applied when the leaves have fallen. Tobacco 

 water and soap solution make an effective spray against the insects on 

 the leaves. The nozzle requires to be directed upwards when spraying, 

 • so as to drench the under side of the leaves, where the spiders are usually 

 most numerous. 



San Jose Scale (Aspidiotus perniciosus) . 



In San Jose Scale the fruit-growers have another formidable and 

 destructive pest, which, since its introduction into Australia, has become 

 widely distributed. It was probably introduced to this country on 

 nursery trees, and by this means also it spread through the States of 

 the Commonwealth and to New Zealand. The careless selection of 

 buds and scions is also responsible for its appearance in so many parts 

 of the State, while, in an infested area, birds afford the most likely 

 means of locomotion from orchard to orchard, and from tree to tree. 

 The laiwse become numerous on infested trees at the expiration of the 

 period of latency. At this time probably numbers of these attach 

 themselves to the bodies of birds visiting the trees, and crawl off on to 

 the branches of others subsequently visited. The scales, which protect 

 the insects, being small, circular, flat, and almost the colour of the bark, 

 are, except to the practised eye, difficult to detect, especially if the 

 infection be only of recent origin and slight. When the insects appear 

 on the fruit, however, their identification is simple, as the pink spots 

 caused by the larvse, and on which the scales rest, indicate their 

 presence. 



The photograph of the ripe London' Pippin apple in Plate 187 illus- 

 trates this condition, the dark circular spots represent the pink markings, 

 in the centres of which the young scales appear as grey specks. Similar 

 colouring of the bark occurs where the scales rest, but the surface of the 

 coloured part not being as extensive as that on the fruit, it cannot, 

 except in cases of severe infection, be seen until the scale is removed. 

 The colouring in the spot begins to appear when the larva inserts its 

 proboscis in the bark or fruit, as the case may be, and develops while 

 the sucking out of the juice continues. 



Trees or portions of trees badly infested with scale soon assume a 

 sickly appearance, the bark becomes rough through the action of the 

 insects, and if it be sliced off its general unhealthiness is suggestive of 

 sap contamination. Red oil is very effective against San Jose Scale, 

 yet its eradication from an orchard proves difficult. This is owing to 



