36 



pound in 6 gallons of water, may be used instead of Black Leaf 40, but should not 

 be combined with lime-sulphur. It is almost useless to spray after the leaves have 

 become curled because it is then impossible to hit all or nearly all the aphids. 



Eed Spiders {Teiranyclius himaculatus) . — Red Spiders are mites that feed 

 on the under surface of the leaves of numerous plants. They have sucking mouth 

 parts and cause currant leaves to become brownish or reddish-yellow in color and 

 therefore unhealthy in appearance. Such leaves in dry weather, when the plants 

 need them most, dry up and die. The mites have the habit of spinning a very fine 

 web on the undersurface of the leaves, beneath the protection of which they feed 

 and lay their eggs. Eed Spiders are not all red, as one would expect; frequently 

 most of them are a pale green or nearly transparent whitish color. They can just 

 be seen with the naked eye. The eggs are like little glistening drops of dew. The 

 spiders winter in the soil around the base of the plants. 



Fig. 22. — Currant leaves curled by aphids. (After Close.) 



Means of Control. — If lime-sulphur is used for the various spray applications 

 mentioned above and the under surface of the leaves is well covered there will be 

 little trouble from this pest. Wet weather also helps to control it, as the mites 

 thrive best in dry seasons. 



San Jose and Oyster Shell Scales. — Currant bushes frequently, and goose- 

 berry bushes sometimes, are severely attacked by either the San Jose or Oyster Shell 

 Scale. If no remedial measures are taken the former of these insects will soon kill 

 affected plants, and the latter will weaken them and occasionally cause their death. 

 For a full description of the appearance and habits of these insects see Bulletin 

 No. 219. 



Means of Control. — Prune the bushes out well so that every part can be thor- 

 oughly sprayed and use lime-sulphur, specific gravity strength 1.032 to 1.035 (com- 

 mercial lime-sulphur 1 gallon to about 8), a little while before the buds burst. A'ery 

 badly infested bushes should receive two applications before the buds burst. 



Many other insects and diseases attack currants and gooseberries in Ontario, but 

 as they seldom do mnrh rlamaire it ha> not soomed desirnhle to give an account of 

 them here. 



