382 A Practical Hand Book 



Brushing infested twigs with a brush or broom wet with kero- 

 sene emulsion has been suggested as a treatment for this insect, 

 but winter spraying with about twenty per cent, kerosene emul- 

 sion has given the most successful results. 



Oak Galls. 



Though a large number of insects attack the various kinds of 

 oaks, few can ordinarily be regarded as serious pests. If cater- 

 pillars are feeding on the leaves, spraying with a stomach poison is 

 usually a sufficient treatment. Borers in the trunk can be handled 

 as suggested for the maple borer, and sucking insects can be con- 

 trolled by spraying where they are with a contact poison. Gall 

 insects, however, may cause perplexity, as neither of the methods 

 just named would seem to fit this case. 



It is very unusual for gall insects to be so abundant on a tree as 

 to render it liable to die. It is very common, however, for them to 

 disfigure the tree and thus lead to a desire for treatment. In cases 

 where galls are formed on the branches they are likely to become 

 permanent eyesores, and such branches should be promptly cut ofif 

 and burned. Elsewhere on the tree there is little which it will pay 

 to do, and patience will usually be rewarded in a year or two by 

 the disappearance of the galls, as their makers are gradually over- 

 come by the natural enemies of these insects. 



The Rose-leaf Hopper. 



This is a common pest on roses grown out of doors. During 

 the latter part of May and in June, numerous tiny young of this 

 insect may be found on the under side of the leaves, from which 

 they suck the juices, producing whitish spots, and if abundant 

 may cause the leaves to turn yellow and drop ofT. At first these 

 insects cannot fly, though they can hop freely, but after they 

 have become adult, disturbing the bush may start them flying in 

 clouds. These adults are about an eighth of an inch long and pale 

 yellow in color. 



Thorough spraj'ing of infested plants with kerosene amulsion or 

 soap is quite effective as a treatment, provided that the spray be 

 directed against the undersides of the leaves and be driven rather 



