350 FRUir INSECTS 



about one half or more of the white portion projects from 

 the sht, making it rather easy to locate the eggs (Fig. 309). 

 There is but one generation a year. 



Treatment. 



The nymphs may be destroyed while small by a thorough 

 application of kerosene emulsion diluted with five parts of 

 water. This is probably the most practicable means of fighting 

 the pest while in the nymphal stage. The pruning and burning 

 of the tips in which all the eggs are laid is an efficient means 

 of keeping the pest in check. When occurring on herbaceous 

 plants, probably the ])est method is to capture the bugs by 

 jarring them into a dish partly filled with kerosene and water. 



Referen(^e 

 Cornell Agr. Exp. Sta. Bull. 58. 1893. 



The Currant Plant-louse 

 Myzus ribis Linnaeus 



In the Northern states and Canada the foUage of currants 

 is very commonly distorted and discolored by the presence of 

 yellowish-green plant-Hce on the under side of the leaves. Red 

 currants are most subject to attack, but black currants and 

 gooseberries are sometimes infested. The insect is a native 

 of Europe, where, in addition to the cultivated varieties, it also 

 infests the wild alpine currant. It was probably introduced 

 into America in the early part of the nineteenth century, but 

 did not attract attention until about 1857. 



The shining black, cucumber-shaped eggs, attached to the 

 bark of the new growth, hatch soon after the leaves open. The 

 young Kce crawl to the leaves and begin feeding on the under 

 surface ; these lice hatched from the eggs are all females and 

 are known as stem-mothers. When mature they give birth to 

 living young, and each individual is soon surrounded by a nu- 



