CERTAIN ELEMENTS IN NURSERY PRACTICE 215 



Control. An application of freshly slaked lime or powdered 

 ar senate of lead will destroy the slugs. The dust mixtures 

 employed in the control of pear leaf-spot or yellow-leaf of cherry 

 will also kill them. 



CURRANT WORMS. The green currant worm (Gymnonychus 

 appendiculatus) and the imported currant worm (Pteronus 

 ribesii) are often destructive on currant and 

 gooseberry bushes. These worms appear on 

 the bushes two or three weeks after the leaves 

 develop in the spring, and if numerous they 

 are able to strip a bush of its leaves within a 

 few days. 



The imported worm is about -f inch in 

 length, green in color with black spots. The 

 green worm is smaller, has a blackish head 

 but lacks the black spots. There may be 

 three or more broods of the green worm during FIG. 226. Pear 



slugs at work. 



the summer. 



Control. Applications of a dust mixture or a spray solu- 

 tion containing ar senate of lead will check these insects. The 

 treatment recommended for the leaf-spot diseases on currant 

 will also control the worms if lead arsenate is added to the 

 fungicide. 



