Insect Injury 



II. Symptoms produced by Sucking Insects 



17. Minute holes accompanied by puckering of 

 the leaves, but without iasects present at the time : 

 bugs have punctured the young leaves and stem in 

 the bud. 



18. Curling and often discoloration of the leaf, 

 accompanied by the presence of greenfly (aphides), 

 or their cast skins — caused by the greenflies of apple 

 and plum (some species), cherry, etc. 



19. Spittle-hke spots on foHage of various kinds, 

 and on young shoots : the bug known as the cuckoo- 

 spit. 



20. Drops of a sticky consistence among flower- 

 buds and young leaves of apple (Apple Psyfla) and 

 pear (Pear PsyUa). 



21. Honeydew on leaves : greenflies or scale 

 insects. [Bees often visit plants for this honeydew, 

 and ants do the same, obtaining it straight from the 

 insects. Whenever ants are seen to be busy on plants 

 search should be made for greenflies or scale insects.] 



22. Black fungus growth on leaves : Fumago sp. 

 grows on honeydew, and is a sign of the presence of 

 greenflies or occasionally of scale insects. 



23. Flowers develop in a one-sided way, e.g. 

 chrysanthemums, buds grow only on one side ; 

 apples, and occasionally pears, show roughened 

 warts : they have been punctured by bugs during 

 their development. 



113 I 



