210 



THE NURSERY-MANUAL 



Often the aphids secrete a sweet liquid known as honey-dew in 

 which a black fungus develops and gives the infested foliage 

 and twigs a sooty appearance. The 

 green colored species (Aphis pomi and 

 Aphis sorbi) are commonly found on apple 

 and quince, while cherry buds are often 

 attacked by a black-colored species (Myzus 

 cerasi) . 



Control. The aphids lay small shiny 

 black eggs on the twigs in autumn. 

 Spraying in October with tobacco extract, 

 f of a pint in 100 gallons of water, adding 

 3 pounds of soap to each 100 gallons to 

 make the liquid spread better, will kill 

 many of the aphids before the eggs are 

 laid. Aphid infestations can be greatly 

 reduced by spraying with the above solu- 



Fio. 221. Newly ... 1 u , u . xU 



hatched aphids cluster- tion just after the eggs hatch in the spring ; 

 ing on an opening apple the first eggs hatch about the time the 

 buds show green. When the aphids appear 

 in abundance, it is advisable to dip the infested branches into 

 the insecticide. The leaves are usually curled and it is difficult 

 to hit many of the aphids by spraying. Infestations of aphids 

 on apple, pear and quince stock should receive immediate 

 attention as often as the.se insects are important in the dis- 

 semination of fire-blight bacteria. 



WOOLLY APHIS. The woolly aphis on apple, pear and quince, 

 is common in the nursery. 



The reddish-brown aphids appear on the trunk and branches 

 and roots as bluish-white cottony patches. The same species 

 also passes a part of its life history on the elm, infesting the 

 leaves and causing them to curl. The woolly aphis sucks its 

 food from the bark and often causes abnormal growth or galls. 



