218 



VEGETABLE GROWING PROJECTS 



While the potato aphis is generally prevalent, few areas have 

 reported outbreaks. In certain regions it causes severe damage, 

 sucking the plant juices, and wilting the plant. Leaves when 

 attacked curl downward, the blossoms are killed, and the tubers 



dwarfed. The lice are usually 

 of a green color, but some indi- 

 viduals are pink. Eggs are laid 

 on roses or other perennials in 

 the fall, but do not hatch until 

 the following spring. The stem- 

 mothers and their progeny live 

 on these plants for one or two 

 generations, and then migrate to 

 potatoes to breed until the ap- 

 proach of winter when sexual 

 forms migrate to the rose. Spray- 

 ing with Black Leaf 40, ^ pint to 

 50 gallons of Bordeaux mixture, 

 or with the same amount of Black 

 Leaf 40 and water to which 3 or 4 pounds of dissolved soap have 

 been added, may be effective. At least 100 gallons of the mix- 

 ture are required to cover an acre, the spray being directed upward 

 by angle nozzles, so as to drench the under side of the foliage. 



1. What is the cause of " pimply " potatoes ? CL : 316. 



2. 7s control practical in large potato fields? CL : 317. 



3. What are some other fl^a beetles on general crops f CL : 318-337. 



4. What is the life history of the Colorado potato beetle? 



CL : 145-146. 



Fig. 58. — Potato flea-beetle injuries. 



5. Summarize briefly its migration across the United States. 

 CL : 142-144. 



