194 



VEGETABLE GROWING PROJECTS 



is single brooded. It inserts eggs into the thickened stem and 

 larger leaf veins, and these hatch about fifteen days later, when the 

 nymphs work into the heart of the plant. Little progress has 

 been made in the control of the insect, and therefore of the disease. 



As a commercial practice. 



spraying appears to be un- 

 profitable and of doubtful 

 efficiency. 



The common name " leaf 

 miner " given to the spinach 

 leaf miner describes the nature 

 of its larval work. The larva 

 eats into the tissue of the leaf, 

 making a thread-like mine 

 which by continued eating is 

 enlarged like a blotch. This leaf injury dwarfs the roots or 

 spoils the leaves if used for greens. The adult fly, a two-winged 

 fly, appears in the fields early in the spring and deposits eggs 

 on one side of a leaf. These hatch, and the young larva, 

 working in the leaf, becomes mature in about a week, when it 

 deserts the leaf and enters the soil to pupate. Clean culture 

 may be a means of control. There is no satisfactory remedy. 



FiQ. 52. — Spinach and beet leaf miner. 



1. Why is the spinach aphis Stick a serious pest f CL: 105-106. 



2. What is its life history f CL : 105-106. 



3. How can it he controlled? CL : 107. 



4. Describe an improved type of sprayer. 



5. How can radishes be protected from root maggots? CL : 36. 



