220 INSECTS AFFECTING FIELD CROPS 



Injury. Leaves of the second crop of tobacco are injured by 

 this pest sucking the sap from the leaf tissue, causing it to yellow 

 and rendering it nearly worthless. 



Control. Tobacco extracts applied by spraying both upper 

 and lower surface of the leaves appear to give the best results. The 

 strength to be used is given on the containers. Early application 

 at the very first appearance of the insects is desirable. 



Tobacco Leaf-miner or "Split- worm." The adult of this 

 insect (Phthorimola operculella Boisd.) is a small moth whose 

 wings measure about one-half an inch from tip to tip. The female 

 lays its eggs upon the leaves, and the small caterpillars bore into 

 the body of the same, causing discoloration and sometimes a mis- 

 shapen leaf. The gray blotches due to the miner in leaf tissue have 

 been thought by some growers to be a disease and have been 

 referred to as " weather rot." The caterpillars do not remain con- 

 stantly between the upper and lower surface of the leaf, but may 

 emerge and, after crawling about the surface, enter at a new place. 



Control. Destruction of all leaves made worthless by the pres- 

 ence of the insect is advised. Destruction of all weeds in the 

 spring, particularly horse nettle, upon which the insect feeds, will 

 do much to reduce its numbers. 



Tobacco Flea Beetle. This small brownish beetle (Epitrix 

 parvula Fab.) is abundant in almost all tobacco-growing districts 

 in the United States. When abundant its attacks cause the leaf 

 to exhibit small dry spots, which grow larger, and eventually the 

 leaf becomes full of small holes. These afford entrance to fungous 

 diseases. Eggs are laid at the base of the plant, and the young 

 grubs feed upon the roots. Plants of the nightshade family are 

 attacked also. 



Control. All weeds, especially those belonging to the night- 

 shade group, should be kept off the ground. Particular attention 

 should be given to the edges of the field, fence rows, etc. Clean 

 cultivation is most important. 



Cut-worms. Several species of cut-worms attack tobacco. 

 These are generally well controlled by the use of a poisoned bran 

 mash made by mixing Paris green and bran until the latter is 

 decidedly green in color ; then add water and sweeten with molasses 

 or syrup just before using. This bait may be placed in a ring 

 around each plant and a short distance from the plant, or small 

 amounts placed at frequent intervals among the plants. Care 

 should be taken not to place this bait too close to a plant, for bring- 



