148 INSECTS AFFECTING VEGETATION 



Leaf-Hoppers. A number of species of leaf-hoppers feed on 

 the leaves of the beet. All are small, rather slender, and all jump 

 on the slightest provocation. They suck the sap from beneath the 

 surface of the leaves, leaving a small dead spot to mark each punc- 

 ture. This would ordinarily amount to little, but when the insects 

 come in swarms, as is often the case, the aggregate amounts to a 

 good deal. It is not possible to control these pests by spraying with 

 poisons, as they pierce beneath the surface for their food supply. 

 The contact insecticides will kill a certain proportion of them, but 

 no spray yet devised is satisfactory unless used when the pests are 

 small. They pass the winter in rubbish, under leaves, etc., there- 

 fore collect and burn all rubbish after cold weather sets in. 



Grasshoppers. When, from time to time, grasshoppers attack 

 the beets, they should be killed by poisoned baits, provided of 

 course, that such baits may be used without danger to stock or 

 poultry. Criddle mixture, a mixture of arsenic, salt and horse- 

 manure, is highly recommended by several who have tried it. Bran 

 and arsenic, or paris green and bran, has the disadvantage that it is 

 readily eaten by birds and poultry. For a further discussion of 

 grasshoppers see Insects of Sweet-corn. 



Beet Web-Worm. From time to time we meet the beet web- 

 worm, an insect that, on several occasions, has been very severe in 

 its attacks. The eggs of the web-worm are laid on the leaves, and 

 the larvae that come from them attack the foliage, either spinning 

 small webs among the young and tender shoots at the center of the 

 plant, or else feeding on the underside of the larger leaves, either 

 protected by a small web of silk or else exposed, with no protection 

 whatever. The caterpillars are pale yellowish-green, or reddish- 

 yellow in color dotted with small black points, each of which bears a 

 hair. They are about three-fourths of an inch in length. The head 

 is yellowish-brown marked with brown spots; the prothoracic shield 

 is somewhat lighter in color. The backs of the first two segments 

 each bear four black dots; segments three to eight each bear six 

 black dots, arranged in two triangles. Segment nine has one larger 

 median spot with two smaller lateral ones and segment ten has the 

 anal shield, dirty yellow in color, marked with brown spots. The 

 under side is marked somewhat similarly with dirty spots, each 

 spot being bordered indistinctly with pale. The legs are pale with 

 darker markings. 



The pupa of this moth is buried in the soil. The larva spins a 

 slender silken tube about three-quarters of an inch long, and in this 

 tube the pupal stage is passed. In the early broods the pupal stage 

 is of short duration, but the members of the last brood remain in the 

 tubes over winter. There are several generations each year. 



Spray with paris green on the first appearance of the larvae, 

 using lime as indicated in the directions for preparing insecticides. 

 Use one pound of the poison to one hundred and seventy-five gal- 

 lons of water. Plow the field after harvesting the beets, so as to ex- 

 pose the pupae to the birds. In spraying, use a nozzle set at right 



