Leaf-eating Beetles Larger Sugar Beet Leaf-beetle or Alkali-beetle 



exceptions where the larvae are root feeders. The Colorado potato-beetle 

 is the best known representative of this family. 



Several leaf-beetles feed upon sugar beets and under certain con- 

 ditions do considerable damage to the crop. The principal species of 

 this family, together with other leaf-eating beetles attacking sugar beets 

 in the Great Plains area, are discussed in the following pages. 



(a) LARGER SUGAR BEET LEAF-BEETLE OR ALKALI-BEETLE 



(Figs. 1 to 5, Plate VII, Page 23) 



In Northern Colorado this beetle is known as the "alkali-beetle" 

 or "alkali-bug", from the fact that it breeds most freely on the weeds 

 growing on low, damp ground where the alkali is brought to the surface 

 by seepage. In some other parts of its range it is known as the "French 

 bug". 



NATURE OF INJURY 



Both the larvae and the adults damage sugar beets. Injury usually 

 occurs on the border of fields next to waste land which is damp and con- 

 tains an excessive amount of alkali. The adults are very active on the 

 wing and often appear in swarms in the center of fields or at considerable 

 distances from low wet ground. When few in number their work appears 

 very similar to that of the flea-beetles only that the holes in the leaves 

 are larger. (See Fig. 1, Plate IV, Page 17). In severe cases nothing but 

 a network composed of the larger veins of the leaves is left and the leaf 

 becomes brown and shriveled. 



METHODS OF CONTROL 

 Spraying or Burning Weeds 



When beets are planted near low, damp ground the weeds on this 

 waste land should be watched closely in early summer. If alkali-beetles 

 and their larvae appear in numbers the weeds should be sprayed with 

 Paris green or straw should be scattered among them and burned. 



The destruction of the beetles and larvae at this time will prevent 

 their migrating into the beet fields and will also reduce the number of 

 eggs laid later. 



Spraying Crop 



In case the beetles and larvae have already begun to damage beets, 

 Paris green should be applied as a spray, using 4 pounds to 100 gallons of 

 water. Many times it happens that only a small portion of the field is 

 being damaged, making it inconvenient to use a team and power sprayer. 

 In such case a knapsack sprayer (See page 36) can be used to advantage. 



Paris Green Applied Dry 



Good results have followed a dry application of Paris green. If to 

 be applied in this way mix at the rate of 1 pound of the poison to 10 

 pounds of low grade flour or finely pulverized air-slaked lime. This 

 mixture can be dusted over the beets by using a sack made of coarse cloth 

 or a tin shaker with the bottom perforated with rather small holes. Best 

 results are secured if the dusting is done early in the morning when the 



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