INSECTS INJURIOUS TO MISCELLANEOUS CROPS 247 



injure it. Several species attack rhubarb, but only two or 

 three appear to prefer it to other plants cultivated in this 

 country. Two insects that are specially identified with rhubarb 

 are the rhubarb curculio and the rhubarb flea-beetle. It is also 

 quite subject to the attack of aphides. 



The other insects which infest this plant are general feeders, 

 such as cutworms and some other caterpillars and a few leaf- 

 feeding beetles. 



The Rhubarb Curculio (Lixiis concavns Say.). — Injury by 

 the above-mentioned species is accomplished by the beetles punc- 

 turing the stalks for food, although 

 occasionally they attack the leaves 

 and seed stalks. This causes the 

 plant to exude juice copiously 

 which, drying, forms clear, tear- 

 like drops (fig. 161). Eggs are 

 often deposited in the stems, but the 

 leaves do not develop, doubtless 

 owing to the moisture caused by the 

 beetles' punctures. The larvae breed 

 exclusively in weeds, such ^as dock 

 (Rumex), and occasionally in sun- 

 flower (Helianthus). 



The insect under discussion is a 

 large, rusty-coated curculio or 

 snout-beetle, measuring from the 

 tip of its long proboscis about three- 

 fourths of an inch, and being of the 

 form shown in figure 162, a. 



Remedies. — The use of poisons 

 on rhubarb during its growing 

 season is out of the question, but the beetles are so conspicu- 

 ous that they can readily be seen on the leaves, and as they are 

 sluggish there is no difficulty in capturing them. They should 



Fig. 161.— Section of rhubarb stalk 

 showing injury by rhubarb curculio. 

 (Author, U. S. Dept. Agr.) 



