14 MONTANA EXPERIMENT STATION BULLETIN 442 



PEA WEEVIL (Bruchus pisorum). — This pest was extremely 

 abundant in the Billings area in 1945, and considerable loss of peas 

 resulted. In 1946 it was of minor importance. Examination of past 

 records of its occurrence in Montana, and an extensive survey in 

 1941 led to the conclusion that the State was marginal as far as 

 extensive outbreaks are concerned.' The pea weevil appears to fall 

 in that group of insects which may fluctuate considerably in num- 

 bers from year to year, and, at present, methods of predicting 

 severity of infestation have not been developed. 



ASPARAGUS BEETLE (CHocerus asparagi) . — Montana has 

 been remarkably free from many of the important garden pests 

 which plague truck growers in other parts of the country. Such 

 insects as the Mexican bean beetle and the squash bug do not occur 

 in the State, and others, such as cucumber beetles and the tomato 

 horn worm, are uncommon. 



The asparagus beetle was unreported in Montana until the 

 spring of 1946, when Mr. H. A. Johnson of Poison submitted speci- 

 mens on May 29. A survey of the area on June 6 disclosed a distri- 

 bution involving plantings along the southeast portion of Flathead 

 Lake from a point two miles east of Poison and north to Findley 

 Point. It is possible that the beetle occurs farther north, but the 

 survey extended only to the Point. 



Probably the infestation started from imported crowns plant- 

 ed somewhere within the presently infested area previous to 1946, 

 and there is no neason to believe that the infestation will remain 

 within its present boundaries. 



The asparagus beetle attacks only asparagus as far as is known. 

 It is a European species, first appearing on the east coast about 

 eighty-five years ago. It has spread throughout the East and occurs 

 in some western states. The adult beetle is a pretty insect, about 

 one-eighth of an inch in length. The wing covers are shiny bluish- 

 black marked with cream colored spots, and the thorax is red. The 

 thorax is narrower than the head or the body, giving it a "narrow 

 necked" appearance. 



Adults hibernate during the cold months wherever they can 

 find proper protection, coming out in the spring to deposit their 

 eggs on asparagus growth. The eggs are dull slate-grey, and con- 

 spicuously placed at right angles to the stem. Within a"' week they 

 hatch into small fleshy, grey larvae, which commence immediatelv 

 to feed on the growing t^ps. When fully developed, and about one- 

 third of an inch in length, they drop to the ground to pupate. Adults 

 emerge from the soil in approximately a week to lav eggs for a 

 new generation. They fly readily and' may infest plantings close 



"Mont. Agr. Exp. Sta. Bull. 408, pp. 22-23 and Mont. Ext. Serv. Cir. A-30. 



