Circular No. 23. July, 1909 



MASSACHUSETTS AGRICULTURAL EXPERIMENT STATION. 



AMHERST. 



A PARASITE OF THE ASPARAGUS BEETLE. 

 By H. T. Fernald, Ph. D. 



The injury to asparagus plants caused by the asparagus beetle 

 [Crioceris asparagi Linn) is fully appreciated by those who raise this 

 crop for market. 



Little protection from this pest has been obtained by the attacks 

 of enemies, and spraying, the use of trap plants and permitting 

 fowls to run in the beds have been the usual methods of control. 



No parasite has been reported as attacking the asparagus beetle, 

 but on the second of June of the present year a tiny four-winged fly 

 was observed by the writer at Amherst, passing everywhere over the 

 plants and carefully examining the eggs of the beetle, which were 

 then abundant on the stalks of the plant. 



The fly appeared to be in no hurry, but wandered up and down 

 the stalks and their branches, examining the eggs of the beetle which 

 it found, and seemed indeed to be rather stupid, often entirely pass- 

 ing eggs no farther away than the length of its body, without giving 

 them the slightest attention. Occasionally an egg would receive a care- 

 ful examination, and one in about every eight of these was apparently 

 considered satisfactory. In such cases the parasite crawled out on 

 the upper side of the egg as it projected from the stem of the plant, 

 the egg being none too long to accommodate the insect. Then 

 heading outward, it gradually bent the end of its abdomen down- 

 ward and slowly pushed its ovipositor into the egg of the asparagus 

 beetle. After a few moments it withdrew the ovipositor and resumed 

 its travels over the plant. This process was observed several times 

 under a lens, the insects not being easily frightened if the movements 

 of the observer were slow, and shadows cast having no effect upon 

 their actions. 



A specimen captured at this time was sent to the Department of 

 Agriculture at Washington, where, through the kindness of Dr. L. O. 



