74 SOME INSECTS INJURIOUS TO TRUCK CROPS. 



impoverished in vitality and the growth thereby seriously retarded. We were 

 troubled with them last year [1905], but not to the same extent, and had them 

 till after hop picking. In the middle of July they were so numerous that the 

 ground was fairly alive with them. They go into the ground in the evening 

 and come out again in the morning, and there has been no spray found to have 

 any effect without killing the plant. 



Substantially the same form of injury was reported during the 

 same year at Agassiz, B. C, by Mr. John "Wilson in a letter to Doctor 

 Fletcher. Writing Sei:)tember 7, 190C, Doctor Fletcher stated that 

 this species had been enormously destructive in British Columbia, 

 one corresiDondent reporting the loss of many thousands of dollars. 

 He estimated his crop as possibly 70 bales, whereas he should have 

 had 250. 



Writing of this species, January 30, 1907, Dr. E. D. Ball, while 

 working in cooperation with the writer, stated that it was by far the 

 most injurious species on sugar beet in Utah. It was found every- 

 where and was apparently the most common species in early spring. 

 It was observed hibernating around the edges of fields, in patches of 

 dead mustard, along ditch banks, and in similar places. Where 

 ditches were covered with patches of roses these seemed to furnish a 

 favorite retreat. These clumps grew to a height of 2 or 3 feet and 

 were very dense, and from them one could see the injury to the beets 

 radiating in every direction, the affected area growing wider and 

 wider as time went on. In early spring this species fed on almost 

 anything that came to hand, but its injury to beets was practically 

 all done at the time the plants were first appearing through the 

 ground or within a few days thereafter. Cases were observed where 

 the rows of young plants could be seen the entire length of the field 

 one day, and two days later scarcely a beet plant could be found, the 

 beetles having eaten the tender stem, causing the tops to fall off and 

 the beets to die. Frequently they attacked beets just as the latter 

 were pushing through the ground. Hundreds of acres had been 

 destroyed in this way, injury varying greatly in different years and 

 in different localities. 



Great damage was done near Logan, Utah, where the hedge mus- 

 tard was overrunning the fields. At Lewiston, Utah, at the northern 

 end of the same valley, injury was also severe, although there was 

 little of the common black mustard. 



The destruction of a crop by this species does not necessarily entail 

 a complete loss, as the growers replant. The late plants, however, 

 are not, as a rule, as good as the earlier ones, and the weeds get such a 

 start that the land is hard to cultivate. After the beets had reached 

 a leaf diameter of 3 or 4 inches no material injury was noticed, 

 although the beetles continued to appear in the fields throughout the 

 season. Beetles were observed July 20, 190G, at Cache Junction, 



