18 REPORTS OF OBSEKVATIONS AND EXPERIMENTS. 



SUGAR-BEET INSECTS. 



Tanymecus confertus as a Sugar-beet Enemy. — Early in the season 

 information reached me of considerable injury to young sugar beets at 

 Ames, this State. With the report were inclosed specimens of the beetle 

 known by the above name. A visit to the infested fields a few days 

 later resulted in confirming what had been claimed by my informant, 

 viz, that this insect was present in large numbers upon a certain field 

 of about twelve acres in extent, the greater portion of which had been 

 completely defoliated. Investigation convinced me that the insect, 

 although quite a general feeder, was more partial to several of the 

 weeds growing in the field with the beets and only attacked the latter 

 when the others had been devoured. Chief among the weeds thus 

 attacked was the common cocklebur (Xanthium strumarium). Such 

 other weeds as Chenopodium alba and Polygonum sp. were also eaten. 



At the time of my visit the iusects were mating, and as the cockle- 

 bur appeared to be their first choice as a food plant, it was surmised 

 that that was the plant which naturally attracted the insect in such 

 large numbers, and that the beet was only attacked after the other 

 had been exhausted. Further investigations revealed the fact that 

 last year, and in all probability for several previous years, the same 

 field and several of the adjoining tracts of land had been allowed to 

 giow up with cockleburs. This leads me to conclude that the insect 

 had bred upon or within this plant in such numbers as to become a 

 pest the present year when most of the weeds upon which they fed 

 through choice had been destroyed. Later the insects dispersed and 

 nothing further has been heard of them as a beet enemy. 



Numbers of the beetle were carried home with me and kept confined 

 in a fruit jar with several plants as food. In all instances the cockle- 

 bur was totally destroyed before the others were attacked. 



Eggs were laid by the insects indiscriminately upon the sides and 

 bottom of the jar, as well as upon the vegetation placed in the jar for 

 food. These, however, did not hatch, as they were evidently abnor- 

 mally placed. Here would have been a splendid opportunity of ascer- 

 taining something of the life-history, had I been provided with breed- 

 ing facilities for rearing and studying its various stages. My limited 

 room here prevented such a study and the opportunity was lost to me 

 for this year at least. 



Where the insects attacked the young beets a sprinkling with Lon- 

 don purple was said to. be effective in checking their injury, but whether 

 by killing or driving the insects awaj was not reported. 



The Juniper Baric-borer. — An insect that is of special interest to us 

 in this part of the country where but few evergreens grow naturally, is 

 the one known as the juniper bark-borer (Phloeosinus dentatus) on account 

 of its usual mode of attack upon our red cedar (Juniperus rirginiana). 

 During the year this insect was called to my attention by Mr. E. Harvey, 

 of St. Paul, through the secretary of the State board of agriculture. It 



