October, '16] rockwood: sporotkichum enemy of alfalfa weevil 499 



with this fungus obtained from Elaterid larvse from Hagerstown, Md., 

 through the courtesy of Mr. J. A. Hyslop of the U. S. Bureau of En- 

 tomology, showed less than 50 per cent mortality from this fungus 

 after nearly three months' exposure to the fungus under conditions 

 exactly similar to those of the Sporotrichum experiments. Moreover, 

 it took almost a month to kill the first two weevils by means of this 

 fungus. 



Conclusion 



The entomogenous fungus, Sporotrichum glohuliferum Speg., de- 

 velops spontaneously as an infectious disease of the alfalfa weevil, 

 Hypera variabilis (posticus) on the bench lands of the Salt Lake Valley 

 in the early spring. Infection experiments show the weevil to be very 

 susceptible to fungus infection at this season, a complete mortality 

 from the fungus being secured in breeding cages in usually two weeks' 

 time. The ground-frequenting habits of the alfalfa weevil at this 

 season render it particularly liable to infection from contact with 

 fungus-covered insects. 



The new generation of weevils is less susceptible to the fungus during 

 the periods of aestivation and hibernation in the summer and fall. 

 Moreover favorable conditions for the growth and spread of the fungus 

 are unlikelj^ to occur in Utah at this time. 



The period of greatest mortality from the fungus disease, coinciding 

 as it does with a period of great potential injury from the pest, namely, 

 the oviposition period, makes the fungus worthy of record as a natural 

 enemy of the alfalfa weevil. 



H. S. Smith: Does the fungous disease attack only the adult 

 weevils? 



L. P. Rockw^ood: The larvae and pupae are also attacked but 

 because they are usually on the leaves and tops and not on the damp 

 ground they seldom become infected. 



Dr. E. G. Titus: There are about 30 hosts attacked by this 

 fungus, but in no case has it been noticed to be of economic importance 

 though under observation since 1910. 



H. S. Smith : There is a fungus which works very effectively on the 

 alfalfa weevil in Italy, attacking the larvae. 



L. P. Rockwood: Sporotrichum is very widely distributed and is 

 of more importance than it is usually credited with. 



Chairman H. J. Quayle: The next paper by Mr. Asa Maxson 

 will be read by the secretary. 



