494 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 9 



at this time, before and during oviposition, helps to reduce the de- 

 structive new generation of larviE. No other natural enemy of like 

 importance was observed at this season. In the early spring, the op- 

 timum conditions for the growth of the fungus arc likely to be found in 

 all the alfalfa. fields on the East Bench of old Lake Bonneville regard- 

 less of the irrigation practice. The ground-frequenting habits of the 

 weevils at this time, the season of mating on the ground under the 

 early low growth of alfalfa, especially expose them to infection by fre- 

 quent contact with the bodies of insects covered with the spores of the 

 fungus. 



Later in the season when the spring rains have ceased, the fungus 

 seems to be restricted to fields which are generously irrigated and have 

 a heavy close stand of alfalfa. One such field was examined on July 

 29 and 28 weevils with a pure growth of Sporotrichiim were picked up in 

 a short time. Such mortality at this late date is of slight importance, 

 however, as this is the time when the over-wintered adults are dying 

 off naturally. Yet it is worthy of note that this field for which a gen- 

 erous water supply Was available and which was therefore lavishly 

 irrigated has never been seriously injured by the weevil; at least so 

 the rancher informed me, and I was inclined to believe him as it was 

 certainly unusual for a Utah farmer to deny injury from the weevil. 

 The fungus was observed in this field in abundance on ^'eptember 10. 

 Other insects killed by the fungus, notabh' Sitorjes sp., were also abun- 

 dant in this field. 



A spontaneous outbreak of the disease occurred among weevils of the 

 new generation in a rearing cage at the laboratory about November 

 17 and caused a high mortality. Many weevils also died of the disease 

 in an outdoor hibernation cage during the fall and early spring. 



The Fungus 



The fungus on Hypera variabilis (posticus) Hbst. was determined as 

 Sporotrichum globuliferum Speg. by Dr. Flora W. Patterson, Mycol- 

 ogist of the Bureau of Plant Industry, U. S. Dept. of Agriculture. 



The fungus is probably distributed over all of the Americas and has 

 been recorded as found on the bodies of insects of several orders. 



The macroscopic appearance of the fungus on weevils varies with 

 the conditions under which the exterior gix)wth of the fungus devel- 

 oped. In a confined dark cage with little or no ventilation, the fungus 

 usually completely envelops the weevils in a loose, fluffy, cottony 

 growth of fungus mycelium in the outer strands of which the scattered 

 balls of spores are developed, the balls being usually separated from 

 each other by an appreciable distance. Weevils partially buried in 

 moist locations in the debris under alfalfa plants in the field also often 



