330 
JOURNAL OF ECONOMIC ENTOMOLOGY 
[Vol. 17 
Mr. J. A. Hyslop: Mr. Haseman’s statement in regard to broadcast 
treatment with calcium cyanide destroying the bugs, brought to my 
mind the statement of Mr. Turner, that the broadcasting treatment 
now being used in Georgia, for the weevil, made so extreme a change 
in the biological complex in the cotton fields, that the cotton aphis 
was very much more destructive in the fields treated than those not 
treated. I believe in these new, very extensive treatments that the 
Entomologists are using, that we will do well to consider the changes 
in the complex in relation to other insects than with which we are working. 
The final business of the Association was then transacted and the meet¬ 
ing adjourned. 
NEW DEVELOPMENTS IN ALFALFA WEEVIL ACTIVITY 
AND CONTROL 
By Claude WaIceland, Entomologist , Idaho Agricultural 
Experiment Station 
Investigational work was undertaken by the Idaho Agricultural 
Experiment Station this year to determine why spraying for the control 
of alfalfa weevil (Phytonomus posticus Gyll.) in southwestern Idaho 
had not proven so successful as elsewhere. The situation is of more 
than local interest because it shows the error of assuming that problems 
that have been successfully solved by research workers can be turned 
over to extension workers and forgotten. 
Spraying for the control of this insect has been recommended generally 
as a practice proven by experiments conducted by the U. S. Bureau of 
Entomology (1) (3) and by the Colorado Experiment Station (2). It 
was found that one spray application reduced the injury to such an 
extent that little loss was sustained on the first crop and the second 
crop started growth immediately after the cutting of the first crop. 
This spray is applied at a time designated by Reeves and his co-workers 
as the “turning point of injury” ( Fig. 8). This turning point is 
governed by the relative development of the weevil and its host plant 
and occurs close to the date when the greatest number of larvae are 
emerging, which usually is from one to three weeks before the date of 
cutting of the first crop. In Utah and Colorado the majority of the 
larvae usually emerge from the eggs at a rather definite time, which 
may be designated as the “height of the hatching season.” Under 
conditions there, height of hatching season and turning point of injury- 
are nearly analagous terms when considered in relation to the timing 
of spray applications. 
