- 65 - 
Later results by Eckert (124) showing the comparative toxicity of the 
newer insecticides to "bees are presented in the following tahle: 
Tahle 1. - Th e toxic effect of certain chem icals on honeyhees 
LD-50 in 72 hours, 
Chemical, , m icrograms per "bee , 
Benzene hexachloride 0.15 
(90$ gamma isomer) 
Chlordane 1.21 
Aldrin 0.25 
TDB lo.O 
DDT 4.6 (room temp.) 
12.0+ (950 J.) 
Hexaethyl tetraphosphate 0.29 
Parathion 0.0? 
Tetraethyl pyrophosphate 0.75 
Toxaphene 22.0 
Eckert also oh served that chlordane dusts have reduced the field 
force of colonies "by from 50 to 80 percent when applied to alfalfa in 
"bloom. Chlordane in oil (2.5 percent solution) caused the loss of hrood 
and a portion of the hees when applied in hot weather as an oil spray to 
grass in front of 30 colonies. A quick removal of the affected colonies 
prevented much heavier losses. The hees apparently pulled the fumes 
through the hives hy their ventilating operations. 
The walls of a comh room were sprayed with a 5-P©rcent chlordane sus- 
pension in water for the control of ants and one year later enough chlor- 
dane vapor was present in the room to kill hees within 36 hours. — Eckert 
and West (125). 
In lahoratory tests hees in cages were dusted with a pre-determined 
dose of insecticide at 40 pounds pressure. The dust was allowed to settle 
for 30 seconds after which the hees were immediately transferred to other 
cages for ohservation. The toxicity of 10 percent chlordane-40 percent 
sulfur varied greatly with the temperature. At temperatures helow 76 P. 
chlordane was only slightly toxic, the MLD "being 29.95 pounds per acre, 
hut at 86° P. its toxicity increased greatly. — Weaver ( 484 ). 
Chlordane does not repel hees, hut is very toxic to them if applied 
while they are active in the field and remains toxic from 12 to 48 hours 
following its application depending on weather conditions. There is less 
damage to hee populations from chlordane when used as a spray than when 
used in the form of a dust. — Mont. Agr. Expt. Sta. ( 331 ). 
Cephidae 
Cet)hus cinctus Nort. t wheat stem sawfly 
A 5-percent chlordane dust at 20 pounds per acre permitted an aver- 
