400 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 14 



Observation on Nicotine Dusts Against The 

 Woolly Apple Aphis 



Prof. P. J. Parrott has reported' nicotine dusts as strikingly ineffective 

 against the woolly apple aphis in his experiments. This is as would be 

 expected but for some reason the writers preliminary tests have shown 

 remarkable susceptibility of this species to nicotine sulphur dusts aver- 

 aging about 1.6% nicotine- and som.ewhat less susceptibility to a dust 

 containing over 2% nicotine with a carrier composed of 90% lime. 

 Although only a few infested trees have been available for this work, 

 repeated applications have given uniformly good results. The writer 

 has had experience in the use of nicotine soap solutions against the woolly 

 aphis but in the preliminar}- dusting experiments here referred to, obtained 

 better results with less effort than previously with the wet applications. 



Using the dusts mentioned above colonies of the aphids were frequent- 

 ly completely eradicated on small trees with dust blown from, a distance 

 of three or four feet with not enough air pressure to disarrange the waxy 

 covering of the insects and with so little dust remaining attached to the 

 wax as to be scarcely noticeable to the naked eye. The difference in the 

 results obtained by Professor Parrott and the writer may be due to the 

 difference in nicotine content of the dusts tested or perhaps to the dusting 

 machine used by the writer being better adapted for the work. The appli- 

 cations here recorded were made with temperatures ranging from 75 to 

 85 degrees but no relation between the temperatures and the results 

 was noted. 



TWO MECHANICAL DEVICES FOR CONTROLLING 

 WESTERN CUCUMBER BEETLES 



By Rov E. Campbell, Assistant Entomologist, and Walter H. Nixon' 

 In the State of California the western twelve-spotted cucum.ber beetle 

 {Diahrotica soror Lee.) known locally as well as somewhat generally as the 

 "Diabrotica," and erroneously as the "green ladybird", causes consider- 

 able dam.ge each year. 



The beetle is a very voracious and universal feeder, the number of its 

 food plants being placed at over five hundred. From a commercial 

 standpoint, the injury is confined mostly to crops such as beans, cucum- 

 ber, alfalfa, beets, p^m^.pkin and melons. The injury of cucurbits is to 

 the stems and leaves of the young plants ; of alfalfa and beets it is to the 



'jour. Econ. Ent. Vol. 14, p. 211. 



^The writers statements of nicotine content refers to the results of analyses of 

 the manufactured dust and not to the amount of nicotine added to the carrier. 

 ^Assistant Superintendent, Trial Grounds, C. C. Morse & Co., San Carlos, Cal. 



