- 5^ - . 
Phaedon sp. ... 
Korff and Bonins ( 2^9) in 1133 stated that a spray containing 0.5 
percent ?f Pclvrsol (a dcrris? preparation) killed 100 nercent of the iDoetloa 
of Phaedon ^p. in 12 h'-^uris. 
Phyl lode eta Tjtellinp.e (L,), a "^irappy willovr 'bpctle 
A very high kill of willow 'oeptles wa,s o^btained with a derris Au?t 
of knovm rotenc.;c c^ntF'nt.. In dry weather the dust acted as an efficient 
repellent for several days. — A^Tricultural and Horticultural Research Station 
of" the University of Bristol (5U) in IQ33. 
Hutchinson and Kearns ( 210 ) in 1935 reported en th'^ eff ecti^'eness 
of derris dust for the control of the tras^jy willow "beetle in Snsland. A 
proprietary dust, consisting of ground derris root and a carrier, with a 
crystalline rotenone content of O.IS -r.rrcent (ether-extraction method) was 
used. The material was a fine dust and easily distribut^i^d "by means of a 
iliapcara tyj^e of hand "blower, A total of UU9 beetles were collected frora 
a willow "bed, and liatches of ^0 were lightly shaken in Petri dishes with 
a snaJl ouantdty of the derris dust. Imnediately after this treatinent they 
were placed in clean dishes. The following dsi.y ^E percent vrore der^d. This 
experiment shovred that the du.st was highly toric to the "beetles.^ provided 
it ca^e into inti'ciate contact vn.th thr-m. 
As a result of the a'bove experinent further otservations were car- 
ried- 'ut on a "bed of Salix all' a vitellina , A ijlock of 35 stools infested 
with' "beetles, were dusted on Kia.y 3^ ^-J^^^- '^^ ^^^ following day the. stools and 
soil wore examined. The dust had settled on the "bark of the stools and on 
the soil ■ surf -'•cc, but very, little vras evident on the foliage. A total of 
751 beetles WGrp^co^^nted on the .soil surface at the base of the stools, and 
only 3 livinf^ beetles were present on the plants. No dead beetles were 
observed on an adjoinif.r; untreated block of 25 stools on which U50- beetles 
WF.re counted. 
In a seonnd erperinont designed to determine the duration of effec- 
tive toxicity, a stool and its shoots and adjacent soil were lif::htly 
dusted, then covered with muslin to form an insect caf^e, and 12S beetles 
were introduced. The followin;-- day all the beetles were dead. On the same 
stool, 3 da.ys after the dust a- ;C'licati^'n, ?, second batch of 150 booties was 
added to the ca^'e, and of these 127 vrerr dead on the following; day. 
The failure of pyrethrun dust to control the "beetles had suggested 
that the result was due to the poor a'fJiesion of the carrier, kaolinj to 
the insects. An exr^eriment was, therefore, carried out using kaolin mix^^d 
with the finely ([ground dcrris root, to ascertain whethor the efficiency of 
the derris wfi.s affected. In order to compare the results with thoj^ obtained 
with the proT^rietary dust, the kaolin was mixed with the derris root in 
proportions to r{iv(^ the same content of crystallino: rotrnone. The results 
obtained from this expcri^ient showed tliat the kaolin preparation gave a 100- 
pcrcent kill of the beetles, despito its poor ariJiesion, and the results from 
its use were similar to thogs obtained with the proprietary dust, Hutchinson 
