rnJ. Kcrrns cr^ncludod fron the alovo erpcri^nents that derris is much 
more toxic to the \)cetles than rvrrthrun v;hrn used in dust form, and 
that a satisfactory control cf Fhyllodectr vitellinao can ce olDtained 
hy the use' of a derris dust. Under dry-wcathcr conditirns the powder 
aftrr applicpti'^n rctr.in'f^^d sufficient pffcctivr toxicit" to kill or 
to reppl v/anderinc leetles for at least 3 f^-f^ye* 
Fhyl lode eta vulgatissima (l.) 
I ' • ' 
Jensitive to derris dust. — DeBussy et al.'(6l); also Van der 
Laiin ( 2^2 ) in 1936. 
fhyllodecta sp. , "blue and "brf^'^sy "beetles • 
ICearns ( 236 ) in 1935 recormended derris spray and derris duet for 
the control of ingr^ct pestg of "basket willows. The spray should contain 
not less than O.OOU percent of crystalline rotenone, and 1/2 pound wetter 
("best suited for hard waters), per 100 imperial eallons of water, Derris 
dusts should contain not less than -0,15 percent "f crystalline rotencne. 
Dusts pr-^vide a satisfactory control of the adults of the blue and "brassy 
"beotle, Phyllodecta sp, , and the larvae and adults of the l-^rown "beetle. 
The "best results are o"btained v^hen the "beetles ha""'e collected in con- 
sidcra'ble nunl-rrs on the shoots and v^un?; leaves in the early sprint;. At 
othrr ti.-nes of applica.ti'^n dusts do not civ'- satisfactory results. "Derris 
may "be used in connecti-n with ""ordeaxir mixture. 
Phyllotrcta al'bicnica Lee. . a cacla,£;e flea "beetle 
Derris dust (3.05 percent of rot'^none) was very effective in field 
testr- alone and vfhen dilv.tcd with gyosum in th-^ ratios of 00:10 and 70:"^0.- 
Kelsall and Stultz (gU^) in r'37, 
Phyllotrcta atra (F.) 
Fethcrbrid. e an:'. Thonas ( 717 ) in IO35 roportrd en the control of 
flea beetles in secdcc-ds in In^rland. The «;pt'cies of flea beetles found 
attackin..- caboaj^e plants durin.--;; the cdirse of the present investigations 
were the followine: Fhyllotrcta atra (F.), P. cor.so"b'rina (Curt.), P. 
cruciferao (Gcezc) , P. nernoran (L.). P. ni^-rlp's (?.), fT punctulata 
(Karsh), and P. undt;lata Kutsch. In I03I best results a^'tor the -slants 
were up were obtained with a U-->^rrcent-riicotine dust. Poor results wore 
o"ljtained with hepvy derris dust, t'^.r dusted beds be inj: as se.v»jd," attac'red 
as the controls. The dust was a.la" difficult to apply with a rotary blowei 
and injured the plants. In 103^ experi-'^.ents were n?>dc on cauliflowers 
with 3-percent-nicotino duat, ii?;ht and nediu-n d'errig dusts (0.2 p. rcent 
of rotenone) , and other materials. The best control was obtained with a 
li^ht derris dust a-oplied four tiies, the ^lots having/ only three applic- 
ations being nearl,; as .-.-ood. 
In a season when flea beetle dajna:re is vory bad, the following 
procedure was recoanended for caobaire seedbeds? (l) Fre-oare as fine a 
tilth as possible; (2) anply naphthalene or a derris dust about U or 5 ' 
days aftrr the seed is sown; (3) dust vrith a liirht derris dnet as the 
plants are cornin^: throut:h the cro^ind; (U) gubgenuently , dust with a 
