- 22 - 
Sulfur was nuch ■■lor? .--r'fecti^ o than talc a<^ a diluent for cuTjo-mot powder 
in the cor.trol of this insect. 
Chaetocnr^ma g.ridula (Gyll,)^ a fl?a hopprr 
Rir'per ( 326 ) in I936 r^portnd that derris du?!t gave good results 
in prplirainary trials wh^n applied under a long canopy attached to a 
"Bepji" duster, 
Chae to enema sp. 
Sef^ Hampp ( l7^ ) und.-r Alt lea ^p, ,on page 19. 
Chalc;ous dorsalip Th\ijTib,, the locust leaf miner 
Poos ( 320 ) ir- 19^0 reportrd th^ results of tof^ts of a derris dust 
(0.75 percent of rotenene) C, dor^elis attacking soj''Deans. The grov;er 
aa.'.e a hea'^'y application of the dust ^ and an examination of the area 5 
days 1-ter ir_dic.^ti":d that a very largf- pc- rcf^ntaf- of the adult "beetles 
had either 'he-m killed or driven p.vay. T'hc plrr.ts had made a renarkrtl" 
rr-covfry and were rapidly growing out of the injury. The adults showr-d 
no tendency later to deposit -ggs on the plants, even on thos" not treat-d, 
Chrysochus cobaltinu?; Lee, a Dlu? :Tiilkvreed "be^-tle 
L. G. Snith (^UI-l) in I-3Q eu^.^csted a rotenon--^ dust fo- thr control 
of thip "beetle on peach trees or oth-: r economic plants. 
Chryso^iela populi L, 
Kearns ( 237) in 193^ reported on the control of Melyisona populi 
(L.) ( Chrysonela populi L,) a pest of "basket vrillows in Sngland, Toxicity 
tests in the lahoratory showed that the "beetle is rcndily killed "by a wash 
containing not less than 0.0025 percent of crystalline rotenone. The 
larvae, particularly when fully ga?9vrn, vrc-re not so readily killed "by a 
derris war-h, pnd the application of lead arsenate to the foliage pro-i^'ed 
to D-- a more certain method of controlling them. The ii-.fested "bed wao 
sprayed on Jime 27, 19!'''^, with a combined wash consisting of derris root, 
U pounds of lead arsenate powder, and a proprietary wett-^r ?dded to 100 
gallon" of vrater, the concentration of the wetter "being ad.insted so that 
a. satisfactory deposit of the lead arsenate was o"btainrd on the foliage. 
The wr,c:h killed "by contact action, considera"ble num"berp of "beetles, and 
of fhosc that escaped many more vf-re killed "by t -^e arsenate, Kan;;' of the 
larvae collected a week after the spra."ing died, ' presuma"bly by eating the 
arsenate on the foliag'-, 
Chr.-.-!^o':i.el a sn^p., willow leaf beetles 
Hamilton ( 172 ) in 1937 report-'d that villow le^f beetles (lijV; "^r*- 
Chry.omela "pp.) on blpc'-: willovr trees were well controll'^d by a rspray of 
h pounds of derris or cube powder {h% of rotenone) <^:ic'. k pounds of rosin- 
residue emulsion p^r 100 gallons of water. The spr?i pcts as a repellent 
and contact poison pnC. g.-^^-e good control of l-^rvre. 
