. - 542 - 
Aphis gossypii Glov. (melon aphid); Brevicoryno (A) brr.ssicae L. (cabbagi 
aphid) ; Acyrtho siphon ( iviacrosiphu m) pisi Kalt. (pea aphid) ; Thrips tabac : 
(onion thrips); Diabrotica soror Lee. (western tv/elve- spot ted cucumber 
beetle); and D. trivitatt a Mannh. (western striped cucumber beetle). 
The process of manufacture, the type of dusting machine used, and the 
results of the experiments are described. -For the. control of aphids 
other than Aphi s .juglandicola Kalt. a higher strength of nicotine sul- 
phate than 2 percent is necessary and for Ac yrtho sipho n pisi Kalt, a 
10 percent strength should be carefully applied, this aphid being most 
resistant to nicotine. The material used against the cucumber beetles 
was a 10-percent strength of nicotine sulphate (40-percent) in a car- 
rier of kaolin and lime. Dusts are more effective and cheaper than s ,raj 
ESSIG, E. 0. (2283) 
1921. DUST INSECTICIDES IN CALIFORNIA. Jour. Econ. Ent. 14: 392-394. 
[Abstract in Rev. Appl. Ent. (A) 10: 131. -1922.] 
Black Leaf 40 used as a dust, has proved successful in the treat- 
ment of various aphids at a strength of 5 or 6 percent. Against the 
rosy apple aphid ( Aphi s malifoliae Fitch) dusting was begun as the 
leaf buds opened. A dust containing 6 percent Black Leaf 40 was 
sufficient against melon aphid ( Aphi s goss ypii ) , Nysius ericae Shill. , 
and nymphs of Typhlocyba ( Erythron'eura ) come s Say. Adults of the 
latter were killed by a 10-percent mixture. 
The caterpillars of various Lepidoptera also readily succumb 
to Nicodust treatment, including those of Ma lacosoma spp* (tent 
caterpillars), Fseudohaz is eglanterina Boisd. (brown 'day moth), 
Hypantri a c unea Drury (fall webworm) , and Fyrameis ( Vanessa ) cardui L. 
Lime liberates the volatile nicotine more readily than kaolin 
and is therefore used in preference to the latter as a base for 
nicotine dusts. The addition of dry sulphur also increases the ef- 
ficacy of the dust. 31ack Leaf 40 and sulphur without lime are more 
efficacious than nicotine and lime without sulphur, but the former 
mixture, owing to its weight, is not so easily handled in the dust- 
ing machines. Nicodust and powdered lead arsenate efficiently con- 
trolled caterpillars and flea beetles, especially the latter on 
tomatoes. 
HARTZELL, F. Z. (2284) 
1921. FEAR PSYLLA INVESTIGATIONS DURING 1920. N. Y. State Hort. Soc. 
Proc. 66th Ann. Meeting, pp. 50-57. [Abstract in Rev. Appl. 
Ent. (A) 10: 211. 1922.] 
A spray containing 2 gal. lime-sulphur, 40 lb. hydrated lime 
and 1 pt. Black Leaf 40 per 100 gal. water killed 97.9 percent of 
the nymphs ( Fsylla pyricola Forst). Where 60.1b. of kaolin was 
substituted for lime the foliage was considerably injured. Bor- 
deaux mixture 4-40-100 and nicotine even when used with an ex- 
cess of lime caused serious russeting of the fruit. Dusts composed 
