-7— 
treatment for the control of the mites, including this -species, which cause 
curly-leaf disease of grapes in Germany. 
•Eriophyes sheldoni E^ing '' 
Boyce and Maxwell (13) in 1938 reported that oil sprays, either alone 
or with rotenone-bearing materials, gave promising results for the control of 
the citrus "bud mite -in California.' 
Phyllocoptes oleivorus (Ashm.), the citrus rust- mite 
Winston ( l70 ) in 1936 reviewed information on Derrisol for the benefit 
of Florida citrus growers. ' If a grower who is spraying with lime-sulfur 
solution for rust mites should find.' any aiohids* nresent , an addition of 
Derrisol 1:800 will enable him to control this pest with one spraying. 
Lenfest 1 91) in 1926 x^rote that lime— sulfur mixed with Derrisol will kill 
the rust mites, as well as the aphids, on citrus. 
Phyllocoptes viti cuius Pant. 
P. vitis Nal. 
Stellwaeg ( 141 ) in 1938 recommended a pyrethrum derris spray as a spring 
treatment for the control of these two sp-ecies. 
Gamasidae 
Dermanyssus gallinae (Deg.), the chicken mite 
Mclndoo, Sievers, end Abbott (94) in 1919 reported that when derris r>owder 
was freely dusted over chicken mites confined in jars all were killed within 
24 hours, but when used under practical conditions in a badly infested chicken 
house not all the mites were killed. 
Davidson (50) in 1924 reported the results of tests ^ith derris powder 
and derris extract against the chicken mite. The 'composition of these materials 
was not known. Four infested chicken houses inhabited 'by the common chicken 
red mite were dusted with the finely ground powder- of derris roots. Undiluted 
dust was efficient in one house- and temporarily so in another. In a third 
house a 75-percent dust was only moderately efficient; in a fourth test a 
50-percent dust 'was inefficient. Flour- "as used'es a diluent. David.son con- 
cluded that derris pov/der is a remedy of value, but aroparently t^o or more 
applications are necessary and it' loses its efficiency if diluted more than 
25 percent. It acts on larvae and adult mites by stupefying them, the 
individuals dropping to the ground and dying after 2 or 3, days. The material 
is rather unpleasant to apply. A commercial extract of derris, 16 percent, 
diluted 1:1,000 and 1:500, <-'ith the' addition of whale-oil soap, applied at the 
rate of 4 pounds per 100 gallons, was inefficient. 
Schmitt ( 134 ) in 1930 reported -that dustins with dry powder of the finely 
pulverized root of De rris elliptica was effective against chicken mites. 
