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Seven other psyllids have been controlled with nicotine, but these 
species are not economically important. 
Leaf hoppers (Cioadellidae) 
Pota to le af hoppe r, — This insect, Emp oasca fabae (Harr.), is also known 
as the apple leaf hopper or bean leaf hopper and as the potato jassid. It has 
been treated with nicotine sinco 1908 in the United States and Canada, In 
most instances nicotine sulfate as either spray or dust v/as recommended as a 
satisfactory control, but in a few instances it was inefficient or was not 
so good as bordeaux mixture, which acted as a repellent. 
Grap e leafhoppers »— Those leafhoppers, Erythroneura comes (Say) and 
related forms, woro' treated with nicotine in the United States and Canada, 
In 1828 tobacco juice was only partially effective and a tobacco fumiga- 
tion tent on wheels to go over the grapevine trellis v/as recommended as 
effective, but "was soon discarded as impracticable in vineyards, A more 
serious attempt to control these leafhoppers was begun in 1910. The nymphs 
are easily killed with nicotine, but in order to control the adults the 
dosages must be very strong. Black Leaf 40 with scap, bordeaux mixture, 
or other substances added to the sprays were used. Nicotine dusts, if 
unusually strong (7,5 or 10 percent), were generally efficient. 
Rose leafhopper.- — This jassid, Typhi ocyba rosae (L. ), v/as treated 
in the T^TFedY S'-lJa : Ee~s7~"Sweden, Switzerland, Canada, and Czechoslovakia, 
It v/as controlled by using nicotine with coap, Black Leaf 40, and nicotine 
dust. 
Other leafhoppers,— About two dozen 'other leafhoppers have been 
oontrolled with nicotine. The most important of these appears to have 
been the v.hibe apple leafhoppor (Typ hi ocyba pomaria McAtee), 
Mealybugs, Scale Insects, and Coccids (Coccidae) 
Citrus mealybug,— This coccid, Pseudococcu s citri (Risso), has been 
treated with nicotine ' s ince 1911 in the United States, Uganda, Grenada, 
Russia, Bermuda, and the Philippine Islands, Tobacco dust was inefficient 
and tobacco extract gave indifferent results. Black Leaf 40 and nicotine 
were usually effective, but other control methods were available. 
San Jos e scale. --This scale insect, Aspidiotus perniciosus Comst,, 
has been treated with nicotine since 1901 induce n's land, the United States, 
India, and Hungary, Nicotine with soap, lime-sujfur, or an oil was usually 
effective against the immature scales. 
Oys ter s hell jscale, — Nicotine sulfate with soap or lime-sulfur has 
been used succes'sfiTlly"" since 1916 against the young of the oystershell scale 
(Lepl dosaphes ulmi (L.)) in the United States and Canada 
Other coccids, — About 42 other species of coccids were tested with 
nicotine, and it was found effective against all but 4, The best spray or 
dipping solution was kerosene emulsion containing nicotine. 
