BUREAU OF ENTOMOLOGY AND PLANT QUARANTINE 43 
phyid mite Aceria tulipae, 45 laboratory tests were made using this 
mite. Thirty-seven of these tests resulted in transmission of the 
disease. In view of this finding and the possibility of contamination 
of greenhouse tests by this extremely small mite, it is now thought that 
at least some of the earlier transmissions may have resulted from the 
mites rather than the wheat stem maggots, flea beetles, or leaf hoppers. 
This work was conducted in cooperation with the Bureau of Plant 
Industry, Soils, and Agricultural Engineering, and the Kansas Agri- 
cultural Experiment Station. 
Practical Control Measures Sought for Legume Pests 
Excellent kill of exceedingly heavy populations of the potato 
leafhopper on alfalfa in Maryland was obtained at the recommended 
dosage of y 2 pound of methoxychlor in 5 gallons of emulsion spray per 
acre. Comparable tests with 1 to 1% pints of malathion per acre gave 
very effective kill, but the residual effect was inadequate. Chemists 
found no residues of malathion on samples of sprayed alfalfa col- 
lected 7 days after treatment. 
Application on April 4 of 0.27 pound of dieldrin per acre reduced 
meadow spittlebug populations in Maryand by an average of 66 
percent on alfalfa and -89 percent on red clover. The reduction 
persisted through May 23. 
Alfalfa weevil adults were controlled in the early spring in Utah 
with heptachlor at 4 ounces per acre. This insecticide was as effective 
as chlordane at 1.5 pounds or dieldrin at 4 ounces per acre, the dosages 
now recommended. The use of 8, 13, or 26 gallons of spray per acre 
did not influence the kill of adults or the later populations of larvae. 
Chemists found no more than a trace of insecticidal residue on samples 
of hay taken from the heptachlor-treated plots just before harvest. 
Better than 98-percent control of alfalfa weevil larvae was obtained 
with acre dosages of 1 ounce of either heptachlor or dieldrin, 2 ounces 
of aldrin or endrin, or 8 ounces of chlordane. Further information 
on possible harmful residues will be obtained before any of these are 
recommended. 
Heptachlor gave promising results in controlling lygus bug nymphs 
in seed alfalfa in Utah. A 95-percent control for 19 days was 
obtained with 4 ounces per acre applied when the plants were in the 
bud stage. This compared to 98-percent control through the use of the 
recommended treatment of 1.5 pounds of DDT. In the same experi- 
ment endrin and isoclrin at 0.2 pound per acre gave only 82- and 75-per- 
cent control of lygus bugs but gave excellent control of small popula- 
tions of the pea aphid. Initial field tests were made in Utah to 
determine the toxicity to honey bees of several insecticides that are 
effective against alfalfa pests. Their relative toxicity to bees deter- 
mines their utility for application to seed alfalfa in bloom. Four 
ounces of heptachlor, 10 ounces of malathion, or 4 ounces of TEPP 
per acre, applied in water-emulsion sprays in the early morning before 
the bees began visiting the field, killed too man}' bees to justify 
application during the bloom period. An early morning application 
of aldrin at 2 ounces per acre, or an evening application of TEPP 
at 4 ounces per acre was reasonably nontoxic to bees. 
