82 
JOURNAL OF ECONOMIC ENTOMOLOGY 
[Vol. 11 
POISONED BAIT FOR THE ONION MAGGOT 
By Neale F. Howard, Madison , Wis.; Specialist, Truck Crop Insect Investigations, 
Bureau of Entomology 1 
During the past two years many inquiries have been made concern¬ 
ing the poisoned bait spray as a remedy against the onion maggot, 
Hylemyia antiqua Meigen 2 (. Pegomyia ( Phorbia) ceparum, P. cepetorum). 
The writer therefore thought it advisable to give at this time a brief 
summary of the work performed along this line in 1915 and 1916. 
The poisoned bait as a control for the onion fly was tested in an ex¬ 
perimental way at the Wisconsin Agricultural Experiment Station in 
1913, under the direction of Professor J. G. Sanders. The results ob¬ 
tained in this preliminary work at Racine, Wis., by Dr. H. H. P. 
Severin were promising. 
In 1914 growers from different parts of the state reported favorable 
results from the use of the spray to Professor Sanders. The infestation 
that year was lighter than in most years, however. In 1915 the writer 
was stationed at Green Bay, Wis., for five months to investigate the 
remedy, working for the Bureau of Entomology under the direction of 
Professor Sanders and Dr. Chittenden. In 1916 the writer returned 
to Green Bay for six weeks to repeat the trial, under the direction of 
the Bureau of Entomology. 3 
In 1915 the poisoned bait was applied to seven acres of onions on 
one farm, where the writer made his headquarters, and to a slightly 
smaller acreage on four neighboring farms. Applications were made 
with a small compressed air sprayer, altered to give a coarse spray 
(PI. 3, fig. 1). The operator walked up and down the fields, about every 
15 or 18 feet, and released a quantity of spray every four paces. In 
this manner about three gallons were applied to the seven acres on the 
average of twice a week, weather permitting, as soon as the onions 
came up until the latter part of June. In the latter part of May the 
amount of spray applied was doubled. The bait was mixed according 
to the Sanders formula, as follows: 5 grams (about 1/6 ounce) of sodium 
arsenite, dissolved in boiling water; one-half pint of molasses; one 
gallon of water. 
1 Published with the permission of the Chief of the Bureau of Entomology. 
2 Stein, in “Katalog der Palsearktischen Dipteren,” Vol. 3, places ceparum Meigen 
(1830) and cepetorum Meade (1883) in synonymy with Hylemyia antigua Meigen 
(1826). This fact, together with the practice of European entomologists of desig¬ 
nating the onion fly by the latter name, makes it advisable, in the writer’s opinion, 
to adopt it in the United States. 
3 The writer desires to acknowledge the cooperation of the Department of Economic 
Entomology, University of Wisconsin, and of the firm of Smith Brothers, Green Bay, 
Wisconsin. 
