CHRYSANTHEMUM MIDGE. 5 
While it is primarily a greenhouse pest, A. Gibson, in August, 
1915, found it occurring on both greenhouse and outdoor plants at 
Ottawa, Canada. Well-developed galls on the newly unfolded 
leaves were found by the authors, March 26, 1919, on hardy chry- 
santhemums which had been grown out of doors all winter at the 
Arlington Farm, Rosslyn, Va. A careful inspection of the entire 
stock revealed the fact that the insects had wintered over on these 
plants in the immature stages, probably as either larve or pups 
within the galls. Inasmuch as there were many empty galls present 
on the old dead and dried leaves of the previous season’s growth, 
it was evident that this was an infestation of long standing. On 
April 11, many adults were found entangled in webbing spun by 
spiders among the developing new tip growth. These emerged from 
the above mentioned galls. 
The first severe infestation of the midge brought to the attention 
of the Bureau of Entomology was on chrysanthemums in greenhouses 
at Philadelphia, April, 1917. The entire stock was infested, causing 
a total loss to the grower. During the same year other florists 
reported a total loss of their stock of chrysanthemums valued at 
several thousand dollars. Even in the case of a light infestation 
the foliage is practically valueless for commercial purposes, and in 
the case of a heavy infestation the growth is completely arrested. 
(See Pl. I, C.) 
Owing to numerous reports of injury by the chrysanthemum midge 
in the States of Indiana, Illinois, and Michigan, H. F. Dietz con- 
ducted a survey in this territory during the months of November 
and December, 1918, for the purpose of ascertaining the exact amount 
of damage occasioned by this pest. From the data gathered, this 
general locality proved to be one of the centers from which the pest 
was being distributed over the United States. Greenhouses of 33 
florists were visited, including some of the largest growers and dis- 
tributors in this country. It was evident that if serious pests were 
established in this region, it would be only a matter of a year or two 
before such insects would be widely scattered. This is exactly what 
has happened in the case of the chrysanthemum midge. This pest 
was found established in 8 of 33 places visited. 
Serious injury to infested plants was noted. For example, no 
plants of the variety Dr. Enguehard came into flower, on account 
of their dwarfed, knotted, and knarled condition, with the result 
that the new central stem did not form. Moreover, other varieties, 
including Wm. Turner, were attacked just at the time the crown buds 
were “setting,’’ causing these flowers to become distorted. Asaresult, 
the flowers are not borne upright as normal flowers should be. Such 
evidence may be taken as an indication of the presence of the midge, 
even though the galls may not be numerous enough to attract at- 
tention. 
