LS 
THE ROSE MIDGE. Ff 
ducing a full crop of flowers. These houses were again carefully 
examined on June 19, and no injury was to be found on any of the 
plants which had been infested so severely during the fall of 1916. 
Moreover, the owner reported that up to June 19 more than twice as 
many blooms had been cut as during the entire previous year. 
The rapid elimination of this pest was due no doubt to two causes, 
(1) nightly fumigation, which killed off the adults before egg-laying 
took place, and (2) the application of tobacco dust, which prevented 
the larvae from entering the soil. Moreover, the tobacco dust served 
a dual purpose, since it prevented the larvee from entering hibernat- 
ing quarters and at the same time fertilized the soil. 
METHODS OF CONTROL. 
It is evident from the experiment described above that a severe 
infestation of the rose midge can be controlled, if not entirely elimi- 
nated, in a comparatively brief period by the careful application of 
tobacco dust on the soil and by persistent nightly fumigation with 
tobacco, in the form of stems, nicotine papers, or one of the volatile 
nicotine preparations.+ 
Where earth walks are present, 1t 1s advisable to spray the walks 
also with a 5 or 10 per cent kerosene emulsion.? 
In the case of light infestations, the midge can be controlled by 
systematic nightly fumigations with tobacco fumes, which should 
be continued until all adults disappear; or by a careful application, 
at the proper season, of tobacco dust. Inasmuch as the broods prob- 
ably overlap during the summer, there is a possibility that frequent 
syringing of the plants would cause much of the dust to wash down 
into the soil before all larvee matured; hence there is a chance that 
some would fall on and enter earth where the dust had lost its 
effectiveness. It would seem, therefore, that the most opportune time 
to apply the dust, if not accompanied with nightly fumigation, is 
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1 Although tobacco stems have been used in greenhouses from time immemorial they are 
being replaced rapidly by nicotine paper and the volatile nicotine extract, owing to the 
fact that the nicotine content of the stems is so variable. Tobacco stems in the proper 
condition (those which have not been allowed to become wet and dry out) will yield good 
results. As there is no satisfactory and easy method by which the florist can determine 
accurately the nicotine content of tobacco stems, however, it will probably be a saving 
of time and money to use the nicotine papers or the volatile nicotine extracts, in which 
ease the directions on the label of the container should be followed. 
2 Kerosene emulsion (stock solution, 66 per cent oil) is made after the following 
formula : 
Kerosene (coal oil, lamp oil) ~____________________u__ gallons__ 2 
Soap (fish-oil or laundry) (or 1 quart soft soap) _—-_______pound__ 4 
VIVES {CSCCIEL EN) eta ag AS eg Oe i gallon__ 1 
First dissolve the soap in boiling water, then remove the vessel from the fire and 
immediately add the kerosene, thoroughly agitating the mixture until a creamy solution 
results. The stock solution may be more conveniently made by pouring the mixture into 
the tank of a spray pump and pumping the liquid through the nozzle back into the tank 
‘for five minutes. A 10 per cent solution can be made by adding to each gallon of the 
stock solution about 5% gallons of water. In some regions the water is “hard,” and in 
such cases it should be broken with a little lye, or rain water should be used. 
