CHRYSANTHEMUM MIDGE. 15 
sidered. The control of the adult stage need not be taken up in experi- 
mental manner, in view of the known fact that such fragile flies can 
easily be controlled by light fumigation with hydrocyanic-acid gas or 
by burning tobacco papers, provided it is done at the correct time. 
The preceding paragraphs clearly point out the advisability of 
determining the practical value of the several premises stated. 
Incidentally such factors must necessarily be solved independently 
of each other, but with the final view of either applying each separately 
when the case so warrants or consolidating such phases as would be 
most practical and consistent with commercial practices. The 
practical conclusions and recommendations that follow were deduced 
from results that are outlined and stated in the following pages. 
EXPERIMENT 1.—CONTROL OF EGGS BY MEANS OF DIPPING INFESTED CUTTINGS. 
Emphasis has been placed on the importance of beginning with 
clean cuttings in the spring. It, therefore, was found advisable to 
test out this point, and, if effective, such practices would be a safe- 
guard to growers whose stock was badly infested as well as growers 
who had received outside material. 
Three lots of six cuttings each were treated by J. L. Dietz as given 
in the following table. After treatment they were planted in sand. 
- The tray, together with the plants, was then protected from further 
attacks by placing it under a close-mesh screen. The plants were 
treated September 26, and observations taken October 5 and 10 
and November 1 are given in Table V. 
TABLE V.—Conitrol of eggs by means of dipping infested cuttings. 
Ex- 
peri- Treatment. Observations and results. 
ment. 
1 | 40 per cent nicotine sulphate (1-500); laundry | Nov. 1: Eggs did not hatch; no new galls devel- 
soap 1 ounce to 1 gallon; tips of cuttings oped; 4 plants well rooted, 2 plants poorly 
dipped. Sept. 26, 1918. rooted. 
Same treatment as above except that entire | Noy. 1: Eggs did not hatch; no new galls devel- 
cuttings were dipped. Sept 26, 19 oped, neither did original galls develop any 
further; 4 plants well rooted, 2 plants poorly 
roote 
Se lee@heck=noltreatment = >> fers rs sn EL): Nov. 1: Eggs hatched; 1 plant had 3 well-devel- 
oped galls present; 3 plants rotted off; 3 plants 
were Well rooted. 
DISCUSSION OF RESULTS. 
Comparing the results of both treated lots with those of the check, 
the results are fairly conclusive. On the treated plants the eggs in 
each case did not hatch, neither did the young galls originally present 
make further progress, whereas, in the case of the check, while only 
one plant showed definite results, it is clear that the galls developed. 
The effect of such treatment on the plants is somewhat inconclu- 
sive due to the rotting off of three plants in the check. In the case 
of the treated plants, four survived in each lot. 
