[FLETCHER] PRESIDENTIAL ADDRESS 13 
AGRICULTURAL TREATMENT. 
A most necessary part of good agriculture which affects entomology, 
and which therefore an entomologist must study, is a comprehension of 
the principles regulating the rotation of crops, by means of which any 
insect attracted to a locality by a certain food-plant being grown there, 
will not have the same food-plant to feed upon the next year. It some- 
times becomes necessary to change the time of planting or reaping crops, 
so as to present it to its insect enemies, at their regular time of appear- 
ing, in a condition in which it cannot be injured, or even to give up the 
cultivation of a crop for a length of time altogether, so as to starve the 
insects out. For the effective application of this latter remedy great care 
must be taken to have all hedges, waste lands and fence corners kept 
clean from weeds. Occasionally, the planting of a small strip of a more 
attractive food-plant round the outside of a field has had the effect of 
drawing off insects from the main crop. It is a common practice with 
some gardeners to plant a few radishes amongst their seedling cauli- 
flowers in order to concentrate the attacks of root maggots; and in the 
same way mustard is planted with turnips in order to attract the flea- 
beetles: as mustard germinates sooner than turnips, the beetles are 
attracted to it, and then destroyed by dusting the plants with Paris green. 
Lately Prof. Howard E. Weed has practised this bait-trap method with 
mustard in order to collect the exceedingly injurious Harlequin plant- 
bug, which destroys cabbages in Mississippi and other southern States. 
When the strip of mustard has attracted the bugs. it is sprayed heavily 
with a strong kerosene emulsion. 
As an instance of keen perception and useful grasp of a subject in 
this line. | will draw your attention to the remedy first suggested by Mr. 
5 
L. O. Howard for the Clover-seed Midge, which every year so materially 
lessens the output of an important crop in Canada. In my report for 
1885 to the Honourable Minister of Agriculture, I stated as follows : 
“Ontario in 1881 produced a crop of clover-seed worth $648,600. Since 
that time the Clover-seed Midge has made its appearance, and its injuries 
have been so considerable that, instead of Canada exporting large quan- 
tities of this valuable seed, our farmers have now to import seed to sow 
their fields.” 1 used every effort to make known widely the following 
treatment, which was adopted in many districts with most satisfactory 
results, and gradually the production of Canadian clover-seed has increasd 
year by year. 
Instead of cutting the first crop of clover at the end of June and 
leaving the second crop for seed im the fall, pasture the first crop until 
the middle or up to the 20th June, or cut it before the latter date, and 
then let the clover grow for the fall crop of seed ; thus the grubs of this 
first brood (the eggs of which were deposited on the growing clover as 
