442 
The Progress of the Hessian Fly. 
which have been found efficacious in the United States, mutatis 
mutaridis, and are for the most part simple and easily adopted. 
The first and most obvious of these is to cut the infested corn- 
plants above the second joints by setting the machines high, in 
order that the pupa-cases may be left on the stubble. Imme- 
diately after harvest, the land should be ploughed, the plough 
having a skim-coulter, so as to bury all the stubble. Or, the- 
land may be broad-shared, scarified, or cultivated, and the 
stubble collected carefullv and burnt. Ploughing is by far the 
safer method. Where clovers, sainfoin, or artificial grasses 
have been sown on the corn, the only possible means of preven- 
tion, short of ploughing in everything, " seeds " and all, is to 
brush off the stubble with blunt scythes, or poles, and collect it 
and burn it. Should the infestation be very serious, it would be 
desirable to plough the " seeds " in together with the stubble. 
In districts where destruction had been extensive, farmers 
might combine to sacrifice " seeds " in this way, and to carry 
out other methods that had been useful elsewhere in stamping 
out the insect. In Russia, the stubble is ploughed in where 
seeds have not been sown, and, as Dr. Lindeman observes, 
the farmers naturally object to plough up "seeds" which would 
spoil the course of husbandry. Dr. Lindeman says that on 
a farm in Russia a field of rye was so infested and injured, 
that the plants were rolled down and ploughed in. Burning 
stubble is not practised in Russia ; it is not recommended by 
Dr. Lindeman. 
Late sowing winter, or fall, wheat, that the plants may not 
be above ground until the autumn generation of flies has been 
exhausted, is a most important method of prevention. Though 
on some soils this means a diminution of the crop, and might 
even mean the enforced sowing of spring wheat, it would be 
well worth the sacrifice in very bad cases of infestation. This is 
practised in the United States very frequently, and Di*. Linde- 
man holds that the late sowing of winter corn in Russia 
would be the best means of stopping the spread of the insect. 
He states that he advocated this in Russia in 1880, and that it 
was adopted by many farmers.* 
But with this late sowing of autumn wheat there must be a com- 
plete freedom from self-sown corn-plants in adjacent fields and on 
the outsides of fields. This is also insisted upon by Dr. Linde- 
man, as it is clear that these plants would serve as media for 
carrying on the wiinter generation until the spring. These 
can be destroyed absolutely in ordinary stubbles by ploughing. 
In " seeds " the self-sown corn-plants must be fed off with sheep, 
• Op.cit. 
