PREVENTION. 55 



■we start Fly attack or not, by much use of animal 

 manure, at least where infested Cabbage has grown 

 we are not likely to get rid of the grub from the 

 ground by simply digging in stable or cow-shed 

 manure ; on the other hand, we find chemical 

 dressings have cleared it. We have instances of 

 grub attack not having taken place in an infested 

 district, or having been cleared out where it existed, 

 by the use of gas-lime, or hot lime. The gas-lime 

 was carted on to the land during frost, and presently 

 spread ; and the land on which this was sprinkled 

 escaped attack, whilst on that which was not dressed 

 the crop was lost by maggot. "Where the crop has 

 been cleared by maggot, it has been found that a 

 handful of hot lime mixed with the soil, before dibbling 

 in the new plants, prevented any new attack. Super- 

 phosphate of lime is also recommended in continental 

 practice. 



The Fly needs a suitable material to lay her eggs 

 in, with some instinctive prospect of food for the 

 maggots, and the lime does not present her with 

 either one or the other: the maggots have a poisonous 

 material instead of food added to the soil, and alto- 

 gether the position is made quite an unnatural one for 

 the attack. 



Where a plentiful supply of farm manure is used, 

 we find (with various crops subject to Fly attack) 

 that it answers well to prepare the ground and put the 

 manure in during the previous winter. With Onions 

 it has been found the most successful plan of growing 

 is to work the soil deeply in the autumn or winter, 

 and put a good layer of manure at the bottom of the 

 trench, or work it well into the soil. The surface is 

 laid up rough or ridged for the winter, and when 

 sowing time draws near is levelled. Thus there is no 

 fresh farm manure on the surface, although some 

 fertiliser, such as soot or wood-ashes, lime, &c., 

 is usually strewn on the surface, or otherwise applied, 

 at sowing time. With Carrots it has also been 



