WHEAT-BULB FLY. 39 



whilst there was an attacked part on each side where the crop had been 

 removed early and the ground summer-fallowed. Also, in the very 

 useful note given by Mr. E. A. Fitch, we have an account of a twenty- 

 acre field of Tares, which was fed off, and on the part where the land 

 was first folded and ploughed, and therefore longest fallowed, the attack 

 was very bad, but went on over the field with less intensity, until, 

 on the side not fallowed at all, the maggot hardly did any harm 

 (see p. 37). 



All these observations seem to point strongly to the attack on the 

 young sprouting Wheat not being from the fly laying eggs on it, but 

 from maggot in the ground. It seems beyond all probability, or any- 

 thing that we have precedent for, to suppose that in a field of Wheat, 

 of which the whole was sown at the same time and under similar 

 conditions, the jiies would leave or choose portions, almost to marked 

 lines, where the whole crop would serve them equally for food. 



But with the maggot the matter is quite different. If the eggs 

 were laid on the exposed land, or not laid'on the protected land, there 

 (accordingly) would be presence or absence of maggots, and we thus 

 appear to me to reach to the probable explanation of cause of attack. 



The non-appearance of the infestation on the trampled headlands, 

 as observed by several correspondents, points in the same direction. 

 In case of the fly laying her eggs subsequentUj to plowjhiny, there does 

 not appear to be any reason why the attack should be worse here than 

 in the field. But if the eggs, or the maggots, were there, the trampling 

 and compacting the soil might be well believed to lessen their amount. 



Whether the above views are the correct ones remains to be proved, 

 but these alone would explain the peculiarities of the attack, which 

 have long been well known, and would reconcile all the conflicting 

 points. One of the best methods of proving the view^s which occurs at 

 present, would perhaps be ploughing with skim-coulter, attached so as 

 to turn down the uppermost (and probably maggot or egg-infested) 

 surface, and bury it well away beneath the deeper land slice, which 

 would be laid on the top. This might easily be tried first on a small 

 scale, say on an acre or so, where there was likelihood of infestation 

 being found ; and if absence of attack followed in an otherwise infested 

 field, we should have gained most useful information. At present our 

 only really well-founded hope of escaping infestation, in districts where 

 the attack is commonly prevalent, appears to be not sowing Wheat 

 after summer fallow ; but if the maggot proves to be in the ground, 

 then the way would at once be open to prevention of attack by various 

 forms of dressings, or ploughings, or, in some instances, where nature 

 of the soil allowed, by rolling or sheep-treading to compact the soil. 



