112 Mode of guarding against the Asparagus Fly. 



fly. The only one yet in practice is to cut off all the shoots of 

 the asparagus to the end of May; but where, on account of 

 seed-beds and newly formed beds, this method cannot be em- 

 ployed, the asparagus must be left to its fate." 



After having struggled in vain, for the space of eight years, 

 against the attacks of this fly, and having also applied all sorts 

 of offensively smelling substances with a view to the destruction 

 of the insect, but without success, the thought struck me, that 

 I might, perhaps, sooner attain the end in view, by operating 

 on the insect's sense of sight. For this purpose I set apart a 

 bed of asparagus, which had been sown five years, the two last 

 of which it had suffered severely from the fly. In the beginning 

 of April I stuck in the pine branches close together (which, in 

 winter, had been used as a covering) all along both sides of the 

 rows of asparagus. Their points met close together over the 

 plants, at a height of from 28 in. to 36 in., and formed a thick dark 

 foliage. I had at first but little confidence in the attempt, be- 

 cause I was afraid of finding, as might be supposed, an immense 

 number of the fly under the foliage; but in this I was mistaken. 

 The fly, on the contrary, hastened from the dark shade to broad 

 daylight, and, as long as the plants vegetated under the foliage, 

 no shoots were attacked by it ; but as soon as the tops pene- 

 trated through the covering to the open day, they became in- 

 fested by the fly. If the shoot had already begun to branch 

 out, only the twig that was attacked died; the others vegetated 

 well, and no larvae were found in the stems. It happened, also, 

 that some shoots burst through the sides of the covering, the 

 tops of which, when they had only just begun to branch out, 

 were likewise immediately attacked by the fly, and suffered ex- 

 ceedingly. When I examined the passages of the larvae, I 

 found, to my great satisfaction, that, instead of extending as 

 far down as the surface of the ground, they regularly terminated 

 where the stem began to be woody. 



When the asparagus, therefore, has attained the height of 

 12 or 18 inches, and the stem become woody, it will no longer 

 suffer any material injury from the fly : at least, I found it so 

 from my own experience ; also, that seedlings suffer little from 

 the fly the first year or two, as the shoots then consist of little else 

 than cellular tissue. 



The fly seems to dislike shade and moisture. I never could 

 find any during wet weather, and when the sky was cloudy 

 they were very seldom seen. It is, therefore, very possible, that the 

 fly might be warded off* by planting some kind of early-growing 

 vegetables between the rows of asparagus, as a shade ; such as 

 artichokes or early peas. Unfortunately, I have no longer an 

 opportunity of making more experiments, and, therefore, sincerely 

 pe that others will do so, and communicate the results to the 



