662 



ALLIACEOUS ESCULENTS. 



state. When a crop has been attacked by insects, but little can be done ; 

 but when an attack is anticipated, it may be prevented by watering the 

 ground with some fetid liquid, such as putrid urine, or thin putrid liquid 

 manure, which by its offensive smell will deter the parent insect from depo- 

 siting its eggs in the plant, and at the same time invigorate the plant, and 

 prepare it to resist theii- attacks. 



1470. The onion fly ^ Anthomyia ceparum Meigen, a dipterous insect, not 

 unlike the common house-fly, is the most common insect which attacks the 

 onion, the leek, and the shallot, and as it frequently occasions very serious 

 losses, the following details respecting it by Mr. Westwood may be useful. 

 During the summer months, and especially in June and July, the 

 cultivator of onions is annoyed by perceiving that, here and there, in 

 various parts of his crops, the plants appear to be in a dying state, and the 

 leaves fallen on the ground. At first, this is observed in plants which are 

 only just above the surface of the soil, and which are not above the thick- 

 ness of a straw. These soon die, and then others, of a larger size, are 

 observed to decay in a similar manner ; this continues until the middle of 

 July, and even until the onions are full-grown; at which time they have 

 occasionally sufiicient strength to survive the injury, with the decay of a 

 portion only of their outer layer or root, the centre part remaining sound. 

 In this manner whole beds are destroyed ; and it seems to be of little use to 

 sow again, as the fresh-sown plants fare no better. In light soils especially, 

 the attacks of this insect are occasionally very annoying to the gardener. 

 On stripping off the coats of the young onions which show evident signs of 

 decay, it is at once perceived that it is owing to the attack of a small grub, 

 destitute of legs, upon the vital parts of the bulb or stem of the plants, that 

 its destruction is occasioned. On pulling up a very young onion, its interior 

 is found to be completely devoured by a single grub at its very heart ; but, 

 in plants of larger growth, at least half a dozen of these grubs have been 

 counted, varying considerably in size. In the summer season, these grubs 

 are about a fortnight in arriving at their full gi'owth. They generally con- 

 sume the entire of the interior of the onion, the outside skin of which is 

 alone left dry and entire, serving as a place in wliich they undergo their 

 transformations, without forming any cocoon. In about another fortnight 

 the perfect fly makes its appearance, the time varying according to the season, 

 from ten to twenty days. (G. M. 1837, p. 242.) To prevent the attacks 

 of this insect, it has been recommended to sow after strawberries that have 

 occupied the soil for four or five years, or to strew the surface of the soil 

 with charcoal cinders, such as may be obtained from a wood where charcoal 

 has been made ; or to transplant in preference to sowing, dipping the roots 

 or the bulbs in a puddle consisting of three parts of earth, and one of soot. 

 The most effective mode with a sown crop, we believe to be that first men- 

 tioned, viz., to water with any fetid liquid, such as stale soap-suds mixed 

 with a little stale tobacco-water, from the middle of May till the beginning 

 of July. (G. M. 1841, p. 88.) 



1471. Gathering the crop. When the necks shrink and the leaves decay, 

 pull or dig up the bulbs ; spread them on dry ground, in the full sun, to dry 

 and harden completely, turning them every two or three days, and in a 

 week or fortnight they will be ready to house. Clear ofi^ the grossest part 

 of the leaves, stalks, and fibres ; then spread out the bulbs m an airy loft or 

 cool dry cellar, in which they should be turned over occasionally, and those 



