792 PRACTICE OF AGRICULTURE. Part III. 



favorable circumstances of soil, climate, culture, and weather, they seldom occur; and 

 therefore all that the cultivator can do is to prepare and manure his land properly, and 

 in the sowing season supply water when the weather is deficient in showers or the soil 

 in humidity. 



4914. The flt/ attacks the turnip when in the seed-leaf, and either totally devours it, 

 or partially eats the leaves and centre-bud, so as to impede the progress of the plants 

 to the second or rough leaves. Whether the eggs of these flies are deposited on the plants 

 or in the soil, does not appear to be ascertained ; in all probability they are attached to 

 the former, as in the gooseberry caterpillar, and most cases of flies and insects which feed 

 on plants. Preparations and mixtures of the seed, as already treated of (4890.), is all 

 that has yet been done in the way of preventive to this evil. 



491.'5. The caterpillar makes its appearance after the plants have produced three or more 

 rough leaves; these they eat through, and either destroy or greatly impede the progress of 

 the plants. There can be little doubt that the eggs of these caterpillars are deposited on 

 the leaves of the plants by a species of moth, as the caterpillar may be detected when not 

 larger in diameter than a hair. As preventives to the moths from fixing on the turnips 

 for a deposit for their eggs, it has been proposed to place vessels with tar in different parts of 

 the field, the smell of which is known to be very offensive to moths and all insects ; by 

 causing a thick offensive smoke to pass over the ground at the time when it is supposed 

 the moths or parent flies were about to commence their operations. To destroy the cater- 

 pillar itself, watering with tobacco water, lime water, strong brine, and laying on ashes, 

 barley awns, &c. have been proposed. 



4.916. The slug and snail attack the plants both above and under ground, and eat both 

 the leaves and roots. Rolling, soot, quick-lime, awns, &c. have been proposed to annoy 

 them; but the only effectual mode is, immediately after the turnips are sown, to strew the 

 ground with cabbage leaves, or leaves of any of the Brassica tribe. On these the slugs 

 will pasture, especially if they be beginning to decay (which produces a sweetness), and 

 may be gathered off" by women or children every morning. By procuring as many 

 cabbage leaves, or handsfull of decaying pea haulm, or any similar vegetable, as will go 

 over a ridge or two, say at the rate of a leaf to every square yard, a whole field may soon 

 be cleared by picking off" the slugs and removing the leaves once in twenty- four hours. 

 This mode we have found most effectual in clearing a whole field of slugs, and it is ex- 

 tensively practised by market and other gardeners. {Encyc. of Gar d. 2275.) 



4917. The mildeiv and blight attack the turnip in different stages of its progress, and 

 always retard its growth. Its effects may be palliated by watering and strewing the leaves 

 with sulphur ; but this will hardly be considered applicable to whole fields. 



49 1 8. The worms which attack the roots, when they commence their ravages at an early 

 period, impede their growth, and ruin or greatly injure the crop. They admit of no 

 remedy or prevention. 



4919. The forked excre^cewces, known as fingers and toes, is considered an alarming dis- 

 ease, and hitherto it can neither be guarded against nor cured. The following account of 

 it is given by William Spence, president of the Holderness Agricultural Society in 1811 j 

 " In some plants, the bulb itself is split into several finger diverging lobes. More fre- 

 quently the bulb is externally tolerably perfect, and the tap-root is the part principally 

 diseased ; being either wholly metamorphosed into a sort of misshapen secondary bulb^ 

 often larger than the real bulb, and closely attached to it, or having excrescences of va- 

 rious shapes, frequently not unlike human toes, (whence the name of the disease,) either 

 springing immediately from its sides, or from the fibrous roots that issue from it. In thisi 

 last case, each fibre often swells into several knobs, so as distantly to resemble the runners 

 and accompanying tubers of a potatoe ; and not seldom one turnip will exhibit a combin- 

 ation of all these different forms of the disease. These distortions manifest themselves at a 

 Very early stage of the turnip's growth ; and plants, scarcely in the rough leaf, will exhi- 

 bit excrescences, which diflfer in nothing else than size from those of the full-grown root. 



4920. The leases discover no unusual appearance, except that in hot weather they become flaccid and 

 droop ; from which symptom, the presence of the disease may be surmised without examining the roots. 

 These continue to grow for some tnonths, but without attaining any considerable size, the excrescences 

 enlarging at the same time. If divided at this period with a knife, both the bulb and the excrescences 

 are found to be perfectly solid, and internally to differ little in appearance from a healthy root, except 

 that they are of a more mealy and less compact consistency, and are interspersed with more numerous 

 and larger sap-vessels. The taste, too, is more acrid ; and, on this account, sheep neglect the diseased 

 plants. Towards the approach of autumn, the roots, in proportion as they are more or less diseased, be- 

 come gangrenous and rot, and are either broken (as frequently happens) by high winds, or gradually dis- 

 solved by the rain. Some, which have been partially diseased, survive the winter; but of the rest, at this 

 period, no other vestige remains than the vacant patches which they occupied at their first appearance. 



4921. Tins disease is not owin^ to the seed, nor to the time of sowing, nor to any quality of the soil, either 

 original or induced by any particular mode of cropping or of tillage ; and Spence adds, that the most at- 

 tentive and unbiassed consideration of the facts has led him to infer that the disease, though not produced 

 by any insect that has yet been discovered, is yet caused by some unobserved species, which either biting 

 the turnip in the earliest stage of its growth, or insinuating its egg into it, infuses at the same time into 

 the wound a liquid which communicates to the sap-vessels a morbid action, causing them to form the ex* 

 crescertces in question. 



