206 On the Insects affecting the Turnip Crop, 



beetles from tlieir retreats ; and it is worth considering whether 

 bj early sowing we do not entice a hungry horde from their winter 

 quarters, or from the banks and meadows where they are at first 

 supported ; whereas by not sowing until Midsummer the beetles 

 may in the mean while be starved and drawn off to more favour- 

 able localities, or have fallen a sacrifice to small birds and the 

 casualties of the wet and cold of our spring. Such seasons we 

 know do not agree with the beetles ; and I have observed that 

 when the dew is upon the turnips in the autumn, they keep under 

 the leaves, and appear to be asleep ; and windy weather has a 

 similar effect in rendering them quiescent. The crops being 

 attacked and destroyed in the autumn^ does not altogether militate 

 against good success at Midsummer, especially in forward seasons. 

 Similar objections to the above may be urged against sowing the 

 white turnips with the swedes ; for if the quantity of beetles be 

 small, the swedes may be preserved in consequence of the turnip 

 being their favourite food ; but on the other hand multitudes may 

 sometimes be thus attracted from a distance, which would not 

 otherwise, it m.ay be presumed, have detected the swedes^, from 

 their scent being less perceptible. 



It is now three years since I intimated that ^'some benefit might 

 be derived from destroying those cruciferous plants. Erysimum 

 aUiaria and Cardamine pratensis,""' to which these Alticce are so 

 strongly attached, for they grow in abundance in every hedge and 

 meadow : they appear long before the turnips come up, and 

 attract and give support to the parents of the future swarms that 

 are to sweep away the crops of the farmer." f As these plants 

 often flower at the beginning of April, and produce their leaves at 

 a much earlier period, it is almost certain that they nurse the fly, 

 and are its great resources for food and nourishment in the 

 earliest days of spring; but how to eradicate the Cardamine is 

 for future consideration. The hedge-mustard, and other cruci- 

 ferous plants on banks and road-sides, are quite under our con- 

 trol ; and it is a duty which we owe to our neighbour as well as 

 to ourselves, to keep our fields and hedges clear of charlock and 

 every allied weed of that family, all of which harbour the turnip- 

 beetle. 



Before dismissing this portion of the subject, two or three 

 remarks will be useful. It is certain that manure gives strength 

 to the turnip-plant, but it is doubtful if it will destroy the beetles. 

 Hoeing and rolling may harass and kill many of them ; and as 

 this process promotes the more rapid growth of the plants, it must 

 be attended with no slight advantages. I expect also that if it 



* Cuitis's Brit. Ent., pis. 569 and 179, called sauce alone, or hedge-raus- 

 taid, and common ladies -smock, 

 t Ibid., folio 630. 



