On the Insects affecting the Turnip Crop. 



199 



On the first indication of spring", if tlie weather prove fine, 

 warmed by the sun and cheered by his rays, they arouse from 

 their slumbers, and permanently leave their winter quarters for 

 sunny situations, where they may be seen sitting; on walls in 

 considerable numbers, or sunning themselves on dry banks and 

 on clods of earth, protected from the wind : they have been ob- 

 served in gardens on turnips and cabbage- plants as early as 

 March, and in April on the crops in the fields, but May and 

 June appear to be the more usual periods of their first and most 

 fatal attacks. The autumnal crops have been occasionally de- 

 stroyed by them,* and in one instance I have seen recorded, as 

 late as the middle of September. They may be said to be 

 abundant from May to October amongst the grass, and in all 

 fields, whether of wheat, oats, or barley : a friend of mine ob- 

 served myriads on turnips in Surrey, on the 2nd of September, but 

 they all disappeared in two or three days ; and both sexes were 

 common on the white turnips in Dorsetshire last October. 



It seems that the taste of the turnip-beetle is far less fastidious 

 than is generally imagined. This might be fairly inferred from 

 its abounding in situations where the turnip does not grow : there 

 can be little doubt, however, that it prefers those plants which are 

 termed cruciferous, from the shape of their flowers, of which cab- 

 bages and turnips are examples ; of these the leaves of the horse- 

 radish, the common turnip, and the radish are its favourite food, 

 but cabbages, cauliflowers, colewort, watercresses, ladies'-smocks, 

 and hedge-mustard, called jack-by-the-hedge, are often attacked ; 

 the charlock or wild mustard is also sometimes covered with them 

 at the end of April, and in May the leaves will be seen pierced with 

 holes, but as soon as the turnips come up they desert other allied 

 plants. Mr. Berry has recorded a remarkable exception, for he 

 says that after consuming the cabbage-plants, the flies f attacked 

 and destroyed the young hops, which belong to a very different 

 tribe of plants. Kollar also states, that both summer and winter 

 turnips left for seed suffer in warm and dry weather, from the 

 attacks of the fly injuring the flowers, so as to spoil the produce 

 of the seed. 



The next subject to be considered is a remedy against the 

 attacks of the turnip-beetle, which in some years must cause 

 losses amounting to an enormous sum of money, for so long back 

 as 1786 Mr. Young stated that the turnip-crop destroyed in De- 

 vonshire alone was valued at 100,000/. Now with regard to the 

 eggs, we see that they are laid on the under side of the rough leaf, 

 where they are pretty well secured from rain, and also protected 



* In 1826 a crop was destroyed at Knutsford after the 21st of August, 

 t Might not these have been the Altica co/iclnna, or some allied species ? 



VOL. II. P 



