138 DISEASES OF CROPS. 



Prevention. — Previously infested lands should be treated 

 witli gas-lime. This destroys the brown pupse and pre- 

 vents any mischief being done during the following season. 

 Ciwe. — (1) Hand-picking (by children) is one of the 

 mos teffectual remedies. (2) Poultry eat the pupge, and 

 are therefore of service in clearing the ground of this pest. 

 (3) Soot, salt, and sulphur are useful top-dressings. 



The Great Yellow Underwing Moth {Noctua 

 pronuba) belongs to the Noctuidai, a group of the Lepidop- 

 tcra, which are chiefly nocturnal in their habits. The moths 

 make their appearance in June ; and are known by the 

 dark-brown anterior and yellow posterior wings. The 

 eggs are kiid on certain plants in July. The larvse, 

 known as surface caterpillars, are nocturnal — feeding 

 during the night and hiding under clods, etc., during the 

 day. When mature, the larvae measure about one and 

 three-quarter inches long, and the colour of the integu- 

 ment varies from sage-green to brown. There is a dark- 

 brown band along the back, while the under side is of 

 a pale-green colour. The larvoi feed during the autumn, 

 and hibernate beneath clods of earth, etc. In the spring 

 (after feeding for a short time) these larvae construct 

 earthen cells, in which they turn to red pupse. The pupae 

 are transformed into moths in June or July. 



Prevention. — (1) Burn such weeds as bittersweet and 

 docks, as the caterpillars of N. pronuba feed on these 

 plants as well as on the varieties of cabbage. 



(2) The rook, jackdaw, chiff-chaff, blue-tit, and other 

 insectivorous birds destroy these farm pests. 



Cure. — Gas-lime, tobacco-water, soft-soap, lime, soot, 

 quassia, quicklime, and sulphur have been prescribed as 

 remedies. 



The Boll Worm {Heliothis armigera), which is the 



