PLANT DISEASES. 9! 



flies' choice of bare soil for egg-laying offers a possible line of 

 attack. 



Frit Fly in IVinier Wheat. — It has been shown that bad 

 attacks of Frit Fly occur on winter wheat following leys containing 

 either rye grass or Italian rye grass. Experiments extending 

 over three years and carried out on the University Farm have 

 shown that this is due to the fact that the autumn brood of flies 

 lay their eggs on the grass, and that the larvae feed on the shoots, 

 and after the grass is ploughed in they eventually migrate to 

 the young wheat plants. The field experiments were supple- 

 mented by pot experiments in the laboratory. One result of 

 the work has been that the Farm Manager has decided that it 

 is no longer profitable to grow wheat after rye grass, unless the 

 latter is ploughed in before harvest. 



University of Leeds. 

 Garden Chafer. — {Phyllopertha horticola). — As a result of some 

 trials on a Yorkshire farm it is believed that much improvement 

 has been effected in a grass field which owing to the White Grub 

 attack had for several years been losing condition. Some good 

 was done by dressing the field in Spring with agricultural salt ; 

 but the best results were obtained by adopting the plan, which 

 has frequently been recommended, of destroying the parent 

 beetles. Advantage. was taken of the beetles' habit of swarming 

 on young bracken to collect them by means of a scoop-and-box 

 apparatus devised for the purpose, the work of destroying them 

 being much facilitated by their being largely confined to the 

 injured field and its immediate vicinity. When the field was 

 inspected in November, 1921, it presented a healthy appearance, 

 and the tenant expressed himself as well satisfied that the 

 treatment had been effective. 



Wireworm Experiments. — In 1919 and 1920 experiments were 

 carried out in a field infested with wireworm to test the effect 

 of a dressing of 10 cwts. of crude naphthalene per acre in reducing 

 wireworm attack. The dressing was applied on October 22nd, 

 1919, and barley was sown in April, 1920. The growing period 

 of 1920 was favourable, so that is is somewhat risky to draw 

 conclusions from the experiment, but from the results obtained 

 it appears that a heavy crossing of crude naphthalene if applied 

 in autum.n will reduce in the course of the following winter the 

 number of wireworms in an infested field, and that, when wire- 

 worm attack is feared, it is well in the case of corn crops to 

 increase the rate of sowing. 



