PLANT DISEASES. 93 



during the season there are three, each of which overlaps the one 

 following, so that a continuous supply of flies is forthcoming. 

 Methods of prevention by the use of chemicals are being explored, 

 but so far the results are not so hopeful as in the case of the carrot 

 fly. On the other hand, it has been found that hard varieties 

 of onions, such as White Lisbon and Blood Red, are much less 

 frequently attacked by the fly, if they can be got safely past the 

 seedling stage. Experiments in this direction have therefore 

 been instituted. 



Armstrong College, Newcastle-on-Tyne. * 



Wireworm Experiments. — In 1921 a series of experiments 

 was carried out on a 20- acre field in Cumberland which in 1920 

 grew a crop of swedes which was almost completely destroyed 

 by wireworms. The results have a bearing on methods of reducing 

 the losses incurred from this serious pest of the farmer. The 

 field was sown with " Captain " oats on April nth, under ex- 

 cellent conditions of soil and tilth, and the trial plots were laid out 

 to test the effects of rate of sowing and of manurial treatment. 

 It was found that on a good soil containing wireworms, extra 

 seeding alone is sufficient to produce a uniform crop; that the 

 addition of sulphate of ammonia with extra seeding is likely to 

 prove beneficial on poor soils badly infested with wireworms ; 

 that cross-sowing at the ordinary seed rate is advantageous on 

 good growing soil. Extra seeding might be useful on poor soil ; 

 but with extra seeding together with sulphate of ammonia on 

 good soil there is a danger of producing too rank a growth of 

 plant, with the result that the crop would be easily " laid." 

 It was further noticed that no migration of wireworms to the 

 headlands took place in the particular field under experiment 

 while it remained fallow. 



Black Fly on Beans. — Spraying experiments were carried out 

 in 1921 on a 5-acre field of beans which were badly infected with 

 black fly {Aphis rumicis). Different strengths of solutions of 

 Quassia chips and of paraffin with soft soap in water were tested. 

 Briefly, the results showed that spraying should be done at the 

 first signs of fly attack, and that a spray consisting of 3 oz. soft 

 soap, 4 oz. Quassia chips to each gallon of water is very effective 

 in its immediate results. It is important to check the spread of 

 the attack from the patches on which the Black Fly is first 

 observed. 



South Eastern Agrictdtural College, Wye. 

 Woolly Aphis. — A discovery of some importance has recently 

 been made with regard to this serious apple pest. Research 



