1920.] Potato Spraying Trials. 283 



(2) Two per cent. Bordeaux Mixture. — This was made by using 

 double the above amounts of copper sulphate and lime. 



(3) One per cent. Burgundy Mixture. — This was also made in 

 40 gal. tubs, 4 lb. of copper sulphate being dissolved in about 

 30 gal. of water ; 5 lb. of washing soda were then dissolved in 

 about 5 gal. of water and poured into the copper sulphate solution. 

 The mixture was well stirred and water was then added to make 

 up the 40 gal., when the mixture was again stirred. Every tub 

 was tested with red litmus, which turned blue. 



(4) Bordeaux Powder, bought ready made. 



The ordinary spraying machine was of the " cart " type, 

 the tank being formed by the bottom, sides and top of the 

 cart. This machine did 5 rows at once, and at full pressure 

 applied 85 gal. per acre from 3 nozzles per row. A new machine 

 of the barrel type was tested, with a large pump and 5 nozzles 

 per row (25 nozzles altogether), the extra pair of nozzles being 

 10 in. above the ordinary pair. This machine had a barrel 

 capacity of 120 gal., and applied 200 gal. per acre. 



The working of the 5-nozzle machine, with its larger pump, 

 is much harder for the horse, and also has the disadvantage 

 that it has to be filled at each end of the field when the field 

 is over 15 chains long. The cart type of machine is much easier 

 to fill by hand than the barrel type, as the liquid has only to 

 be lifted about 4 ft. 



The Bordeaux Powder was applied by means of a " Herrod's 

 Dry Sprayer." 



Harvestings — The potatoes were lifted by means of a spinner, 

 and the produce from each plot was clamped separately. 



Field I. — This field was the same as Field 2 in the previous 

 year's experiments. Its history is as follows : — 



I9I5 • 



. Potatoes 



10 cwt. superphosphate. 



I9I6 



. Onions 



3 



I9I7 . 



. Onions 



■ ■ 3 » 



I9I8 . 



. Potatoes 



10 ,, 



I9I9 . 



. Pota toes 



. . 20 loads of farmyard manure 



and 10 cwt. superphosphate. 



The variety of potato grown was Evergood (from Scotland), 

 and planting took place early in April. Each plot consisted of 

 9 rows, 28 in. apart, and was nearly | of an acre in area. The 

 potatoes were hfted from 22nd October to 29th October, and 

 were sorted and weighed in January. 



At the time ot the first spraying the weather was hot and 

 dry. but during the previous week light rain fell on 4 days. 

 The haulms of the potatoes were suffering from a moderate 

 attack of aphis, which got gradually worse during the hot 

 weather which followed the spraying. A few days after the 



