39 



event, spraying must be begun some days before the average observer 

 will detect blight on the leaves, and the foliage should be kept well 

 coated with Bordeaux mixture up to the time the crop is harvested 

 or the tops are killed by frost. Do not stop for rainy weather; this 

 is just the time when late blight spores are formed in profusion, and 

 when infection most easily takes place. It is possible for a spraying 

 just before a rain, even though it is largely washed off, to do more 

 actual good than any other during the season. Moreover, properly 

 prepared Bordeaux mixture, if thoroughly applied, will withstand 

 severe washing if it once thoroughly dries on the leaves. The best 

 results are obtained when the mixture is forcibly applied in the form 

 of a fine mist, not in coarse drops sprinkled over the foliage. 



As is described elsewhere, the nozzles should be so arranged and of 

 sufficient number and adjustments as to cover the entire row at each 

 application. Do not limit the amount applied per acre to an arbitrary 

 number of gallons, but use enough at each application to thoroughly 

 coat the foliage, whether it requires 50, 100 or 150 gallons per acre. 

 Use a pump powerful enough to develop a pressure of at least 60 

 pounds with all the nozzles open. 



Formulas for Scab. 



Ji'ORMTJLA 1. 



Corrosive sublimate, ....... 2 ounces. 



Water, . . . . . . . . .15 gallons. 



The corrosive sublimate dissolves readily in water. Immerse seed 

 tubers for one and one-half hours in this solution. 



Formula 2. 

 Formalin (40 per cent solution formaldehyde), . 8 fluid ounces. 



Water, . . . . . . .15 gallons. 



Immerse seed tubers two hours in this solution. 



Formula 10. 

 For disinfection with formaldehyde gas: — 



Potassium permanganate, . . . . . .23 ounces. 



Formalin (40 per cent solution formaldehyde), . . 3 pints. 



The above is sufficient for each 1,000 cubic feet of space. Place 

 the seed tubers in bushel crates or shallow slat-work bins in a tight 

 room; spread the potassium permanganate evenly over the bottom 

 of a large pail or pan in an open spot in the centre of the room ; pour 

 the formalin over this, and give the dish one rapid tilt, to ensure 

 thorough mixing; leave the room at once, and tightly close from 

 without. The bins or crates should be so arranged that the gas can 

 circulate on all sides of them and mix with the air of the room before 

 it comes in contact with the potatoes. To avoid injury from the strong 

 gas as it is liberated, no potatoes should be placed directly above the 

 generator. 



Formulas for Beetles and Slugs. 



Formula 3. 

 Paris green, ........ ^ pound. 



Lime (unslaked), ....... 3 pounds. 



Water, .......... .50 gallons.' 



The standard remedy for the destruction of insects which eat the 

 foliage or fruit. The lime is added to prevent the Paris green from 

 burning the foliage. Slack the lime in a little water, and make a thin 



' An ordinary oil barrel holds about 50 gallons. 



