A M E R I C A N P O T A T O J O U R N A L 175

Potato Spraying in New York

DANIEL DEAN, Nzchols, Tioga County, N. Y.

We spray pota toes to keep a w a y diseases and insect pes ts which would reduce yield or spoil quali ty, or both. The degree of success reached is of ten measured by the t imeliness as well as the thoroughness of spraying. The old proverb that a s t i tch in t ime saves nine is h a r d l y forcible enough for pota to sp ray- ing, where success or failure often hinges upon a few days or even a few hours. Sp ray ing agains t a disease is the appl ica- tion of a d is infectant upon the exposed su r faces of the plant , which remains there, r eady to des t roy the disease germ when it arrives. Spray ing a f t e r the germ has reached the p l an t and gained an ent rance into its t issue is o f ten a was te of t ime and mater ia l . As the po ta to p l an t is g rowing cons tan t ly al- most to the end of its life, new surface is being exposed to the a t t acks of disease germs. Therefore sp ray ing mus t be repea t - ed a t intervals shor t enough to make certain tha t not more than a small percentage of the p lan t su r face is exposed a t any one time. Fo r up-s ta te New York condit ions f rom five to fifteen appl ica t ions are needed to p ro tec t aga ins t late bli.ght, depending upon a number of factors. Large and dense vines of the Green Mounta in t y p e need sp ray ing of tener than the

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176 A M E R I C A N P O T A T O J O U R N s L

smal le r vines of the Rura l type. Hil l- top soils genera l ly g row smal le r vines of any var ie ty than val ley soils, and the air on hi l l - tops is not so damp as down where val ley fogs may keep vines damp till 10 a. m.

Sp ray ing for control of la te bl ight mus t be both thorough and t imely . Unless the sp ray ing is thorough to cover every pa r t of the vine at each appl icat ion, the disease can enter any uncovered spot. Exper imen t s a t the Geneva s ta t ion have shown tha t is is possible to control la te bl ight by sp ray ing with hand pumps at pressures of 80 pounds and less bu t it is then neces- sa ry to use very large quant i t ies of bordeaux, 300 to 400 gal- lons per acre and ex t reme care in appl ica t ion to cover every pa r t of each vine, something f a r too cost ly fo r f a r m practice.

My own experience of twen ty- th ree seasons shows tha t under very severe conditions, f r equen t river fogs in summer, with soil rich enough to grow large vines, it is possible to prevent loss by rot to the limit of not over one-half of one per cent in any one season, and the vines have a lways lived through bl ight a t t acks with small damage at most. I have found tha t with p resen t spraying nozzles not less than 200 pounds pres- sure should be used. F o r the pas t fou r seasons I have used 300 pounds all the t ime wi th a 6-horse-power moto r sprayer . So f a r as control of late bl ight is concerned, it is possible to do a p rac t i ca l ly per fec t job wi th two nozzles to each row, slant- ing in f rom each side. Insect control~ however, is much easier with the use of three nozzles to the row, one above, and one on each side. In my experience I have found the pairs of drop nozzles between the rows infer ior to the Nixon type which is s l ight ly higher above the vines, bu t still is low enough to t ho rough ly sp ray the under sides of the leaves.

Theoret ica l ly , it is possible to prevent la te bl ight damage .by wa tch ing wea the r condit ions and then tho rough ly spray ing j u s t ahead of the t ime the disease is due to spread. In prac- tice, I f e a r tha t this idea will not work. The leas t slip, such as a broken sprayer , would mean a loss heavy enough to pay for .spraying for years to come. The sures t w a y to prevent bl ight is to sp ray at in tervals of seven to fou r t een days, de- pending on the rap id i ty of vine growth and the weather . Spe- cial a t ten t ion should be paid to the wea ther bureau warnings of the app roach of large s to rm areas. As la te bl ight spreads in t imes of wet, humid, c loudly wea ther a tho rough spray ing j u s t in advance of each s torm covers the vines wi th disinfec- t an ts j u s t when most needed.

The second grea t reason fo r spray ing is the control of insect pests. Spray ing began in the first place fo r the control of chewing insects, of which the Colorado po ta to beet le is the most famil iar . Arsenical poisons were used then as now. Soon a f t e r bo rdeaux began to be used growers noticed tha t while it is not a poison it acted as a repe l lan t to a number of insects. Two of these, the l ea f -hopper and the black flea-beetle are very

& K R R I O A X q P O T A T O J O U l t M J k l . , 17T

destructive. As they do not ent irely des t roy the vines as do the Colorado potato bugs, the damage is of ten not noticed. A grower who holds up to the su,n a leaf riddled by the flea- beetle will see tha t the total damage to the plant mus t be great . The leaf-hopper is a sucking insect. He is the cause of much if not most of the t ip-burn so of ten seen in New York s ta te potato fields.

Spray ing must be very g o o d to control ei ther of these in- sects. I t must be s ta r ted ear ly before they have mult ipl ied. I t mus t be at high pressure, even higher than is necessary to control late blight. The drier the weather , the more spray ing is needed. This is the opposite of sp ray ing for late blight, which must be most thorough in the wet wea the r which hinders the mul t ip l ica t ion of insect pests.

The greates t increase in potato spray ing in recent years has come in the use of bordeaux as a control measure for the leaf- hopper and the flea-beetle. This is f o r t u n a t e in t ha t there are a number of middle western states in which blight occurs at times, though less f r equen t ly than a long the At lant ic coast, and it is in these s tates t ha t insects are most destr~lctive to the pota to plant . As spray ing good enough to control the in- sects named will also control late blight and rot, these s ta tes are not so liable as f o rmer ly to losses f r o m the disease.

The Colorado potato bug is so easily control led where spray- ing with bordeaux is pract iced tha t it is only necessary here to note t h a t when an arsenical is used it should always be com- bined with bordeaux, and care taken to spray if possible jus t as the slugs hatch f rom the eggs.

Po ta to aphids are hard to fight. Nicotine su l fa te is the remedy, and the very highest pressure pract icable used. I have noted tha t where 300 pounds was used the aphids were la rge ly killed, whereas the use at 200 pounds was near ly a fa i lure .

Dust ing is a method of using the same mater ia ls used in sp ray ing excepting the wa te r used as a carrier . I t is a newer method than spraying. I was one of the first to use it in the United States, and had very good success in blight control, using a hand duster only. Up to date, I believe tha t it has not ye t given the same cer ta inty of results as spraying. I t is perhaps weakest aga ins t the black flea-beetle, and at its best when used against the pota to aphids. I believe t ha t grea t pro- gress is being made with dusting, and t h a t there is a s t rong chance tha t in the f u t u r e it may equal the effectiveness of sp ray ing

With either dus t ing or spray ing the best possible machines should be used, and of course, the best mater ia ls . Neither is of much use unless the pota to grower will look upon his spray- ing or dust ing as a very impor t an t par t of pota to growing, no more to be slighted than planting, cult ivating or digging.

A M E R I C A N P O T A T O J O U R N A L i79

HURST, R. R. An Investigation into the Cause of Misses in Potato Fields in Prince Edward Island during the Season of 1927. Rpt. Div. Bot., Dominion Exp. Farms, Ottawa, Can. (1927) p. 204, 205, 1928.

A high percentage of misses occurring in Prince Edward Is- land potato fields during the early growing season of 1927 prompted an investigation of the reason for poor germination. Observations were made on the basis of (a) storage history and conditions, (b) methods of seed treatment and subsequent care of sets, (c) methods of cutting and seeding, (d) methods of ap- plying fertilizer, (e) source of seed. In summing up the re- sults of his study the author lists the following factors as being responsible for misses:

(1) Seconds served as seed. (2) Seed pieces were constantly found with no eyes. (3) Fertilizer injury to seed-piece. (4) Inefficient working of planters causing accidental

"skips." (5) Undried treated seed placed in barns and basements in

unventilated piles for an extended period before seeding. (6) Backward weather conditions after seeding. It was found that a smaller percentage of misses occurred

with seed cut some weeks before planting which had been prop- erly dried after t reatment and turned repeatedly to facilitate ventilation. This practice is followed by growers of large acre- ages.

- -W. STUART.

Crop and Market News EASTERN SHIPPING STATES ACTIVE

(Contribution from the Bureau of Agricul tura l Economics)

The new-potato season in eastern states has been featured by exceptionally early carlot movement, by total shipments consid- erably lighter than last spring, and by higher prices than a year ago. Hopefulness of the situation this season is in decided con- t rast to the discouraging conditions last year, which resulted from excessive production in early 1928.

By the first of June, Florida was out of the picture and the season was rapidly closing in southern Texas, Louisiana and Ala- bama. Rains seriously damaged the Eagle Lake-Wharton crop in Texas. Shipments from Florida were slightly in excess of 5,- 000 cars, compared with 7,700 in 1928. The final total for Ala- bama was not expected to be over 1,500 cars, or only about half