American Potato Journal PUBLISHED BY

THE POTATO ASSOCIATION OF AMERICA SOMERVILLE, N.J. NEW BRUNSWICK, N. J.

O F F I C E R S A N D E X E C U T I V E C O M M I T T E E F. M. B L O D G ~ , P r e s i d e n t . . . . . . . . . . . . . . . . . . C o r n e n U n i v e r s i t y , I t h a c a , N e w Y o r k F. J . STgV~NSON, V i e s - P r e s i d e n t . . . . . U. S. D e p t . of A g r i c u l t u r e , W a s h i n g t o n , D. C. W ~ . H . MARTIN, Sec.-Treas . , E d i t o r . . . . A g r . E x p . Sta . , N e w B r u n s w i c k , N e w J e r s e y C. H . M ~ r z o ~ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. O. B o x 946, B a k e r s f i e l d , C a l i f o r n i a E. B. TUSSINQ . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ohio S t a t e U n i v e r s i t y , C o l u m b u s , Ohio E. J . "l~HmeT.~eR . . . . . . . . . . . . . . . . . . M i c h i g a n S t a t e C o l l e g e , E a s t L a n s i n g , M i c h i g a n J. G. RICHARD . . . . . . . . . . . . . . . . L o u i s i a n a S t a t e U n i v e r s i t y , B a t o n R o u g e , L o u i s i a n a

OBSERVATIONS ON POTATO PROBLEMS IN U N I T E D STATES 1

JOHN TUCKER 2

Department of Agriculture, Ottawa, Canada

Through this article I wish to express appreciation for kindly and courteous treatment received at the hands of many people connected with the potato industry, during a coast-to-coast trip through large com- mercial potato areas in the United States this year.

I had the privilege of calling on several hundred prominent growers, dealers, brokers, departmental and college officials, many of whom expressed the hope of making a similar trip some time. Not- ing everywhere a general desire for information concerning problems confronting the industry in other districts, I felt that members of the Potato Association of America might be interested in some of the observations recorded, particularly as many who may read this article materially helped to provide the details.

Starting early in January 1941 at New York, the trip extended to nearly one hundred potato growing and marketing centers in thirty- five States, and was completed by the end of June. The order in which the States were visited is as follows: New York (City and Long Is- land), New Jersey, Pennsylvania, Maryland, Washington, D. C., Vir- ginia, North Carolina, South Carolina, Georgia, Florida, Alabama, Louisiana, Arkansas, Tennessee, West Virginia, New York (West) , Ohio, Kentucky, Missouri, Kansas, Colorado, Wyoming, Utah, Call-

aContribution No. 22 from the Plant Protection Division, Production Service, Department of Agriculture, Ottawa, Canada.

2Chief Inspector, Plant Diseases.

2 THE AMERICAN POTATO JOURNAL [Vol. 19,

fornia, Oregon, Washington, Idaho, Montana, North Dakota, Minne- sota, Iowa, Nebraska, Wisconsin, Illinois, Indiana, Michigan.

The objects were to ascertain for our information and guidance ( I ) if Canadian seed potatoes, where used, were giving the satisfaction desired; (2) the trend in the use of new varieties; (3) the attitude toward southern tests for northern-grown seed; (4) the effectiveness of Florida tests; (5) the attitude and trend toward washing and brush- ing potatoes; (6) environmental effects on new varieties; (7) progress in Bacterial Ring Rot control; (8) irrigation practices in potato pro- duction; (9) attitude toward tuber-indexing and tuber unit work as a means of improving seed stocks; (IO) information on low-cost disin- fectants; ( i I) other relevant and useful information to improve quality in seed potatoes; in short, discussing problems of seed potato certifica- tion for mutual benefit.

Obviously, the space available will not permit a detailed report covering so much ground, and in any case it is only intended to sum- marize briefly the impressions secured as a result of discussions with specialists in their own home locations. Credit for information pro- vided can also only be acknowledged in a general way here but gratitude for this aid freely given is none the less sincere.

For brevity the observations are recorded in paragraphs under various headings.

NEW VARIETIES. THE CHIPPEWA is giving excellent yields in many northern districts and at suitable altitudes in other areas. This variety is reported to be especially profitable in muckland soil for washed potato trade, and a premium is paid for its attractive appearance. Apparently the Chippewa is not doing well south of New Jersey. The following criticisms were made--considered a tender variety where storage or growing conditions are below average--sprouts too soon in normal storage and is subject to dis- coloration in cold storage; sunscalds easily, and breakdown in transit rapid--susceptibility to leaf roll may limit wider use. The H O U M A is doing well in northern districts on account of good table and yielding qualities. Other areas report too numerous tuber set for sizing. Houma, Louisiana, after which it was named, has discontinued its use due to its susceptibility to Early Blight under local conditions. The K A T A I r D I N continues to increase in pro- duction and over a wider area. It has yielded well under drought and other adverse conditions and has displaced rurals in manv areas. Its susceptibility to common scab and hollow heart alone

1 9 4 2 ] TUCKER: POTATO PROBLEMS I N T H E U N I T E D STATES

limits its wider use in some districts. It was reported that SEBAGO production is increasing in northern districts where yielding quali- ties are very good, but other districts find it too late maturing for their purpose. It has established good resistance to late blight in the north, but it is quite susceptible to that disease in southern Florida, probably because of the reduced photoperiod. The S E Q U O I A is doing very well in many test plots. It will undoubtedly receive much wider distribution when its leaf hopper and flea beetle resist- ant qualities become better known, and supplies of good seed have been built up. It is more resistant to late blight than many vari- eties. I t is a long season variety and suitable only for the late market. The P O N T I A C is a red variety of excellent yielding and table qualities. It was released to compete with Bliss Triumph, but is somewhat later and is not a very popular potato on the markets. Foliage type is difficult to read for mosaic. Will prob- ably not continue very long in production. The W A R B A appears more suitable for market gardeners than for large-scale produc- tion. It is a very early high-yielding variety of good cooking qual- ity, but its deep and pink colored eyes are discriminated against when other sorts are available. The RE D WARBA, a mutation from Warba, is giving excellent results in middle-west tests. I t has good yielding qualities but breaks occasionally to splashes of white. It will probably continue with limited distribution. The E A R L A I N E is not widely known and its value appears uncertain at this time. It will not displace the Irish Cobbler. It has given good results in some districts but does not appear to be consistently good.

SOUTHERN TESTS FOR NORTHERN GROWN SEED. This refers to the planting of samples in southern states during the win- ter. The san~ples are drawn from various lots of certified seed grown in the northern states. The idea is to ascertain by this sample the percentage of disease present in individual lots of seed, and is intended as a check on a grower's crop to determine if much disease had been acquired after the final field inspections. The demand for this service has developed partly as a result of delivery of poor seed to table stock growers, and partly by certification set- vices in an effort to provide more reliable seed to the potato indus- try.

To summarize the interviews held on this subject, it would

THE AMERICAN POTATO JOURNAL [Vol. I9,

still seem that there is not yet a great demand for the service on the part of seed purchasers. The principal requests came from Long Island growers' organizations who are urging a southern plot check on all seed intended for sale in that area. Very few of the seed importers elsewhere showed much interest in the plan. The gen- eral opinion appeared to be that if samples are sent south for the purpose of securing readings with a view to refusing further field inspections on poor lots, then the idea was excellent, but if samples are sent to secure good readings on which to sell crops during the current season then the risk of manipulation of seed samples ren- dered the readings of doubtful value. There also appeared to be some uncertainty about the value of readings of some diseases espe- cially with some varieties under the southern environmental con- ditions. Some of the Long Island concerns have recently deemed it expedient and necessary to acquire greenhouse space to further check on readings by tuber-index methods, and it is expected this phase of the tests may be enlarged in the future. However, it can definitely be said for the certification officials who conduct the work and really put a lot of time and effort into the program that they feel the value of the tests far exceeds the costs incurred, amounting to about $ ioo per acre of southern plots.

Another phase of southern tests is that laid down by one or two of the Agricultural Departments in the south. In Alabama, for instance, a state that imports large quantities of seed pota- toes, they test seed potato samples without charge from stocks which will be grown elsewhere during the current season, but the progeny of which is intended for sale as seed in Alabama. If the sample yields come within 75 per cent of the IO highest yielding lots in the plots, then all properly graded potatoes grown from seed represented by sample is eligible for recommendation by the state, and official tags may be stamped "Tested and Approved in Alabama." The cost of this test plot work at Fairhope, Alabama, and which now covers the growing of approximately 5o acres of plots, is paid by the state to encourage the planting of good yield- ing lots of certified seed, and to discourage the sale of so-called "Selected Seed" within the state. Incidentally, information secured indicated that some other states are considering ways and means of discouraging the sale of uncertified potatoes as seed.

WASHING AND BRUSHING POTATOES, Indications point to this practice becoming more general in spite of the fact that it has

I942 ] TUCKER: POTATO PROBLEMS IN THE UNITED STATES 5

been discontinued by some shippers who found that the added cost exceeded the premium received. The fact that more sidings and warehouses are being equipped with washers, and the spread in price between washed and unwashed potatoes appears to be widen- ing in many of the larger markets, is evidence of this trend. Unfor- tunately, the spread appears to be widening more at the expense of unwashed potatoes than in a rising price level for washed, which means that the producer appears to be well on the way to assum- ing the added burden at no profit. Added to the cost of washing is that of drying which requires expensive machinery in some dis- tricts. The loss from breakdown, due to rots actually resulting from washing and drying have been remarkably small, but it is agreed that washed potatoes should always be marketed and con- sumed promptly, and not held for storage purposes. Brushing without washing is on the increase in some districts, but has been discontinued in others. Potatoes for brushing must be quite dry; if they are not, they may appear dirtier than before. Potatoes intended for seed should not be put through a brusher if potatoes affected with ring rot have previously been cleaned in the machine.

TUBER INDEXING. After hearing dubious remarks from one source about the value of tuber-indexing, it was a most pleasant surprise to find unanimity of opinion among those actually engaged in the work throughout the country that tuber indexing is of definite value, and is highly recommended as a means of improving and maintaining quality of seed stocks. It was agreed that the method was not perfect because some tubers which pass as indexed later proved diseased, but that point is insignificant compared with the value of locating disease in seed stocks more easily by tuber index- ing than can be accomplished in the field. Tuber indexing in con- junction with tuber unit seed plot work conducted under proper isolation is what the industry may eventually have to depend upon to maintain all seed stocks to present high standards. The number of glasshouses in use, under construction, or being provided for throughout the country, and intended for potato tuber-indexing is some further indication of its merit.

BACTERIAL RING ROT CONTROL. There is no doubt about Bac- terial Ring Rot having spread far and wide throughout the country during the past few years, and that all concerned are taking more interest in the situation. One encouraging feature, it is

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agreed, is that where diseased stocks are completely disposed of, proper sanitary measures taken, and new disease-free seed planted, all chances are in favor of complete control on that property. Another is seen in the extraordinary measures taken by some prominent growers and officials to keep the disease out of their seed stocks. In some cases smears are taken from every tuber intended for seed plots or are examined under an ultra violet light before indexing. The tubers are distributed to selected farms to grow in units by tuber lines for multiplication. The seed produced in this way may form the nucleus for foundation seed produced in various distant parts of the country.

A final decision about the value of the ultra violet light for Bacterial Ring Rot identification, compared with the smear method, is reserved by some operators, but has been fully accepted as satis- factory by others who have specialized in the ultra violet light work. However, it is the usual practice to check all doubtful material by smears. I t would seen: that a combination of the two, speeds up the work very materially and appears effective in the hands of operators experienced in the use of ultra violet light.

In conclusion it might be said that a more enthusiastic group than those found in the field of seed potato production and pest control in the U.S.A. would be difficult to find. The industry, gen- erally speaking, is not so prosperous as it should be. The whole trade is highly competitive and is working on margins that are far too slim, but prospects appear to indicate somewhat better condi- tions for the future. Let us hope this may be so.

W E E D S U S C E P T S O F T H E P O T A T O Y E L L O W D W A R F V I R U S

S. G. YOUNKIN*

CorneIl University, Ithaca, N. Y.

The proximity of clover fields to potato fields was correlated with an increase in the incidence of yellow dwarf of potatoes by Black ( I ) , and Mader (5). This association was not observed by Walker and Larson (6) in some Wisconsin areas. Recently, Hansing (4) reported the spread of the yellow dwarf virus in New York within small areas

*The writer wishes to acknowledge the helpful suggestions and criticisms of Dr. F. M. Blodgett.