J. B. Sieczka

Effects of short periods of chilling and warming on potato sugar content and chipping quality

Two days of chilling (exposure to 1 C) had no detectable effect on chip color or sugar content of potato (Solanum tuberosum L.) tubers. Four days of chilling led to increases in sugars if potatoes were stored at 10 C or 19 C for 3 to 4 days after chilling ended. Longer chilling gave increases in sugars by the end of the chilling period, and returning tubers to 10 C or 19 C magnified the response. Glucose and fructose gave similar increases from chilling treatments, except that glucose levels were consistently greater. Sucrose was increased by chilling, but the response pattern did not always resemble that of the reducing sugars. Twenty-seven days of storage at 19 C after chilling lowered levels of reducing sugars late in the storage season but not in December. Cultivars differed in response to chilling. Kennebec tubers accumulated far more reducing sugars but much less sucrose than did Norchip tubers. Storage at 19 C after chilling lowered the sucrose content of Kennebec and Monona while raising that of Norchip.ResumenTubérculos de papa (Solanum tuberosum L.), expuestos a períodos de frío (1°C) por dos días no sufrieron detectables efectos en cuanto al color que presentan rodajas de papa al freírse ni en el contenido de azúcar. Tratamiento de frío por un periodo de cuatro dias causaron un incremento en el contenido de azúcares cuando los tubérculos fueron almacenados a temperaturas de 10 o 19°C por espacio de 3 a 4 días después que el tratamiento de frio hubo finalizado. Períodos de frío más prolongados incrementaron el contenido de azúcares al final del período. Esta respuesta se magnifica si los tubérculos son almacenados a temperaturas de 10 o 19°C. Los contenidos de glucosa y fructosa respondieron similarmente al tratamiento de frío, exceptuando que los niveles de glucosa fueron consistentemente mayores. El tratamiento de frio incrementó el contenido de sacarosa, pero ésta respuesta no siempre se asemeja a la presentada por los azúcares reductores. El almacenaje a 19°C por espacio de 27 dias después del tratamiento de frío causo bajas en los niveles de azúcares reductores durante el último período de la época de almacenamiento, pero no en el mes de diciembre. Los cultivares responden diferentemente al tratamiento de frio. Tubérculos de la Variedad Kennebec acumularon mucho más azúcares reductores pero mucho menos sacarosa que los tubérculos de la Variedad Norchip. El almacenamiento a 19°C después del tratamiento de frío redujo el contenido de sacarosa de las Variedades Kennebec y Monona mientras que lo incremento en la Variedad Norchip.

Assessment of Pesticide Use in The U.S. Potato Industry

Pesticide use in US fall crop potato production was surveyed for the years 1990 to 1994. The purpose of the study was to provide information about the relative importance of each pesticide and potential alternatives. The objectives were to: (1) inventory pesticides used on potatoes, (2) rank the target pests and (3) estimate the economic value of the major pesticides. Extension specialists working on potatoes in twelve states provided the main source of survey data. The most commonly used pesticides in four categories were: fungicide —chlorothalonil, insecticide —methamidophos, herbicide —metribuzin, and “other” -diquat. The most frequent target pests were: early blight (Alternaria solani), late blight (Phytophthora infestans), aphids (primarily Myzuspersicae), Colorado potato beetle (Leptinotarsa decemlineata), lambsquarter (Chenopodium album), and pigweed (Amaranthus spp.). The pesticides that provided the most annual value to potato growers were methamidophos (

Eva:A midseason golden nematode- and virus-resistant variety for use as tablestock or chipstock

281 million), diquat (

Pike: A full season scab and golden nematode resistant chipstock variety

86 million), metribuzin (

Elba: A late maturing, blight resistant potato variety

81 million), CIPC (

The effects of handling on chip color and sugar content of potato tubers

56 million) and esfenvalerate (

Potato planter performance and effects of non-uniform spacing

52 million).

Hudson: A high yielding variety resistant to golden nematode

Eva is a new potato variety being released by the New York and Pennsylvania Experiment Stations. Eva is notable for its bright clear skin and attractive round to oval shape. It produces a chip color comparable to Monona from 9 C storage and has specific gravity 014 less than that of Atlantic. It has exceptionally long tuber dormancy and has extreme resistance to PVX, PVY, and race RO1 of the golden nematode. Scab resistance is like that of Monona. It is expected that Eva will find primary acceptance as a tablestock variety.ResumenEva es una nueva variedad de papa recientemente liberadad por la Estación Experimental de Pennsylvania y Nueva York. Eva se caracteriza por su piel clara y brillante y una atractiva forma semi ovalada. Produce hojuelas de un color similar a las de Monona, se almacena desde 9°C y su gravedad específica es 014 menos que Atlantic. Los tubérculos poseen una dormancia excepcionalmente larga y tiene resistencia extrema a PVX, PVY y la raza RO1 del nematodo dorado. La textura de su cáscara es similar a la Monona. Se espera que Eva sea aceptada como una variedad favorita para la mesa.

Rosa: A new golden nematode resistant variety for chipping and tablestock

Pike is a chipstock variety released jointly by the Cornell and Pennsylvania Experiment Stations in March 1996. Pike has a specific gravity comparable to Atlantic and the ability to produce light-colored chips after 7 C storage. Most of the chip color data were taken in December, January, and February. It has scab resistance comparable to that of Superior and is golden nematode resistant. It is a full season variety, somewhat earlier than Snowden. In 23 trials in New York, internal necrosis and hollow heart of Pike was 5% compared to 18% for Atlantic. When grown at high temperatures, Pike is susceptible to a unique expression o f heat necrosis that is net-like in appearance which is different from the internal brown spot of Atlantic. The yield has been about 95% of the yield of Atlantic.

Andover: An early to midseason golden nematode resistant variety for use as chipstock or tablestock

Elba is a high yielding cultivar which combines resistance to the golden nematode, foliar infection byPhytophthora infestans andAlternaria solani, andVerticillium wilt. Elba is a late maturing tablestock cultivar especially well adapted to organic soils. In small plots and on farmers’ fields it has demonstrated its worth in reducing the need for foliar fungicides to prevent blight.ResumenElba, es una variedad de alto rendimiento que combina la resistencia al nematodo dorado de la papa, a las infecciones foliares porPhytophthora infestans yAlternaria solani, y a la marchitez porVerticillium. Elba es una variedad importante de maduración tardía especialmente adaptada a suelos orgánicos. En parcelas pequenas, y en campos de los agricultores, ha demostrado su valor en la reduccion de la necesidad de aplicar fungicidas foliares para prevenir el tizön.