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Potato leafhopper (PLH) control and plastic mulch culture for certified organic potato production were evaluated in 2003 and 2004. The trials were conducted on the Rutgers Snyder Research and Extension Farm's certified organic fields. Production practices conformed to the National Organic Program. The potato cultivar grown was `Superior'. In 2003, PLH controls were: untreated control (UTC); Surround WP, 25 lb/acre; PyGanic EC 1.4, 1 pt/acre; Surround plus PyGanic; and silver plastic mulch. PyGanic and Surround/PyGanic treatment reduced PLH nymph counts and damage (hopperburn–HB), when compared to the UTC. Counts were higher and HB more severe in silver mulch plots than in the UTC, but marketable yield was more than double the UTC. PyGanic and Surround/PyGanic treatment yields were 50% higher than the UTC. In 2004, PLH controls were: PyGanic EC 1.4, 1–2 pt/acre; Diatect V, 2–4 lb/acre; and Surround WP, 25 lb/acre. The crop was grown on bare ground or silver plastic mulch. Nymph counts and HB were lowest on PyGanic- and Diatect-treated plots. Nymph counts and HB for UTC and Surround treatment were higher on plastic mulch than bare ground plots. Marketable yield was highest from PyGanic-treated plots. PyGanic or Diatect treatment yields were higher from plastic mulched than from bare ground plots. The PLH control and plastic mulch culture significantly increased organic potato yields. Marketable yield from the UTC was lower than the New Jersey average for conventional potato (275 hundred wt/acre) by 71% on bare ground and by 39% with plastic mulch in 2003; 59% on bare ground; and 52% with plastic mulch in 2004. PLH control with PyGanic combined with plastic mulch culture resulted in yields just 7% less than the state average; yield on bare ground was 26% less.

Control tactics for potato leafhopper (Empoasca fabae) in certified organic potato (Solanum tuberosum) production were evaluated in 2003 and 2004. The 2004 split plot trial also compared silver plastic mulch culture with bare ground culture. The trials were conducted at the Rutgers Snyder Research and Extension Farm's certified organic fields, and production practices conformed to the standards of the National Organic Program (NOP). `Superior' potato was grown both years. Potato leafhopper (PLH) controls evaluated were: kaolin, pyrethrin, pyrethrin plus kaolin (2003), pyrethrin with silicon dioxide (2004), and silver plastic mulch (2003). Pyrethrin, pyrethrin plus kaolin, and pyrethrin with silicon dioxide reduced PLH nymph counts and PLH damage (hopperburn) ratings compared with the untreated check (UTC). Kaolin did not reduce nymph counts or hopperburn ratings. In 2003, nymph counts and hopperburn ratings were higher in the mulch treatment than in the UTC, yet the mulch treatment produced higher yield than the UTC. In 2004, mulch culture increased total and marketable yield compared with bare ground culture when PLH was controlled. Nymph counts and hopperburn ratings were higher until mid-July in the mulch plots than bare ground plots with the UTC and kaolin treatments. Controlling PLH and using plastic mulch culture significantly increased organic potato yields and tuber size. Marketable yields from the UTC were less than the New Jersey average of 275 cwt/acre for conventionally grown potato: yield was 38% of average on bare ground and 68% of average on mulch in 2003; 33% of average on bare ground and 38% of average on mulch in 2004. Reducing hopperburn with pyrethrin on plants grown on mulch (2004) resulted in marketable yield that was 75% of the New Jersey average.

For the yellow-flesh fresh market, potato (Solanum tuberosum L.) cultivars with intense yellow-flesh are desired. The effects of clone, environment and clone × environment interactions on the intensity of the yellow-flesh trait in tetraploid potatoes were investigated. Twenty-four yellow-flesh clones, including 23 USDA selections and the check cultivar Yukon Gold, were evaluated for tuber yellow-flesh color as measured by a reflectance colorimeter in replicated field trials in Presque Isle, Maine in 1991 and 1992, and in Riverhead, N.Y., and Bridgeton, N.J., in 1992 and 1993. There were significant differences among environments and among clones for yellow-flesh intensity. The clone × environment interaction was also significant. Broad-sense heritability of yellow-flesh intensity was estimated as 0.93 with a 95% confidence interval of 0.92-0.97. The instabilities noted in some of these clones, although statistically significant, are of limited practical concern. The intensity of yellow-flesh will be an important trait for breeders to select in developing new yellow-flesh cultivars. However, in testing yellow-flesh clones for future cultivar release, the role of environment and clone environment interactions on other agronomic traits will probably be more important than the environment and clone environment interactions on the intensity of yellow-flesh.

Databases are commonly used to coordinate and summarize research from multiple projects. The potato (Solanum tuberosum) research community has invested significant resources in collecting data from multiple states and provinces, and we have developed a web-based database format for the use of researchers, farmers, and consumers. The northeast regional potato variety development project (NE1031) is a U.S. Department of Agriculture, Cooperative State Research, Education, and Extension Service (USDA-CSREES) regional project focused on developing and evaluating the suitability of new varieties and advanced clones from multiple breeding programs for a range of environments. This multistate project and its predecessors have been in existence for more than two decades, and they have resulted in the collection of a significant amount of standardized potato trial data. We have developed an interactive potato variety database that allows researchers and end-users to access and obtain potato variety trial results in one centralized site. The database is populated with the results of potato variety trials conducted in eight states (Florida, Maine, New Jersey, New York, North Carolina, Ohio, Pennsylvania, and Virginia) and two Canadian provinces (Prince Edward Island and Quebec). It currently contains over 35 data features and was developed primarily for scientists interested in potato variety development, growers, and allied industry members. Hypertext mark-up language (HTML) and hypertext preprocessor (PHP) were used to develop the database interface.