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.
Phytoseiids as potential natural enemies of potato psyllids in organic potato production in South Texas, USA