Potato Leafhopper Control and Plastic Mulch Culture in Organic Potato Production

Abstract

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.