In past work, dichloropropene + 17% Pic (1,3-D + Pic) at 327 L·ha–1 plus pebulate provided good control of nematode, soil fungi, and nutsedge in mulched tomato (Lycopersicon esculentum Mill.) and is considered the best alternative for methyl bromide (MBr) + chloropicrin (Pic), which is scheduled for phase-out in the United States by Jan. 2001. Metam-sodium did not provide acceptable pest control. In the present study, metam-Na (295 L·ha–1 combined with Pic (168 kg·ha–1) + 4.5 kg·ha–1 pebulate, and 1,3-D + 35% Pic at 168 and 225 L·ha–1 + pebulate were compared to MBr-Pic (98-2% at 345 kg·ha–1 and 67-33% at 505 kg·ha–1). Fumigants were injected into the bed except metam-Na and pebulate were surface-applied and incorporated and drip tubing and mulch were applied. Marketable yields with MBr-Pic, 225 L·ha–1 1,3-D + Pic, and metam-Na + Pic were higher than with the check. Yields with metam-Na alone or with additional water before transplanting were similar to the check. Nutsedge was controlled with MBr-Pic and all treatments with pebulate. Nematode root-gall ratings were high on tomato grown without fumigants (8.9 rating on a scale of 0 to 10 with 0 = no galling), low with MBr-Pic (0.33), and intermediate with all other treatments (2.2 to 5.5) except with 168 L·ha–1 1-3-D + Pic (8.3). This study indicates that metam-Na + Pic + pebulate also is a possible alternative to MBr-Pic for tomato.
A much needed compilation of studies of a Neotropical elevation gradient
