Chloropicrin, EPTC, and Plant Growth Promoting Rhizobacteria for Managing Soilborne Pests in Pine Nurseries

The effects of preplant soil treatments and seed treatment on seedling production and soilborne pests were evaluated on loblolly pine (Pines taeda) at three forest nurseries. Treatments were applied in 1998 at the Flint River Nursery (Byromville, GA) and at the Hauss Nursery (Atmore, AL). In 1999, treatments were applied at the Carter Nursery (Chatsworth, GA) and continued at Flint River Nursery. Soil treatments included 67% methyl bromide/33% chloropicrin at 350 lb/ac (MC33), EPTC (Eptam® 7-E), chloropicrin at 150 and 300 lb/ac (CH150 and CH300) and in combination with EPTC (CH1 50E and CH300E). At the Carter Nursery, a soil treatment of metam sodium at 80 lb/ac and chloropicrin at 150 lb/ac was added (M80/CH150). A seed treatment with the plant growth-promoting rhizobacteria (PGPR) Paenibacillus macerans was also evaluated with each soil treatment. In 1999, the EPTC herbicide treatment and PGPR seed treatment were reapplied to plots in the second-year crop at the Flint River Nursery. Fumigation and EPTC treatments did not significantly affect seedling density at the three nurseries by the end of the growing season. At the Flint River Nursery in 1998, seedling root collar diameter was greater in the CH300 and CHI 50E treatments, and seedling top weight was greater in the CH300 and CHI 50 treatments. No other differences in seedling size were observed among treatments. Seedling density at the Hauss Nursery was greater in plots with the seed treatment compared with untreated seed. At the Carter Nursery, there were fewer seedlings (2/ft) in the seed treatment plots, and at the Flint River Nursery, the seed treatment reduced seedling height in 1998 and 1999. No observed disease or insect problems occurred in any of the nurseries. The effect of fumigation with MC33 on soilborne Pythium and Fusarium spp. varied among the nurseries. In general, fumigation reduced populations of these fungi. Parasitic plant nematodes were reduced by all fumigants following fumigation at Carter Nursery. Nematodes were rarely observed in soil samples at the other nurseries. Nutsedge was seldom found in the fumigated plots at Flint River Nursery in 1998. By 1999 only the CH300 treatment had less nutsedge than the controls. EPTC was not effective for nutsedge control at Flint River Nursery. Populations of nutsedge at the Carter and Hauss Nurseries were very low.

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Author(s): Michelle M. Cram, Scott A. Enebak, Stephen W. Fraedrich, L. David Dwinell

Publication: National Nursery Proceedings - 2000