461 ● July–September 2006 16(3) Performance of Containerized and Bare- root Transplants with Soil Fumigants for Florida Strawberry Production James P. Gilreath 1 , Bielinski M. Santos 1 , Joseph W. Noling 2 , Salvadore J. Locascio 3 , Donald W. Dickson 4 , Erin N. Rosskopf 5 , and Steven M. Olson 6 ADDITIONAL INDEX WORDS. Fragaria ×ananassa, ring nematode, nutsedge, methyl bromide, 1,3-dichloropropene, chloropicrin, metam, napropamide SUMMARY. Field studies were conducted in three Florida locations (Bradenton, Gainesville, and Quincy) during 1998–99 and 1999–2000 to: 1) compare the performance of two transplant systems under diverse MBr alternative programs in ‘Chandler’ strawberry (Fragaria ×ananassa), and 2) determine the efficacy of these treatments on soilborne pest control in strawberry. Fumigant treatments were: 1) nonfumigated control, 2) methyl bromide plus chloropicrin (MBr + Pic) at a rate of 350 lb/acre, 3) Pic at 300 lb/acre and napropamide at 4 lb/acre, 4) 1,3-dichloropropene (1,3-D) plus Pic at 35 gal/acre and napropamide at 4 lb/acre, 5) metam sodium (MNa) at 60 gal/acre and napropamide at 4 lb/acre, and 6) MNa followed by 1,3-D at 60 and 12 gal/acre and napropamide at 4 lb/acre, respectively. Strawberry transplants were either bare-root or container- ized plugs. There were no significant fumigant by transplant type interactions for strawberry plant vigor and root weight per plant, whereas ring nematode (Criconema spp.) and nutsedge (Cyperus rotundus and C. esculentus) populations, and total marketable fruit weight were only influenced by fumigant application. The nonfumigated plots had the lowest strawberry plant vigor and root weight per plant in all three locations. In most cases, plant vigor and root biomass per plant increased as a response to any fumigant application. With regard to the transplant type, bare-root transplants had similar plant vigor as plugs in two of the three locations. Fumigation improved nutsedge and ring nematode control. All fumigants had higher early and total marketable yield than the nonfumigated control, whereas transplant type had no effect on total fruit weight. 1 Professor and Assistant Professor of Horticulture, respectively, Gulf Coast Research and Education Center, University of Florida, Wimauma, FL 33598; e-mail: bmsantos@ufl.edu. 2 Professor of Nematology, Citrus Research and Education Center, University of Florida, Lake Alfred, FL 33850. 3 Professor Emeritus of Horticulture, Horticultural Sciences Department, University of Florida, Gaines- ville, FL 32611. 4 Professor of Nematology, Entomology and Nematol- ogy Department, University of Florida, Gainesville, FL 32611. 5 Microbiologist, Agricultural Research Service, United States Department of Agriculture, Ft. Pierce, FL 34945. 6 Professor of Horticulture, North Florida Research and Education Center, University of Florida, Quincy, FL 32351. (Simonne et al., 2003). However, MBr is being phased out according to the Montreal Protocol, because it is an ozone-depleting molecule (Watson et al., 1992). During the last decade, vari- ous molecules have been proposed as MBr replacements to control soilborne diseases, nematodes, and weeds in polyethylene-mulched crops. Among those alternatives, the application of 1,3-D + Pic has been demonstrated to be an effective means to reduce the in- cidence of soilborne diseases in tomato (Lycopersicon esculentum) (Jones et al., 1995). De Cal et al. (2004), testing various alternatives to MBr in Spanish strawberry nurseries, found that Pic and 1,3-D were comparable to MBr for soilborne disease control. However, 1,3-D + Pic has weak activity against troublesome weeds, such as nutsedge (Noling and Gilreath, 2002). Another molecule that has been indicated as a MBr alternative is MNa, which is a broad-spectrum fumigant that upon soil application generates methyl isothiocyanate (Ajwa et al., 2003a). This fumigant has been tested in a variety of conditions with mixed results. Locascio et al. (1997) and Fennimore et al. (2003) suggested that MNa failed to reach the soilborne pest control levels of MBr + Pic, whereas other research has found that it can be a viable MBr alternative (Ajwa et al., 2003b). Despite these discrepancies, MNa is a relatively low-cost and versa- tile product that could be soil-sprayed or drip-applied, and further research is necessary to determine its efficacy in combination with other materials. The use of herbicides to complement the activity of MBr alternatives against weeds has been proposed for mulched- vegetable crops (Noling and Gilreath, 2002). The herbicide napropamide applied in preemergence is currently labeled for use in strawberry and pro- D uring 2004, U.S. strawberry production represented more than $1.47 billion in gross value [U.S. Department of Agriculture (USDA), 2005]. Florida is the second leading state in the U.S. in planted area and value with 7100 acres and $178 million, respectively (USDA, 2005). Strawberry harvest in Florida occurs between December and March, when other growing states are not planting the crop, allowing local growers to take advantage of high market prices during winter and early spring. Traditionally, strawberry is trans- planted in polyethylene-mulched beds with drip irrigation and the soil is treated with MBr + Pic to control soil- borne diseases, nematodes, and weeds Units To convert U.S. to SI, To convert SI to U.S., multiply by U.S. unit SI unit multiply by 29.5735 fl oz mL 0.0338 0.3048 ft m 3.2808 0.0929 ft 2 m 2 10.7639 3.7854 gal L 0.2642 9.3540 gal/acre L·ha –1 0.1069 2.54 inch(es) cm 0.3937 16.3871 inch 3 cm 3 0.0610 1.1209 lb/acre kg·ha –1 0.8922 0.0254 mil mm 39.3701 28.3495 oz g 0.0353 6.8948 psi kPa 0.1450 2.2417 ton/acre t·ha –1 0.4461