Submitted to: HortTechnology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/15/2006
Publication Date: 4/1/2006
Citation: Gerik, J.S., Greene, I.D., Beckman, P., Elmore, C.L. 2006. Pre-plant drip applied fumigation for calla lily rhizome nursery. HortTechnology. Vol 16, pgs 297-300. Interpretive Summary: Calla lily bulbs are grown in open fields on the central coast of California. The harvested bulbs are used to produce flowering potted plants. The fields have traditionally been fumigated with formulations of methyl bromide and chloropicrin before planting. With the impending phase-out of methyl bromide soil fumigation due to its atmospheric ozone depleting properties, calla lily growers will require alternative methods to control weeds and diseases for continual production. Fumigants such as Midas ™ InLine ™, Trichlor ™, Vapam HL ™ and Multiguard ™, and SEP-100 ™ are possible alternatives to methyl bromide. These fumigants can be delivered in drip irrigation systems, permitting better distribution through the soil by the irrigation water. Two trials on 2 sites were conducted to test the efficacy of the before mentioned fumigants for the control of weeds and disease for the production of the calla lily bulbs. It was found that Midas, Inline and a combination of Trichlor and Vapam performed very well for disease and weed control. Multiguard and SEP-100 did not perform as well. The study shows that calla lily bulbs can be produced following fumigation with Midas, Inline, or a combination of Trichlor plus Vapam.
Technical Abstract: Two field trials were conducted from 2002 until 2003 to evaluate several chemicals as alternatives to methyl bromide for the production of calla lily (Zantedeschia sp.) rhizomes. Various rates and chemical combinations were tested. The chemicals were applied through a drip irrigation system. The chemicals included iodomethane, chloropicrin, 1,3-dichloropropene, metham sodium, furfural, and sodium azide. None of the treatments reduced the viability of seed of mallow previously buried in the plots. Propagules of nutsedge and calla, and seed of mustard were controlled by some of the treatments. Most treatments reduced the populations of soilborne plant pathogens including Pythium spp., Phytophthora spp., and Fusarium oxysporum. The incidence of disease caused by soilborne pathogens was reduced compared to the non-treated control. The number and value of harvested rhizomes were greater among all of the treatments, except for sodium azide, compared to the control. The harvested value of the crop for the best treatments was increased six fold compared to the control. A successful crop of calla rhizomes can be produced by combinations of iodomethane, chloropicrin, 1,3-dichloropropene, and metham sodium.