Fig. 5.

Field experiment for assessing 2,4-D DMA efficiency in controlling late wilt. The experiment was conducted in an infested sweet corn field in the Hula Valley (upper Galilee, northern Israel). The Jubilee cv. field plants were treated separately with Dimethylamine salt of 2,4-D (2,4-D DMA, 96.9 % active ingredient, Aminobar, Luxembourg Industries Ltd., Israel). The treatment was done at a dosage of 150 cm³/0.1 ha and applied three times. a. The control (untreated) and 2,4-D DMA treated groups of Jubilee maize plants in the field were photographed 62 and 71 days after sowing. b. Root, stem and leaf samples were inspected for the presence of pathogen DNA using PCR amplification of the unique H. maydis oligonucleotide (marked as H. maydis) 75 (upper panel) and 89 (lower panel) days after sowing. rDNA – amplified 18S eukaryotic ribosomal DNA; DDW – distilled and deionized water used as a template in the PCR mixture to ensure the absence of DNA contamination; and H. m.– DNA from 7-day-old Hnn maydis in vitro growth cultures used here as positive control for the unique DNA amplification. c. Yield assessment (in kg/m²) done 24 days after fertilization (DAF) (14/7/09, 84 days after sowing) that includes all upper part plant cobs in a 20-m-long section of each of the experiment rows. d. Wilt assessment done 17 (7/7/09) and 24 (14/7/09) DAF (77 and 84 days after sowing) for 100 plants in a sequence. The plants were classified as wilted when wilt symptoms appeared on the leaf whose cob is located in its axil. Bars indicate standard error