EFFECT OF NITROGEN AND MOISTURE STRESS ON SEVERITY OF MAIZE-DWARF MOSAIC-VIRUS INFECTION IN CORN SEEDLINGS

The impact of nitrogen and moisture stress on maize dwarf mosaic virus strain A (MDMV-A) in corn (Zea mays) was examined in a greenhouse exp eriment. The factors were MDMV-A, moisture, and nitrogen arranged in a factorial design, with each stress either present or absent. Moisture X nitrogen interaction was significant for number of leaves, plant he ight, and dry weight. MDMV X moisture was significant for dry weight. Ranking effect of stresses on MDMV titer, lowest to highest, was: adeq uate nitrogen and adequate moisture (no stress), and adequate nitrogen and inadequate moisture (moisture stress) < inadequate nitrogen and i nadequate moisture (dual stress) < inadequate nitrogen and adequate mo isture (nitrogen stress). Weeds that can increase moisture and nitroge n stress may need to have thresholds adjusted for cornfields in which the incidence of MDMV is high.