215 Influence of Promalin Spray and Drench on Fern Numbers of Asparagus

Asparagus (Asparagus officinalis)plants were sprayed and drenched with different concentrations of Promalin (0, 250, and 500 ppm) The varieties for the spraying experiment were `Mary Washington', `Emeral', `UC-157-F1', and `UC157F2'. Six replications for each treatment were used in a randomized complete-block design. The drenching experiment used two varieties (Mary Washington and UC-157-F2) with six replications of each treatment in a randomized complete-block design. Pots were numbered and labeled for each experimental unit. Plants (ferns) were counted and recorded in order to obtain the initial number of ferns before or after the spraying or drenching. In the spraying experiment, the plants were sprayed to run-off using a hand sprayer whereas; in the drenching experiment, 1000 mL or 1 L of the solution was used to drench each plant. The response to the chemical was measured in two ways: weekly stimulation of emergence of new-shoots and percent increase in final number of shoots over the initial number. In the spraying treatments differences were not found among the treatments used. In the drenching experiment with `Mary Washington' variety, a lower initial number of ferns at 250 ppm as compared to the 0 ppm of Promalin (8.82 to13.00) was observed. Differences for `Mary Washington' variety was not found for cumulative number of ferns on weeks 1, 2, and 3. However, the percent increase in number of ferns was higher for the 250 ppm as compared to the 0 ppm (174.55% to 78.14%). `UC-157-F2' showed no difference among the different concentrations. This indicates a difference in varietal response.