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- Author or Editor: David L. Morgan x
Nitrogen applied to ‘Roosevelt’ Boston fern in the greenhouse at 0, 25, 50, 100, 200, and 300 ppm concentrations increased dry weight, frond length, and leaf area up to 200 ppm, but all decreased at 300 ppm.
Mature acorns of the live oak (Quercus virginiana Mill.) were immersed for 0-60 minutes in 43.3 to 60.0°C (110 to 140°F) water baths. Various of those treatments produced up to 100% control of larvae of acorn weevils (Curculio sp.) in the seeds, but reduced acorn germination and radicle length to varying degrees.
Ficus benjamina L. and F. stricta Miguel. were exposed to various concentrations of ethylene gas and ethephon to determine their sensitivity to defoliation. F. stricta was more sensitive to ethephon, whereas F. benjamina was more sensitive to ethylene gas. Plants growing in medium exposed to ethylene gas depleted ethylene from the ambient atmosphere. Double-autoclaving the peat : perlite growing medium prevented ethylene depletion, indicating soil microbes as the source of depletion. Bacterial isolates from the medium depleted ethylene in vitro; fungal isolates did not deplete ethylene. The eight species of bacteria isolated into pure culture depleted 9% to 46% of the ethylene from the flask atmosphere over 5 days, with two Enterobacter spp. and one Pseudomonas sp. being the most effective depleters. Chemical name used: (2-chloroethyl)phosphonic acid (ethephon).
Live oak (Quercus virginiana Mill.) acorns harvested for commercial seedling production frequently are heavily infested by larvae of Curculio spp. (2). Many nurserymen routinely soak acorns for 30 min in 49°C water to kill weevil larvae before planting the seed (4). Microwave radiation is effective against some stored products pests, but it is too damaging for use against acorn weevil larvae (2). Crocker and Morgan (1) measured the short-term (12-day) effects of hydrothermal treatments of tree-harvested acorns on survival of weevil larvae and seed germination, using 0- to 60-min immersion of the seed in 43.3° to 60.0° baths. Treatment for any of the tested times at a minimum of ≈49° controlled 100% of the weevils; it also produced dosage-related plant mortality and reduction in the short-term growth of seedlings. In the present research, we examined the survival and long-term vigor of acorns that were exposed to a 49° hydrothermal treatment.