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- Author or Editor: G. A. Anderson x
Abstract
Resistance to the twospotted spider mite (Tetranychus urticae Koch) of 18 cultivars of ivy geranium [Pelargonium peltatum (L.) L’Her ex Ait.] was evaluated under greenhouse conditions by mass screening, by measuring fecundity on isolated leaves, and by paired leaf tests for selected cultivars. ‘Sybil Holmes’, ‘Yale’, and ‘Cornell’ were among the most susceptible, whereas ‘Double Lilac White’, ‘Sunset’, and ‘Salmon Queen’ were relatively mite-free. ‘Madeline Crozy’ and ‘Cornell’ were preferred for oviposition over the resistant ‘Double Lilac White’. Mite resistance was not related to density of simple or glandular leaf trichomes, but there was an apparent relationship between mite susceptibility and severity of oedema.
Abstract
Flower yields from October to May increased with the duration of supplementary lighting. Lighting improved flower yields by increasing bottom breaks, stimulating axillary shoot development after flower removal, and slightly reducing the days from cut-to-cut. Development of additional axillary buds was the principal factor in the improved branching of lighted plants. Excessive plant branching from supplementary lighting during a 7-month flowering period reduced significantly flower stem length, node number, and fresh wt of cvs. Shocking Pink and Red American Beauty. The 6.2 w/ft2 of incandescent light after the high intensity lighting period improved the flower quality of ‘Forever Yours’ but not of ‘Red American Beauty’. Plants lighted 9, 12, or 21 hr daily had fewer blind stems than unlighted plants.
Abstract
Stock plants of Chrysanthemum morifolium Ramat. cv. ‘Bright Golden Anne’ lighted continuously from September 30 to May 15 with Multivapor and Lucalox lamps (100 W/m2) produced more cuttings than those receiving only seasonal daylight and photoperiod lighting. High intensity supplementary lighting improved cutting quality by increased fresh and dry weight and stem diameter. Cuttings from plants receiving high intensity lighting rooted in fewer days, had greater root fresh and dry weights, and greater top fresh weight than plants lighted photoperiodically. After transplanting, the cuttings given high intensity light became established more rapidly and developed into flowering plants of higher quality.
Abstract
Costs were estimated for vegetatively producing plants of broccoli (Brassica oleracea L. (Italica group) through tissue culture with 3 culture stages and growing the plants 7 weeks in the greenhouse to field transplant size. The analysis was based on producing 11,000 finished transplants per week. Unit costs were estimated at 11.6¢ for tissue culture production of each plantlet and an additional 3.8¢ greenhouse cost for growing to transplant size.
Abstract
Continuous high intensity supplementary lighting from October to March with a combination of Lucalox and Multivapor lamps at 116W/m2 reduced the number of days to root vegetative cuttings of chrysanthemum, geranium and poinsettia and increased root number, length, and fresh weight over non-lighted cuttings. Lighting benefits were lost at 174W/m2 when foliar chlorosis developed and delayed rooting and reduced root growth. Leaf temperature of misted cuttings receiving 116W/m2 and 174W/m2 of supplementary light on sunny December days were 2.7° and 5.1°C, respectively, higher than non-lighted leaves.
Abstract
No relationship was observed between the population of ice nucleation active (INA) bacteria and the temperature at which ice formed in peach [Prunus persica (L.) Batsch] shoots. The ice nucleation temperature remained stable throughout the year, even during periods when INA bacteria were not detected. An intrinsic ice nucleating substance seemed to be responsible for initiating ice formation and limited supercooling to about —2°C. The ice nucleating agent seemed to be a constitutive component of mature wood and was stable under a range of chemical treatments. Ice nucleation was influenced by sample mass, temperature, and length of exposure. The freezing behavior of peach shoots was best described using a stochastic model of ice nucleation.
Abstract
Experiments were conducted to determine the relative contributions of bacterial and nonbacterial ice nuclei to freezing of peach [Prunus persica (L.) Batsch] shoots. Exposure to 33°C for 3 hr eliminated bacterial ice nuclei active at −3° on inoculated shoot pieces, but controls were not affected. In another experiment, ice nucleation temperatures and ice nucleation-active (INA) bacterial populations of field-collected shoots were determined. Mean freezing temperatures of 20 g (fresh weight) shoots were not significantly different in the presence or absence of INA bacteria (detection limit of 10 cells/g fresh weight). INA bacteria were detected on 19% of the shoots with a maximum natural population of 180 cells/g fresh weight. Inoculation studies indicated that 20 g fresh weight peach shoots contained a mean of 1.0 nonbacterial (−3°) ice nuclei, while shoots with 180 INA cells/g fresh weight averaged 1.4 (−3°) ice nuclei per 20 g. Most ice nuclei active at −3° were of nonbacterial origin.
Abstract
Ice formation was initiated between –0.6° and –2.6°C in mature Prunus persica (L.) Batsch trees growing in the field. Trees supercooled very little. Ice formation was initiated at several locations in the tree and subsequently spread throughout. The release of the latent heat of fusion following ice formation in the tissue maintained tissue temperatures 1° to 3° above air temperature for several hours and mitigated the tissue's response to ambient temperatures.
Abstract
The addition of 1.0% (wt/vol) ammonium peroxydisulfate to 0.125%, 0.25%, and 0.50% (wt/vol) ethephon sprays, applied before harvest to rutabaga (Brassica napus, Group Napobrassica Mill. cv. Laurentian) nearing commercial size, defoliated a greater percentage of leaves than would be anticipated from the effects of the individual components. Defoliation expressed on the logit scale was a linear function of the square root of the ethephon concentration, if ethephon was applied with or without ammonium peroxydisulfate. Chemical name used: (2-chloroethyl) phosphonic acid (ethephon).
Plantings of native flowers are often installed to increase the pollinator habitat in urban and suburban gardens. However, in many regions, it is not known which native plants are best used for pollinator plantings in gardens. Candidate plants must be attractive to pollinators, but they also must have attributes that gardeners find appealing. To identify native plants that are attractive to gardeners, we disseminated two surveys. The first asked gardeners to use a 5-point Likert scale to rate how likely they would be to garden with 23 flowering plants native to the Pacific Northwest United States. The second survey asked gardeners to use a 5-point Likert scale to rate how likely they would be to garden with a subset of 11 of these 23 native plants before and after receiving information about each flower’s attractiveness to bees (Anthophila). Using the first survey, we found a high level of acceptance of native plants by home gardeners (6 of 23 flowers had a mean “likelihood of planting” score of ≥ 4). Additionally, gardeners stated their likelihood of planting these native species increased significantly after receiving information about the bees associated with each plant. Across both surveys, gardeners who identified as “native plant gardeners” stated they would be significantly more likely to garden with all native plant species. Both surveys included an opportunity to share open-ended comments, which revealed that gardeners were most concerned with flower aesthetics and the aggressiveness of growth. Gardeners felt most positively about flower aesthetics and beneficial ecological traits. Many gardeners also commented that they needed more information or were unfamiliar with the plants. This study shows that native plants can have high baseline appeal to home gardeners. Specifically, we identified five native plant species that northwestern U.S. nurseries might consider growing and marketing as pollinator plants because of their high level of attractiveness to bees and home gardeners: globe gilia (Gilia capitata), california poppy (Eschscholzia californica), douglas aster (Symphyotrichum subspicatum), oregon sunshine (Eriophyllum lanatum), and common yarrow (Achillea millefolium).