Search Results

You are looking at 1 - 3 of 3 items for

  • Author or Editor: Kiffnie M. Holt x
Clear All Modify Search

Seeds of tomato `Big Beef Hybrid' and impatiens `Sun and Shade White' were sown in 200-cell plug trays and put under cyclic mist to germinate. After 3 weeks, the most uniform seedlings were transplanted to 24-cell flat inserts where they remained for the duration of the experiment. At 5 weeks, plants were arranged for the study with three flats per treatment. The mechanical group was brushed 50 times at 7:00 a.m., 1:00 p.m., and 7:00 p.m. The brushing mechanism was adjusted as needed to account for growth and stimulate only the top 1 to 2 inches of the plants. Water was withheld from the drought plants until water stress symptoms developed. Treatments continued for three weeks. At the termination of treatment, data was only recorded on the eight plants in the middle of each flat to reduce edge effects. Data collected included height, total stem length, total leaf area, and fresh and dry weight of both roots and shoots. Two more replications of the experiment were performed over the next 3 months. As expected, the treated plants were shorter than the controls and had a more compact and sturdy growth habit in all replications. Effects on leaf area, fresh weight, and dry weight were noted and will be discussed.

Free access

Rooted chrysanthemum cuttings of five cultivars were transplanted into 6 1/2″ pots and greenhouse-grown for 7 weeks under natural daylength conditions. Plants were pinched back twice, on the 3rd week and the 5th week following transplanting. At 7 weeks, plants were arranged in a complete randomized-block design with four plants per cultivar per treatment and three replications. Spacing of the pots was kept constant through the duration of the experiment. The chemical group was sprayed with 2500 ppm B-Nine until run-off on the first day of treatment. The mechanical group was brushed 40 times, twice a day, for 5 weeks. The brushing mechanism was adjusted daily to account for growth so as to stimulate only the top 2 to 3 inches of the plant. Measurements of all plants were taken on the first and last day of the mechanical treatment. Data collected included height, internode length, and leaf area. Plants were then allowed to flower under the naturally shortening daylength, and the flowering date was recorded. The chemical and mechanically treated plants were shorter than the controls with a greater response occurring with the cultivars `Emily' and `Cheery Emily', which had a more open and upright growth habit. Cultivar response differences and effects on internode length, leaf area, and flowering date were noted and will be discussed.

Free access

Biological and chemical control strategies for the twospotted spider mite (TSM; Tetranychus urticae) were evaluated in a greenhouse experiment replicated over time in mixed production of ivy geranium (Pelgargonium peltatum ‘Amethyst 96’) and two impatiens cultivars (Impatiens wallerana ‘Impulse Orange’ and ‘Cajun Carmine’). Chemical control using the miticide bifenazate was compared with two release strategies for biological control using the predatory mite, Phytoseiulus persimilis. Specific treatments included 1) a single application of bifenazate at 0.3 g·L−1 formulation (22.6% a.i.); 2) a single release of predatory mites at a 1:4 predator to pest ratio based on sampled pest density; 3) a weekly release of predatory mites at numbers based on the area covered by the crop; and 4) an untreated control. TSM populations were monitored for 4 weeks. After another 4 weeks, when plants were ready for market, plant quality ratings were recorded. The number of TSM per leaf dropped for all treatments on all genotypes but increased in the untreated plants. On ivy geranium, the fact that there were significantly more TSM on untreated plants was not reflected in average plant quality, but it did reduce the proportion of containers rated as salable at full price compared with both chemical and biological control. On impatiens, both treatment and cultivar had significant effects on the mean plant quality rating and on the proportion of containers rated as salable at full price. The use of a sampling plan to determine the appropriate number of predators to release was as effective as the currently recommended management treatments for TSM in bedding plants.

Full access