Joyce G. Latimer

Management strategy, shade, and landscape composition effects on urban landscape plant quality and arthropod abundance.

Abstract Intensity and type of management, the cultural variable shade, and the combination of woody and herbaceous annual and perennial plants were evaluated for their effect on key landscape arthropod pests. Azalea lace bugs, Stephanitis pyrioides (Scott), and twolined spittlebugs, Prosapia bicincta (Say), were most effectively suppressed in landscape designed with resistant plant species of woody ornamentals and turf. Landscapes containing susceptible plant counterparts were heavily infested by these two insect species in untreated control plots. A traditional management program of prescribed herbicide, insecticide, and fungicide applications effectively suppressed azalea lace bug and produced a high-quality landscape. Targeted integrated pest management with solely horticultural oils resulted in intermediate levels of azalea lace bug. Neither program completely controlled twolined spittlebug on hollies or turf. Carabidae, Staphylinidae, Formicidae, and Araneae were not reduced by any management strategy. Lace bugs (Stephanitis) were more common in plots with 50% shade than those in full sun. Spittlebugs (Prosapia) were more common in the shade during 1996 and in the sun during 1997. Spiders and ants were more often collected in full sun plots. Carabids, staphylinids, and spiders were more commonly collected from pitfall traps in turf than in wood-chip mulched plant beds, whereas ants were equally common in both locations. The addition of herbaceous plants to the landscape beds had little effect on pest insect abundance.

The effect of mechanical stress on transplant growth and subsequent yield of four cultivars of cucumber

Abstract Container-grown seedlings of four Japanese cultivars of cucumber ( Cucumis sativus L.), ‘Kurumeochiai-H’, ‘Chikanari-suhyoh’, ‘Nanshin’ and ‘Ritsurin’, were brushed with a suspended bar for 1.5 min twice daily for 12 days (short-term treatment) prior to being transplanted to raised beds in a plastic greenhouse. Brushing was continued on a selected group of plants for an additional 10 days (long-term brushing). Short-term brushing reduced the growth in dimensions of all cultivars and dry weight accumulation in all cultivars except ‘Kurume-ochiai-H’. Short-term brushing reduced the numbers of female flowers and fruits formed on lateral shoots developing on the treated portions of the main stem in ‘Chikanari-suhyoh’. Long-term brushing decreased the numbers of female flowers and fruits in ‘Nanshin’ and the number of flowers in ‘Chikanari-suhyoh’. However, these responses had no effect on the numbers of fruits harvested or individual fruit size or weight of these cultivars. Treatment had no effect on fruit yield except in ‘Ritsurin’ where both short- and long-term brushing decreased the total fruit weight but not number.

Comparing an IPM Pilot Program to a Traditional Cover Spray Program in Commercial Landscapes

Abstract An integrated pest management (IPM) pilot program for landscape plants was implemented during 1997 and 1998 on two commercial, two residential, and one institutional property managed by landscape professionals. When compared with preprogram, calendar-based cover spray program costs at these sites in 1996, the IPM program was cost-effective at one of the five sites in both 1997 and 1998, and cost effective at a second additional site in 1998 when the cooperator, initially skeptical of IPM, discontinued calendar-based cover sprays performed in 1996 and 1997. The mean cost per site was

Influence of Nitrate:Ammonium Ratios on Growth and Elemental Concentration in Two Azalea Cultivars

703.40 (preprogram),

An Entomogenous Nematode Steinernema carpocapsae is Compatible with Potting Media Environments Created by Horticultural Practices

788.26, and

Nitrogen, phosphorus, and potassium effects on pre‐ and post‐transplant growth of salvia and vinca seedlings

582.22 in 1996, 1997, and 1998, respectively. Volume of pesticide applied decreased a mean of 86.3% on the four sites not receiving cover sprays and increased 2.3% at site 2 (still using cover sprays) in 1997. In 1998, pesticide volume was reduced an average of 85.3% at all five sites compared with preprogram levels. The majority of insect pest problems were corrected using spot sprays of insecticidal soap or horticultural oil or by physical means such as pruning. One-third of the woody plant material on the commercial and institutional sites consisted of holly, juniper, and azalea. The most prevalent pests encountered were mites (Tetranychidae), aphids, lace bugs, scales, whiteflies, and Japanese beetle. Spiders were the most abundant group of predatory arthropod and ants, green lacewings, and lady beetles were also well represented in the managed landscapes.

Effect of pH on seedling growth of six cultivars of watermelon

Abstract Rooted cuttings of Rhododendron canescens “Brook” and Rhododendron austrinum were grown in sand culture with a modified Hoaglands solution under greenhouse conditions. The effect of varying ammonium:nitrate (NO3 −:NH4 +) ratios (100:0, 75:25, 50:50, 25:75, 0:100) on growth, chlorophyll content, plant quality, and elemental tissue concentration were determined. With NO3 − as the nitrogen (N) form, both azalea cultivars exhibited less vegetative growth, lower overall plant quality, with leaves showing visual chlorotic symptoms in comparison to plants receiving NH4 + as the N‐form. Leachate pH was highest with NO3 − as the predominate N‐form and decreased significantly with each increment of NH4 +. With both azalea cultivars, N‐form significantly influenced uptake and utilization of essential plant nutrients. Leaf concentrations of N, potassium (K), calcium (Ca), sulfur (S), boron (B), and molybdenum (Mo) were highest with NO3 −‐N. Leaf elemental concentrations of phosphorous (P), magnesium (Mg), copper (Cu), iron (Fe), manganese (Mn), and zinc (Zn) increased as NH4 + supplied more of the N‐ratio. Significant differences in Mg, Mn, and Zn were observed between species. Results from this study show that foliar N concentration is not an accurate indicator of plant growth response. Further investigations are needed to determine if foliarchlorosis and low growth rates observed with NO3 − fed plants due to an Fe deficiency, to low nitrate reductase (NR) activity in the leaves, or to a combination of these factors.

Calcium (45Ca2+) absorption by sorghum root tips during concomitant exposure to several surfactants

Three experiments were conducted to evaluate the effect of different potting media and horticultural practices on the infectivity of Steinernema carpocapsae (Weiser). Bioassays were conducted with ...

Effect of PCMBS on calcium‐ or aluminum‐induced curvature in roots of two watermelon cultivars

Abstract Pre‐ and post‐transplant growth of bedding plants is affected by seedling nutrition. However, there is little information available on how seedling nutrition affects the growth of ornamental bedding plants. In this study, we quantified the effects of nitrogen (N) (8 to 32 mM) and phosphorus (P) and potassium (K) concentration (0.25 to 1 mM) of the seedling fertilizer on pre‐ and post‐transplant growth and nutrient element content of salvia (Salvia splendens F. Sellow ex Roem. & Schult.) and vinca (Catharanthus roseus L.) seedlings. Shoot growth of salvia and vinca increased with increasing concentrations of N in the pre‐transplant fertilizer and these differences lasted until the end of the study at 15 days after transplanting. Pre‐transplant root dry mass of these species was not affected by the N concentration of the fertilizer, but root dry mass at 12 days after transplanting was positively correlated with the N concentration of the pre‐transplant fertilizer. Increasing N concentrations in the...

Container Size and Shape Influence Growth and Landscape Performance of Marigold Seedlings

Abstract Watermelon [Citrullus lanatus (Thunb.) Matsum and Nakai] cultivars Charleston Gray (CG), Crimson Sweet (CS), Dixielee (DL), Jubilee (JL), Mirage (MG), and Starbrite (SB) were grown in white quartz flintshot sand and watered daily with 0.01M sodium acetate buffer at pH 4.0, 4.5,5.0, 5.5, 5.0, or 6.5. After 14 days, stem length, leaf area, leaf, shoot and root dry weight, and number of lateral roots were measured. Number of roots increased with increasing pH from 4.0 to 5.0 in all cultivars except DL and CG. The number of roots of CG decreased with increasing pH. The number of roots of MG and SB had positive linear and quadratic correlations, respectively, with increasing pH. In all cultivars, root dry weight decreased with increasing pH from 4.0 to 5.5. At pH ≤4.5, all cultivars except CG had short or no tap roots and thickened lateral roots. CG had a decrease in stem length, leaf dry weight and area, and shoot dry weight with increasing pH, and was sensitive to high pH. However, MG and SB had an ...