Steve George

RESISTANCE AMONG LANTANA CULTIVARS TO THE LANTANA LACE BUG, TELEONEMIA SCRUPULOSA (HEMIPTERA: TINGIDAE)

Abstract Lantana lace bug, Teleonemia scrupulosa Stål, (Hemiptera: Tingidae) is a primary insect pest of lantana, a landscape plant commonly grown across the southern United States. Twenty-eight cultivars of lantana were evaluated for resistance to lantana lace bug in replicated field plantings. Natural infestations of lantana lace bugs developed in mid-Jul, and were dispersed across all the replicates within 30 d in Dallas, TX. Populations of nymphs and adults were sampled bi-weekly from Sep-Nov 1996. Highest mean populations were present on ‘Patriot Desert Sunset’ (40.3 nymphs and adults/3-leaf sample/plant), ‘Pink Frolic’ (20.6) and ‘Patriot Sunburst’ (19.4). Nineteen of the cultivars exceeded 4 lace bugs per 3-leaf sample. Lace bugs were never detected on 3 cultivars, ‘Weeping White’, ‘White Lightning’ and ‘Weeping Lavender’ during the test period, and ‘Imperial Purple’, ‘Patriot Rainbow’ and ‘Denholm Dwarf White’ had seasonal means of only 0.1 total lace bugs per sample. Cultivars of L. montevidensis (K. Spreng.) Briq. (mean of 0.02 lace bugs/3 leaf sample) were highly resistant, whereas many cultivars of L. camara L. and L. hybrida hort (6.73 and 9.54 lace bugs/3 leaf sample, respectively) were susceptible. Cultivars with gold, red, purple, and white flowers had far fewer lace bugs than did cultivars with either orange/red, yellow, or bicolors of yellow with another color. These results indicate that within most flower colors or bicolors, there exists a range of resistance among the cultivars and usually at least 1 cultivar per color form with resistance to the lantana lace bug.

The Differential Grasshopper (Orthoptera: Acrididae)—Its Impact on Turfgrass and Landscape Plants in Urban Environs

ABSTRACT The differential grasshopper, Melanoplus differentialis (Thomas) (Orthoptera: Acrididae), frequently migrates from highway rights-of-way, pastures, and harvested fields to feed in urban/suburban landscapes and retail/wholesale nurseries across the southern and southwestern U.S.A., as these areas dry down during hot dry summers. Nine selected turfgrasses and 15 species of landscape plants were evaluated for their susceptibility or resistance to this grasshopper. Grasshoppers were collected from stands of Johnsongrass, Sorghum halepense, which was used as a standard host for comparison in both experiments. Based on feeding damage, number of grasshopper fecal pellets produced, and their dry weight, Zoysia matrella cv. ‘Cavalier’ was the least preferred grass followed by Buchloe dactyloides cv. ‘Prairie’ and Z. japonica cv. ‘Meyer’. Festuca arundinacea was significantly the most preferred host and sustained the most feeding damage, followed by Poa pratensis × P. arachnifera cv. ‘Reveille’ and 2 Cynodon spp. cultivars, ‘Tifway’ and ‘Common’. Among the landscape plants, Hibiscus moscheutos cv. ‘Flare’, Petunia violacea cv. ‘VIP’, Phlox paniculata cv. ‘John Fanick’, Tecoma stans cv. ‘Gold Star’, and Campsis grandiflora were the least damaged or most resistant. Plumbago auriculata cv. ‘Hullabaloo’, Glandularia hybrid cv. ‘Blue Princess’, Canna × generalis, Johnsongrass, and Cortaderia selloana cv. ‘Pumila’ sustained the most damage. Based on the number of fecal pellets produced and their weights, Canna × generalis and Glandularia hybrid cv. ‘Blue Princess’ were the most preferred landscape plants tested.

RESIDUAL CHEMICAL CONTROL FOR MELANOPLUS DIFFERENTIALIS (ORTHOPTERA: ACRIDIDAE) IN URBAN LANDSCAPES

Melanoplus differentialis (Thomas) (Orthoptera: Acrididae) and several other species of grasshoppers invade urban/suburban landscapes and retail/wholesale nurseries during the hot, dry summers in the southern United States to consume the foliage of many species of landscape plants and turfgrass. Two experiments were conducted to determine which insecticides could be used to safely provide residual control for the continual daily migration of grasshoppers in urban landscapes and nurseries. Leaves from treated Hibiscus moscheutos were harvested sequentially in time at 1-, 5-, and 11-days posttreatment and adult differential grasshoppers were confined on them for 24-, 48- and 72-hr exposures. Treatments with two synthetic pyrethroids, bifenthrin 0.66F (0.782 ml/liter) and lambda-cyhalothrin 9.52 WP (0.748 g/liter), provided 94 and 83%, mortality respectively, with 24-hr exposure to the 1-day-old treated leaves. Both chemicals provided 100% control of the grasshoppers during 72-hr exposure. The half rate (0.391 ml/liter) of bifenthrin also provided 89% control within the 72-hr evaluation. Treatments with diazinon AG600 (4.25 ml/liter) also provided 80-85% control with 72-hr exposure on the 1-day-old treated leaves. Acephate 75% S (0.803 g/liter) provided 33-39% control on the 1-day-old residues. Lambda-cyhalothrin provided 84% control with 72-hr exposure to the 5-day-old treated leaves. Residual control was also provided at 5 days by bifenthrin and acephate (53% and 46-50%, respectively). Most materials evaluated failed to provide any protection at all and none of the treatments provided residual control when grasshoppers were exposed to 11-day-old residues. No phytotoxicity to hibiscus was observed due to any of the treatments.

Performance of Landscape Roses Grown with Minimal Input in the North-central, Central, and South-central United States

Landscape roses (Rosa sp.) are popular flowering shrubs. Consumers are less willing or able to maintain landscape beds than in years past and require plants that are not only attractive, but well-adapted to regional climatic conditions, soil types, and disease and pest pressures. Marketing and distribution of rose cultivars occurs on a national level; therefore, it is difficult for U.S. consumers in the U.S. Department of Agriculture (USDA) Plant Hardiness Zones 3 to 5 to identify welladapted, cold-hardy cultivars. Identifying suitable cultivars that have strong genetic resistance to pests and disease and that will tolerate temperature extremes without winter protection in theUSDAPlantHardiness Zones 3 to 5 is of tremendous value to consumers and retailers in northern states. Twenty landscape rose cultivars, primarily developed in north-central North America, were evaluated at five locations in the United States (three in the north-central United States, one in the central United States, and one in the south-central United States) using the lowinput, multiyear Earth-Kind methodology. Six roses had ‡75% plant survival at the end of the study and were in the top 50% of performers for overall mean horticultural rating at each of the three north-central U.S. sites: ‘Lena’, ‘Frontenac’, ‘Ole’, ‘Polar Joy’, ‘Sunrise Sunset’, and ‘Sven’. Five of these six roses met the same criteria at the central United States (exception ‘Lena’) and the south-central United States (exception ‘Polar Joy’) sites. Cultivar, rating time, and their interaction were highly significant, and block effects were not significant for horticultural rating for all single-site analyses of variance. Significant positive correlations were found between sites for flower number, flower diameter, and overall horticultural rating. Significant negative correlations were found between flower number and diameter within each site and also between black spot (Diplocarpon rosae) lesion size from a previous study and overall horticultural rating for three of the five sites. Cane survival ratings were not significantly correlated with overall horticultural rating, suggesting some cultivars can experience severe winter cane dieback, yet recover and perform well. Data from this study benefit multiple stakeholders, including nurseries, landscapers, and consumers, with evidence-based regional cultivar recommendations and breeders desiring to identify regionally adapted parents.

Moisture and Nutrient Storage Capacity of Calcined Expanded Shale

Expanded shale (EXSH) is an important and increasingly popular soil conditioner with several horticultural applications, including its use as a soil amendment for clay textured soils (Sloan et al., 2002), as an ingredient in plant growing media (Sloan et al., 2010) or green roof substrates (Ampim et al., 2010 ). It is a lightweight material produced by firing mined lumps of shale at high temperatures in a rotary kiln in a process similar to that of clay ceramics. The resulting product can be screened to create various size fractions depending on the intended use. For example, Texas Industries (TXI) of North Texas, USA produces five size fractions of expanded shale that includes the following ranges, from smallest to largest, 0.07 to 0.60 mm, 0.60 to 2.0 mm, 2.0 to 4.8 mm, 4.8 to 6.4 mm, 6.4 to 9.5 mm, 9.5 to 12.7mm, 12.7 to 15.9 mm Expanded shale aggregates are suitable as components of planting media and soil amendments because, unlike most minerals, they are porous, stable, and resistant to decomposition (Ferguson, 2005). Expanded shale is believed to beneficially modify growth media properties by enhancing overall aeration, improving water and nutrient holding and release capacities, and promoting optimum plant growth (Blunt, 1988; Dunnett and Kingsbury, 2008). Sloan et al. (2002) found that expanded shale consistently improved overall plant performance better than quartz sand, sphagnum peatmoss and cottonseed hull when they were used as amendments for poorly-drained Austin silty clay soils suggesting its superiority as a soil conditioner for the production of horticultural crops on soils with poor tillage characteristics. In a similar way, Nash et al. (1990) found that a potting medium comprising a mixture of peat moss and expanded shale increased the growth and quality of petunia and impatiens. Smalley et al. (1993) also found that amending soils with products containing expanded shale did not hamper plant performance. Though growth index and plant dry weight of Salvia (Salvia splendens) and Vinca (Catharanthus roseus) increased with increasing fertilizer levels for all their treatments, the greatest performance of these plants were observed for treatments amended with the product containing expanded shale, granite sand and composted poultry litter. In another application, Forbes et al. (2004 and 2005) discovered that expanded shale is a potential sorbent for phosphorus in subsurface flow