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Zoysiagass (Zoysia japonica) use continues to expand on golf courses, home lawns, and sports fields in the transition zone. Unfortunately, the slow growth rate of the species and long establishment period have limited its use to those sites that can afford zoysiagrass sod. The development of sprig-planting techniques that can produce a zoysiagrass turf in a single season would considerably increase the use of this desirable species. A study was conducted over 2 years at two different regions in Arkansas to evaluate the efficacy of a new zoysiagrass net-planting technique (ZNET) on establishment of zoysiagrass from vegetative sprigs. The technique involves rolling the sprigs onto the site in cotton netting and top-dressing the sprigs with 1.0 cm (0.4 inch) of native soil. This technique was compared to a standard sprig-planting technique and a standard sprig planting that was also top-dressed with 1.0 cm of native soil. The standard treatments were planted according to established methods using freshly-harvested sprigs applied at a rate of 70.0 m3·ha-1 [800 bushels (1000 ft3) per acre]. Rate of turfgrass cover was monitored throughout the growing season. The ZNET planting technique significantly improved establishment over the traditional sprigging technique and the turf reached about 85% cover by the end of the growing season (120 days). Top-dressing a traditionally sprigged area with native soil also improvedestablishment compared to traditional sprigging and was comparable to the ZNET technique. It was concluded that the ZNET technique did improve establishment rates of zoysiagrass, but the same results could be attained by top-dressing sprigs that were planted with a standard planter.

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The greenhouse orthezia (Orthezia insignis) is a serious and widespread pest of cultivated lantanas (Lantana sp.) in warmer regions of the world. Forty species and cultivars of lantanas were screened for their relative susceptibility to this insect pest. Results showed that two Florida native lantanas, pineland lantana (L. depressa) and buttonsage (L. involucrata), were highly susceptible to infestation, with trailing lantana (L. montevidensis) and its cultivars and hybrids being somewhat less susceptible. Shrub lantana (L. camara) and its cultivars and hybrids were the least susceptible to greenhouse orthezia infestation, but some of these varieties are rather unattractive as landscape ornamentals and can become serious weeds.

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Woven polypropylene groundcloth is used extensively in plant nurseries as a permeable and durable surface for container plant production. To better understand the fate of overhead sprinkler irrigation water, we designed and constructed runoff platforms (2.7 m2) to measure runoff and leachate from single irrigation events as affected by slope and underlay substrates. Groundcloth-covered platforms at slopes of 1.5% and 11% were tested with each of five underlay treatments: no underlay, coarse sand, 50% coarse sand and 50% no underlay (CS50), gravel, and native sandy soil. We applied 0.9 cm of irrigation at 1.8 cm·h-1 and determined runoff and leachate volumes. Runoff percentage [runoff × 100%/(runoff + leachate)] increased at the 11% slope for each underlay treatment. Mean (n = 10) runoff percentages (RP) for the 1.5% and 11% slopes were 0.5% and 15.7%, respectively, for no underlay, 0.1% and 1.1% for coarse sand, 0.1% and 0.7% for CS50, 0.7% and 2.5% for gravel, and 0.1% and 3.1% for native sandy soil. The low RP observed indicate that a high percentage of nutrients and agrichemicals associated with container leachate would move into the underlying substrate or soil rather than directly running off into surface waters.

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After a century since introduction to North America from Europe, white pine blister rust, caused by Cronartium ribicola J.C. Fisch., is recognized as one of the catastrophic plant disease epidemics in history. It has not yet stabilized and continues to spread and intensify. Its nine native white pine hosts comprise major timber producers, important watershed protectors, keystone ecological species, and the oldest trees on earth. All are highly susceptible and some have been damaged severely in parts of their native range, as well as where they have been planted as exotics. Resistance, the most promising approach to control, requires understanding of genetic interactions between hosts and pathogen, a quest that has been ongoing for half a century. Unlike other hosts of spectacular exotic diseases, such as chestnut blight [caused by Cryphonectria parasitica (Murrill) M.E. Barr] and dutch elm disease [caused by Ophiostoma ulmi (Buisman) Nannf.], white pines (Pinus L.) exhibit a surprising number of resistance mechanisms to blister rust, if at only low frequencies. There are three main kinds:

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Diosgenin is a steroidal aglycone occurring in certain species of Dioscorea native principally to eastern Mexico. In the 1940s, diosgenin became a much-sought-after intermediate for the chemical synthesis of certain corticosteroids and structurally related fertility regulants. Various difficulties of access to native sources led to attempts at plantation production. One of these, supported by the Upjohn Company between 1962 and 1980, was located on the Pacific coast of Guatemala and is described herein from the standpoint of technology development. The Dioscorea plant produces a long, coarse vine that requires support. The deep-growing, fleshy rhizome contains the diosgenin and, at harvest, must be removed from soil depths up to 1 m. Dry rhizome yield depends on supply of readily available (low-tension) soil water. Sites located over abundant water reserves give satisfactory rhizome yields, but diosgenin concentrations fall to uneconomically low levels under such circumstances. By 1980, diosgenin had been displaced by two products of soya oil processing, stigmasterol and sitosterol, which became available as a result of advances in microbial fermentation technology. Consequently, the cultivation of Dioscorea was abandoned.

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Pecans (Carya illinoinensis) are produced under a wide array of environmental conditions—from the warm humid southeastern states, to the continental climate of the central plains, to the arid climates of the American west. In addition, pecan cultural systems vary from the low-input management of native stands of seedling trees to the intensive management of single-cultivar pecan orchards. This wide diversity of pecan agroecosystems has fostered the development of innovative, site-specific approaches toward pecan pest management. Current pecan pest management programs require an intimate knowledge of orchard ecology. Growers use monitoring methods and prediction models to track pest populations. Biological control agents are conserved by habitat manipulation and/or augmented through inoculative releases. Selective pesticides are used to control target pests while conserving natural enemies. Four pecan cultural systems are described in detail to illustrate how ecological principles are applied to widely diverse pecan agroecosystems.

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Green roof technology in the United States is in the early development stage and several issues must be addressed before green roofs become more wide-spread in the U.S. Among these issues is the need to define growing substrates that are lightweight, permanent, and can sustain plant health without leaching nutrients that may harm the environment. High levels of substrate organic matter are not recommended because the organic matter will decompose, resulting in substrate shrinkage, and can leach nutrients such as nitrogen (N) and phosphorus (P) in the runoff. The same runoff problems can occur when fertilizer is applied. Also, in the midwestern U.S., there is a great deal of interest in utilizing native species and recreating natural prairies on rooftops. Since most of these native species are not succulents, it is not known if they can survive on shallow, extensive green roofs without irrigation. Five planting substrate compositions containing 60%, 70%, 80%, 90%, and 100% of heat-expanded slate (PermaTill) were used to evaluate the establishment, growth, and survival of two stonecrops (Sedum spp.) and six nonsucculent natives to the midwestern U.S. prairie over a period of 3 years. A second study evaluated these same plant types that were supplied with four levels of controlled-release fertilizer. Both studies were conducted at ground level in interlocking modular units (36 × 36 inches) designed for green roof applications containing 10 cm of substrate. Higher levels of heat-expanded slate in the substrate generally resulted in slightly less growth and lower visual ratings across all species. By May 2004, all plants of smooth aster (Aster laevis), horsemint (Monarda punctata), black-eyed susan (Rudbeckia hirta), and showy goldenrod (Solidago speciosa) were dead. To a lesser degree, half of the lanceleaf coreopsis (Coreopsis lanceolata) survived in 60% and 70% heat-expanded slate, but only a third of the plants survived in 80%, 90%, or 100%. Regardless of substrate composition, both `Diffusum' stonecrop (S. middendorffianum) and `Royal Pink' stonecrop (S. spurium) achieved 100% coverage by June 2002 and maintained this coverage into 2004. In the fertility study, plants that received low fertilizer rates generally produced the least amount of growth. However, water availability was a key factor. A greater number of smooth aster, junegrass (Koeleria macrantha), and showy goldenrod plants survived when they were not fertilized. Presumably, these plants could survive drought conditions for a longer period of time since they had less biomass to maintain. However, by the end of three growing seasons, all three nonsucculent natives also were dead. Overall results suggest that a moderately high level of heat-expanded slate (about 80%) and a relatively low level of controlled-release fertilizer (50 g·m-2 per year) can be utilized for green roof applications when growing succulents such as stonecrop. However, the nonsucculents used in this study require deeper substrates, additional organic matter, or supplemental irrigation. By reducing the amount of organic matter in the substrate and by applying the minimal amount of fertilizer to maintain plant health, potential contaminated discharge of N, P, and other nutrients from green roofs is likely to be reduced considerably while still maintaining plant health.

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Landfills are subject to public scrutiny because of potential environmental hazards, low aesthetic value, and rising costs of regulations governing landfill operation. In southwestern Virginia, landfill operators commonly seed landfills with nonnative perennial forbs and grasses. Our goal was to determine if wildflowers were a feasible alternative to the standard revegetation mixture. A standard landfill revegetation mixture and a wildflower mixture were sown at a landfill in Spring 1993 and were evaluated after one growing season. The number of species established in the wildflower mixture subplots was greater than in the standard mixture subplots, whereas cover of the two mixtures did not differ significantly. Rudbeckia hirta, Coreopsis lanceolata, Coreopsis tinctoria, and Hesperis matronalis thrived. Lespedeza cuneata was a confounding factor in determining cover estimates. Results of our study suggest that several native and naturalized species have potential for landfill restoration.

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In the 1970s, the U.S. Department of Agriculture (USDA) began developing low-chill-adapted highbush blueberry (Vacchizium corymbosum L.) for the southern United States (lat. 29° to 32°N) by using germplasm of the native southern species, V. darrowi Camp. This breeding work resulted in the release of several low-chill southern highbush blueberry (SHB) cultivars in the mid-1980s. These cultivars have been evaluated for yield and adaptation at several locations through the southern regional blueberry germplasm evaluation trials. These trials have shown that organic mulch is required for good performance of SHB. The one-fourth V. darrowi composition of SHB cultivars presents problems of freeze damage at some locations. This problem may be resolved by breeding cultivars through several alternative approaches.

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Summer squash (Cucurbita pepo L.) is grown in many temperate and subtropical regions, ranking high in economic importance among vegetable crops worldwide. A native of North America, summer squash has been grown in Europe since the Renaissance. There are six extant horticultural groups of summer squash: cocozelle, crookneck, scallop, straightneck, vegetable marrow, and zucchini. Most of these groups have existed for hundreds of years. Their differing fruit shapes result in their differential adaptations to various methods of culinary preparation. Differences in flavor, while often subtle, are readily apparent in some instances. The groups differ in geographical distribution and economic importance. The zucchini group, a relatively recent development, has undergone intensive breeding in the United States and Europe and is probably by far the most widely grown and economically important of the summer squash.

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