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Premise: To genetically discriminate subspecies of the common reed (Phragmites australis), we developed real‐time quantitative (qPCR) assays for identifying P. australis subsp. americanus, P. australis subsp. australis, and P. australis subsp. berlandieri. Methods and Results: Utilizing study‐generated chloroplast DNA sequences, we developed three novel qPCR assays. Assays were verified on individuals of each subspecies and against two non‐target species, Arundo donax and Phalaris arundinacea. One assay amplifies only P. australis subsp. americanus, one amplifies P. australis subsp. australis and/or P. australis subsp. berlandieri, and one amplifies P. australis subsp. americanus and/or P. australis subsp. australis. This protocol enhances currently available rapid identification methods by providing genetic discrimination of all three subspecies. Conclusions: The newly developed assays were validated using P. australis samples from across the United States. Application of these assays outside of this geographic range should be preceded by additional testing. [ABSTRACT FROM AUTHOR]

Crops grown for bioenergy production are a mandated component of the United States energy portfolio. Giant miscanthus ( Miscanthus × giganteus) is a leading bioenergy crop similar in habit to the invasive plant giant reed ( Arundo donax). To characterize the environmental tolerance of giant miscanthus, we compared the soil moisture stress tolerance of giant miscanthus and giant reed under glasshouse conditions. We subjected both species to soil moisture conditions of severe drought (−4.2 MPa), mild drought (−0.5 MPa), field-capacity (control), and flooded soils. These conditions were applied to two cohorts: one in which soil moisture conditions were imposed on newly planted rhizome fragments, and one in which conditions were imposed on established plants after 8 weeks of growth in field-capacity soil. After 16 weeks, we harvested all plants, measured above- and belowground biomass, and evaluated the reproductive viability of rhizome fragments. The total biomass of each species under flooded conditions was not different from the field-capacity control groups regardless of cohort. However, drought did affect the two cohorts differently. In the cohort treated after 8 weeks of growth, mild and severe drought conditions resulted in 56% and 66% reductions in biomass, averaged over both species, compared with the controls. In the cohort treated for the entire 16 weeks, mild and severe drought conditions resulted in 92% and 94% reductions in biomass. Rhizome fragments from both species and both cohorts showed 100% viability following flooded and control treatments; drought treatments reduced rhizome viability in both species, with a greater impact on giant miscanthus. Although giant miscanthus does not appear to have the potential to escape and establish in relatively dry upland ecosystems, it does show tolerance to flooded conditions similar to giant reed. [ABSTRACT FROM AUTHOR]

Population phenology studies in the native range of a potential biological control agent are indispensable to understand and manage the establishment of populations. At the same time, is important to know the responses of this agent to climatic variation if it were to be released in its target range. The life cycle and phenology of the armored scale Rhizaspidiotus donacis Leonardi, 1920 (Hemiptera: Diaspididae) under field conditions in part of its native range, the southeast of Spain, was studied from 2008 to 2010 as part of an evaluation of this scale for biological control of the giant reed, Arundo donax L. (Poaceae) in the south-western United States and Mexico, as this rhizomatous grass becomes invasive and extremely harmful in riparian areas. The results observed were that R. donacis has one generation per year. The crawlers are the infective and dispersive life stage and they occurred during spring, from March to June and the reproductive period identified by the adult males emergence, was found from May to July. Temperature was one of the climatic variables considered with most influence on the variation of stages abundance. [ABSTRACT FROM AUTHOR]

Warm-season perennial grasses are a promising source of biomass for energy production in Southeast USA, and low-input production is desirable. With only residual fertility in the soil and no irrigation, this test compared biomass yields of eight grasses under low-input production: L 79-1002 energycane ( Saccharum hyb.), Merkeron and N51 napiergrass ( Pennisetum purpureum Schum.), three clones of giant reed ( Arundo donax L.), and two switchgrass ( Panicum virgatum L.) lines. For the first 2 years napiergrass maintained dry matter (DM) yields over 25 Mg DM ha year, and energycane yielded over 20 Mg DM hayear for 3 years. Switchgrass yields were lower (8.6 Mg DM ha year average of 4 years), but the biomass contained less moisture at harvest than the other, larger-stemmed grasses. Switchgrass biomass also had the lowest concentrations of N, K, and ash. Average yields of giant reeds were also low (6.4 Mg DM ha year), while ash and N concentrations were relatively high compared with switchgrass and energycane. In 4 years of production, energycane and napiergrass removed between 269 and 386 kg N ha and 830-1,159 kg K ha, while the other grasses removed significantly less of these nutrients. Giant reed removed 126 kg N ha and 193 kg K ha, and switchgrass removed 83 kg N ha and 140 kg K ha. In Southeast USA, it is possible to produce biomass from perennial grasses with minimal inputs but the high nutrient removal rates of some species suggest that it may not be sustainable for long periods of time. [ABSTRACT FROM AUTHOR]

Arundo donax (giant reed) is a tall clonal invasive grass which has impacted many riparian ecosystems in the US. Experiments tested the hypotheses (I) that defoliation would affect A. donax stem growth and leaf production and (2) that leaf damage or removal would influence A. donax photosynthetic rates using a combination of field and laboratory settings. Leaf defoliation did not affect the height of stems or the number of leaves per stem for plants growing at a field site. Leaf damage did not influence the electron transport rate (ETR) for damaged or adjacent leaves, and defoliated stems maintained ETR which were similar to those of undamaged leaves. These findings suggest that moderate to low levels of leaf damage and/or defoliation alone may not significantly influence growth of A. donax stems and leaves and, therefore, may not reduce A. donax persistence in a particular habitat. Further, these results provide a benchmark against which to judge the effects of management approaches which affect A. donax shoots. [ABSTRACT FROM AUTHOR]

Giant reed, Arundo donax L., is a large, bamboo-like plant native to the Mediterranean region. It has invaded several thousand hectares of the Rio Grande riparian habitat in Texas and Mexico. The United States Department of Agriculture- Agricultural Research Service (USDA-ARS) is investigating four herbivore insects as potential biological control agents for giant reed. One of the most important reasons for targeting this invasive weed is to reduce its impact on available water supplies, especially in the Rio Grande Basin. This study examined selected economic implications of this program for agricultural water users in the U.S. The research included (a) estimating the value of the water saved (to agricultural purposes) by reduction of giant reed, (b) benefit-cost analyses, (c) regional economic impact analyses, and (d) an estimate of the per-unit life-cycle cost of water saved during a 50-year planning horizon (2009 through 2058). Positive results related to the benefit-cost ratio, economic impact analyses, and competitive results for the per-unit life-cycle cost of saving water are associated with the biological control project for giant reed. The benefit-cost ratio, calculated with normalized prices, indicates $4.38 of benefits for every dollar of public investment. According to 2009 results for the economic impact analyses, economic output is $22,000, value-added is $11,000, and no employment is supported by the water savings from giant reed. Additionally, the per-unit cost of water saved is $44.08, a value comparable to other projects designed to increase water supply for the region. These results indicate this program will have positive net economic implications for the U.S. and the Lower Rio Grande Valley of Texas. [ABSTRACT FROM AUTHOR]

Impact by two potential biological control agents, Tetramesa romana Walker and Rhizaspidiotus donacis (Leonardi), on the invasive weed, giant reed, Arundo donax L., was assessed in a quarantine greenhouse before release. Tetramesa romana alone and T. romana plus R. donacis significantly damaged A. donax by suppressing leaf and stem lengths and stimulated production of side branches during a 12-week period. R. donacis plus T. romana only slightly more impacted the plant than did T. romana alone, most likely because of the longer life cycle of R. donacis that may require a longer period of time to cause measurable damage. No negative interactions were observed between the two candidate biological control agents. Therefore, based on their potential to significantly damage A. donax under greenhouse conditions and their narrow host ranges, T. romana and R. donacis are suitable candidates for biological control of this invasive reed grass in North America. [ABSTRACT FROM AUTHOR]

Abstract: Arundo donax (giant reed) is an aggressive invasive weed of riparian habitats throughout the southern half of the United States from California to Maryland. Native to Asia, the species is believed to have been initially introduced into North America from the Mediterranean region although subsequent introductions were from multiple regions. To provide insight into the potential for biological control of A. donax, genetic variation in plants sampled from a wide geographical area in the United States was analyzed using Sequence Related Amplification Polymorphism (SRAP) and transposable element (TE)-based molecular markers. Invasive individuals from 15 states as well as four populations in southern France were genetically fingerprinted using 10 SRAP and 12 TE-based primer combinations. With the exception of simple mutations detected in four plants, A. donax exhibited a single multilocus DNA fingerprint indicating a single genetic clone. The genetic uniformity of invasive A. donax suggests that classical biological control of the species could be successful. A lack of genetic diversity in the invaded range simplifies identification of native source populations to search for natural enemies that could be used as biocontrol agents. [Copyright &y& Elsevier]

Leaf carbon (C) content, leaf nitrogen (N) content, and C:N ratio are especially useful for understanding plant-herbivore interactions and may be important in developing control methods for the invasive riparian plant Arundo donax L. We measured C content, N content, C:N ratio, and chlorophyll index (SPAD 502 reading) for 768 leaves from A. donax collected over a five year period at several locations in California, Nevada, and Texas. Leaf N was more variable than leaf C, and thus we developed a linear regression equation for estimating A. donax leaf N from the leaf chlorophyll index (SPAD reading). When applied to two independent data sets, the equation (leaf N content % = -0.63 + 0.08 × SPAD) produced realistic estimates that matched seasonal and spatial trends reported from a natural A. donax population. Used in conjunction with the handheld SPAD 502 meter, the equation provides a rapid, non-destructive method for estimating A. donax leaf quality. [ABSTRACT FROM AUTHOR]

Perennial grasses display many beneficial attributes as energy crops, and there has been increasing interest in their use in the US and Europe since the mid-1980s. In the US, the Herbaceous Energy Crops Research Program (HECP), funded by the US Department of Energy (DOE), was established in 1984. After evaluating 35 potential herbaceous crops of which 18 were perennial grasses it was concluded that switchgrass (Panicum virgatum) was the native perennial grass which showed the greatest potential. In 1991, the DOE''s Bioenergy Feedstock Development Program (BFDP), which evolved from the HECP, decided to focus research on a “model” crop system and to concentrate research resources on switchgrass, in order to rapidly attain its maximal output as a biomass crop. In Europe, about 20 perennial grasses have been tested and four perennial rhizomatous grasses (PRG), namely miscanthus (Miscanthus spp.), reed canarygrass (Phalaris arundinacea), giant reed (Arundo donax) and switchgrass (Panicum virgatum) were chosen for more extensive research programs. Reed canarygrass and giant reed are grasses with the C3 photosynthetic pathway, and are native to Europe. Miscanthus, which originated in Southeast Asia, and switchgrass, native to North America, are both C4 grasses. These four grasses differ in their ecological/climatic demands, their yield potentials, biomass characteristics and crop management requirements. Efficient production of bioenergy from such perennial grasses requires the choice of the most appropriate grass species for the given ecological/climatic conditions. In temperate and warm regions, C4 grasses outyield C3 grasses due to their more efficient photosynthetic pathway. However, the further north perennial grasses are planted, the more likely cool season grasses are to yield more than warm season grasses. Low winter temperatures and short vegetation periods are major limits to the growth of C4 grasses in northern Europe. With increasing temperatures towards central and southern Europe, the productivity of C4 grasses and therefore their biomass yields and competitiveness increase.Since breeding of and research on perennial rhizomatous grasses (PRG) is comparatively recent, there is still a significant need for further development. Some of the given limitations, like insufficient biomass quality or the need for adaption to certain ecological/climatic zones, may be overcome by breeding varieties especially for biomass production. Furthermore, sure and cost-effective establishment methods for some of the grasses, and effective crop production and harvest methods, have yet to be developed.This review summarizes the experience with selecting perennial grasses for bioenergy production in both the US and Europe, and gives an overview of the characteristics and requirements of the four most investigated perennial rhizomatous grasses; switchgrass, miscanthus, reed canarygrass and giant reed. [Copyright &y& Elsevier]

Focuses on the efforts to control water weed invaders in California. Effect of the aquatic herbicides used by Agricultural Research Service (ARS) researchers on the state's Caulerpa taxifolia infestation; Steps taken by ARS researchers to understand Arundo donax, a giant reed or giant cane invader.

This article discusses the efforts of the U.S. Agricultural Research Service (ARS) to control the spread of Arundo donax, or giant reed, in the U.S. John Goolsby, an entomologist at the Agricultural Research Service, is spearheading the efforts. Goolsby and colleagues have identified four biological controls for the weed, including insects would complement control methods, such as cutting the cane and applying herbicide.