A Potential New Herbicide for Invasive Annual Grass Control on Rangeland

Downy brome (Bromus tectorum L.), a winter annual grass, is considered one of the most invasive non-native rangeland species in the United States. Although glyphosate, imazapic, and rimsulfuron are herbicides commonly recommended to control invasive, annual grasses, their performance is inconsistent and they can injure desirable perennial grasses. Indaziflam is a recently registered cellulose biosynthesis inhibiting herbicide, providing broad-spectrum control of annual grass and broadleaf weeds. Indaziflam is labeled for winter annual grass control in citrus, grape, and tree nut crops and could represent a new mode of action for selective winter annual grass control on rangeland. Three field experiments were conducted to compare indaziflam with imazapic, rimsulfuron, and glyphosate, three herbicides commonly used for downy brome control. Multiple herbicide application timings were evaluated. At all three sites, glyphosate and rimsulfuron provided less downy brome control than indaziflam 1 year after treatment (YAT). Percent downy brome control with imazapic decreased significantly 2 YAT (45-64%) and 3 YAT (10-32%). Across all sites and application timings, indaziflam provided the greatest downy brome control 2 YAT (89-100%) and 3 YAT (83-100%). Indaziflam did not significantly reduce species richness. This study demonstrates that indaziflam can provide extended downy brome control compared with currently used herbicides. © 2016 The Society for Range Management. Published by Elsevier Inc. All rights reserved.The Rangeland Ecology & Management archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact [email protected] for further information

Q fever seroprevalence in metropolitan samples is similar to rural/remote samples in Queensland, Australia

Q fever is a vaccine preventable disease; however, despite this, high notification numbers are still recorded annually in Australia. We investigated the seroprevalence of Coxiella burnetii, the Q fever agent, in a Queensland sample population. Notification data (N = 6425) from 1984-2008 were collated, identifying high risk areas of Q fever exposure. Of these 177 were recorded in children. Serum samples were collected from Queensland and screened using both an immunoflourescence assay at 1:10 dilution and a commercially available ELISA kit. Results were collated based on age, geographical location and sex. From 1988 Queensland samples screened, 103 were identified as Q fever IgG-positive, giving a seroprevalence of 5.2% (95% CI 4.3-6.2%). Seroprevalence in the rural/remote population was 5.3% (95% CI 4.6-6.6%), and the metropolitan Brisbane population, which is considered not at risk, was 5.0% (95% CI 3.7-6.7%). Sixty-three seropositive males and 40 females were identified, along with an increase in seropositivity with increasing age. The seropositivity of children was 1.3% (95% CI 0.7-2.3%) from 844 samples. We have shown that both metropolitan and paediatric populations which are considered low risk of Coxiella exposure have surprisingly high seropositivity. These emerging groups require further investigation and consideration for the introduction of preventive measures

Impacts of Imazapyr and Triclopyr Soil Residues on the Growth of Several Restoration Species

Herbicides are frequently used in natural systems to control invasive plants, but nontarget impacts from persistent soil residues can result in unintended ecosystem effects. Imazapyr and triclopyr are herbicides that are widely used in noncrop areas such as rangelands to manage perennial weeds, especially woody species such as tamarisk (saltcedar). Due to widespread environmental and anthropogenic changes in the American southwest, tamarisk, which is commonly thought to co-occur only with riparian plants, is increasingly being found in communities of upland rangeland species. Using an in vitro study combined with high-performance liquid chromatography (HPLC) analyses, imazapyr and triclopyr degradation rates were determined in six Colorado soils. In addition, the relative sensitivity of desirable species to the two herbicides was determined in a field dose response study. Exponential decay models estimated that triclopyr degradation (half-lives of 5-16 days) was 20 times more rapid than imazapyr degradation (half-lives of 82-268 days). All species tested were sensitive to imazapyr residues, but the degree of sensitivity was strongly dependent on soil properties. Sensitive species (alkali sacaton and western wheatgrass) were tolerant of imazapyr residues in some soils 20-23 months after applications. Relatively insensitive species (slender wheatgrass) were tolerant of imazapyr residues in the same soils 10 months after applications. American licorice was sensitive to triclopyr residues up to 89 days after applications, and several grasses (including sideoats grama) showed minor sensitivity. Our study indicates that there is an interaction between the spatial variability in herbicide degradation driven by edaphic properties and the sensitivity of plants to a herbicide, which could be exploited by management practitioners to aid in site rehabilitation. Specifically, managers could stagger planting of species temporally on the basis of their sensitivity to herbicide residues or could target areas of treated sites for planting that are known to have soil types facilitating relatively rapid herbicide degradation. © 2016 The Society for Range Management. Published by Elsevier Inc. All rights reserved.The Rangeland Ecology & Management archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact [email protected] for further information

Seed Bank Depletion: The Key to Long-Term Downy Brome (Bromus tectorum L.) Management

Invasive winter annual grasses such as downy brome (Bromus tectorum L.) are a threat to native ecosystems throughout the United States. Downy brome is able to exploit moisture and nutrients throughout the fall and early spring before native plants break dormancy. This results in decreased native species abundance and development of monotypic downy brome stands. Short-termdowny brome management has been shown to be effective; however, the soil seed reserve has often been overlooked, although it's the mechanismresponsible for rapid reestablishment. This field study was conducted at two sites in Colorado to evaluate the longevity of the downy brome soil seed reserve and its implications on long-termdowny brome control. Glyphosate plus adjuvant applications were made for 0, 1, 2, 3, 4, or 5 consecutive years. Downy brome and perennial grass biomass harvests were conducted yearly to determine changes in species composition. In addition, soil cores were collected to evaluate the yearly variation and depletion of the downy brome soil seed bank in response to consecutive glyphosate applications. We found that 1-3 yr of consecutive glyphosate treatments were insufficient to deplete the downy bromesoil seed bank. Downy brome biomass and the soil seed bank recoveredwithin 1-2 yr after glyphosate treatmentswere terminated; however, 4 and 5 consecutive yr of glyphosate applications were sufficient to control downy brome through depletion of the soil seed bank. Managing downy brome for 4-5 consecutive yr resulted in a 4- to 9-fold increase in perennial grass biomass. These data suggest that long-term management of downy brome is dependent on eliminating the soil seed bank using a multiyear approach. © 2017 The Society for Range Management. Published by Elsevier Inc. All rights reserved.The Rangeland Ecology & Management archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact [email protected] for further information

Genetic diversity among proso millet (Panicum miliaceum) biotypes assessed by AFLP technique.

A técnica de AFLP (Amplified Fragment Length Polymorphism) foi empregada para acessar a diversidade genética entre três biótipos domesticados e nove biótipos selvagens de proso millet dos Estados Unidos e do Canadá. Oito combinações de primers detectaram 39 fragmentos polimórficos de DNA, e a estimativa da distância genética entre os biótipos variou de 0,02 a 0,04. Colorado-Weld County de sementes pretas e Wyoming-Platte County foram os biótipos mais distintos de acordo com o índice de dissimilaridade. A análise de cluster por UPGMA revelou dois grupos distintos de proso millet mas sem nenhuma relação geográfica. Seis biótipos selvagens que exibiam algumas características de plantas cultivadas foram agrupados juntamente com os biótipos domesticados de proso millet, enquanto os três fenótipos tipicamente selvagens formaram outro grupo distinto por marcadores AFLP.200

Potential Animal and Environmental Sources of Q Fever Infection for Humans in Queensland

Q fever is a vaccine-preventable disease; despite this, high annual notification numbers are still recorded in Australia. We have previously shown seroprevalence in Queensland metropolitan regions is approaching that of rural areas. This study investigated the presence of nucleic acid from Coxiella burnetii, the agent responsible for Q fever, in a number of animal and environmental samples collected throughout Queensland, to identify potential sources of human infection. Samples were collected from 129 geographical locations and included urine, faeces and whole blood from 22 different animal species; 45 ticks were removed from two species, canines and possums; 151 soil samples; 72 atmospheric dust samples collected from two locations and 50 dust swabs collected from domestic vacuum cleaners. PCR testing was performed targeting the IS1111 and COM1 genes for the specific detection of C.burnetii DNA. There were 85 detections from 1318 animal samples, giving a detection rate for each sample type ranging from 2.1 to 6.8%. Equine samples produced a detection rate of 11.9%, whilst feline and canine samples showed detection rates of 7.8% and 5.2%, respectively. Native animals had varying detection rates: pooled urines from flying foxes had 7.8%, whilst koalas had 5.1%, and 6.7% of ticks screened were positive. The soil and dust samples showed the presence of C.burnetii DNA ranging from 2.0 to 6.9%, respectively. These data show that specimens from a variety of animal species and the general environment provide a number of potential sources for C.burnetii infections of humans living in Queensland. These previously unrecognized sources may account for the high seroprevalence rates seen in putative low-risk communities, including Q fever patients with no direct animal contact and those subjects living in a low-risk urban environment

Progression of coronary atherosclerosis in patients without standard modifiable risk factors

Background and aims: The outcome of patients with clinical coronary artery disease despite traditional risk factors is poorly understood. Methods: Clinical characteristics and plaque burden on serial intravascular ultrasonography were compared in patients without (n ¼ 165) and with (n ¼ 492) standard modifiable risk factors after matching on age, sex and use of statins from a database of 5823 patients participating in clinical trials of anti-atherosclerotic therapies. Results: Patients without standard modifiable risk factors had lower baseline systolic blood pressure (118 ± 12 vs. 129 ± 17 mmHg, p < 0.001), low-density lipoprotein cholesterol (87 ± 21 vs. 104 ± 34 mg/dl, p < 0.001), triglycerides [106 vs. 136 mg/dl, p < 0.001)] and C-reactive protein [1.5 vs. 2.1 mg/l, p ¼ 0.001]. At baseline, patients without modifiable risk factors had a lower percent atheroma volume (35.7 ± 8.6 vs. 38 ± 8.8%, p ¼ 0.004) and total atheroma volume (174.7 ± 80 vs. 190.9 ± 84 mm³, p ¼ 0.03) and less images with calcification (22.2 vs. 26.5%, p ¼ 0.025). The use of aspirin and statin prior to and during the trials was similar. The use of ACE inhibitors and beta blockers was lower in the no risk factor group prior to and during the trials. The change in percent atheroma volume (-0.2 ± 2.8 vs. -0.1 ± 3.6%, p ¼ 0.71), total atheroma volume (-5.5 ± 23.4 vs. -3.8 ± 22.7 mm³, p ¼ 0.42), and the percentage of patients demonstrating any degree of progression (50.9% vs 45.1%, p ¼ 0.20) were similar in those without and with standard modifiable risk factors, respectively. Conclusion: Patients who develop clinical coronary atherosclerosis without standard modifiable risk factors have similar rates of plaque progression to those with traditional risk factors.Jawad Mazhar, Gemma Figtree, Stephen T. Vernon, Keyvan Karimi Galougahi, Julie Carlo, Steven E. Nissen, Stephen J. Nicholl