Cut Stump Research Articles

Novel basal bark and cut stump herbicide treatments for Brazilian peppertree (Schinus terebinthifolia) management

AbstractBrazilian peppertree (Schinus terebinthifolia Raddi) is an aggressive shrub that infests more than 280,000 ha in Florida. Individual plant treatments (IPT), including basal bark and cut stump application with triclopyr butoxyethylester and triethylamine formulations, respectively, have been used for decades. While they are both effective, resprouting can occur, which requires retreatment for control. Recent research on other woody invasive plants has indicated additional non-crop herbicides used in natural areas can be effective with these IPT techniques and therefore warrant testing on S. terebinthifolia. In 2018 and 2019, basal bark and cut stump studies were conducted at Cape Canaveral Air Force Station in natural areas infested with S. terebinthifolia. In the basal bark application studies, we found aminocyclopyrachlor applied at 12 and 24 g L−1 and triclopyr acid applied at 34 and 69 g L−1 each provided 100% defoliation of multistemmed S. terebinthifolia individuals with a mean root collar diameter up to 20.2 cm at 360 d after treatment (DAT). These were not different from triclopyr ester applied at 96 g L−1. Imazamox applied at 30 g L−1 resulted in 86% defoliation at 360 DAT. However, we observed formulation incompatibility when imazamox was mixed with basal bark oil which may limit its utility. In cut stump studies, we found aminocyclopyrachlor and aminopyralid each individually applied at 6, 12, and 24 g L−1, resulted in stump mortality that was not different from the commercial standard triclopyr amine applied at 180 g L−1. Similar results were found for a triclopyr acid formulation applied at 86 and 172 g L−1 and imazamox applied at 60 g L−1. For both treatment techniques, we found that alternative treatments provided control at lower herbicide concentrations than triclopyr ester and amine commercial standards. These results advance our understanding of IPT and expand access to additional effective herbicide options for S. terebinthifolia management.

Susceptibility of winter cut red pine (P. resinosa) stumps to heterobasidion root disease (HRD) infection

Heterobasidion root disease (HRD), a destructive disease of conifers, is a growing management concern. Infection by HRD fungus ( Heterobasidion irregulare) most often occurs when spores, usually produced when temperature is between 5 and 32 °C, land and germinate on freshly cut surfaces. Older stump surfaces are generally unsuitable for colonization, likely due to changes in chemical and physical properties of wood and competitor fungi that limit HRD infection. Stump protectants are effective but not used or recommended in subfreezing temperatures during winter when spores are less common. This study evaluated the potential for older cut stump infection following snowmelt in spring via inoculation of disks collected 7 weeks following initial thinning and exposed to extensive subfreezing temperatures. We found that a surprising number of disks (40%) were successfully colonized with H. irregulare. More research on potential for winter cut conifer HRD infection is warranted as are steps to limit this potential.

Experimental prosopis management practices and grassland restoration in three Eastern African countries

Woody species have been introduced in many parts of the world to provide economic benefits, but some of those species are now among the worst invaders, causing widespread economic and environmental damage. Management of woody species to restore original ecosystem services, such as biodiverse grassland that can provide fodder and sequester carbon, are needed to limit the impacts of alien species. However, the best management methods, i.e., the most economically efficient and effective way to remove trees and the most effective way to restore or rehabilitate the cleared land, are not developed for many species. In Eastern Africa, prosopis (Prosopis julifora) has invaded large areas of savanna and grassland, thereby affecting, among other things, fodder and water for livestock, access to dry season grazing lands and ultimately pastoral livelihoods. We tested three prosopis treatments (manual uprooting and cut stump and basal bark herbicide application) in combination with three incremental restoration interventions (divots, divots + mulching, divots + mulching + grass seed sowing). The three-year study was replicated in Ethiopia (Afar National Regional State), Kenya (Baringo county) and Tanzania (Moshi district). Prosopis survival and vegetation development, both diversity and biomass, were recorded. The prosopis treatments were all highly effective (between 85 and 100% tree mortality in almost all cases), but the two treatments that involved the complete removal of the aboveground biomass (manual and cut stump) yielded a more productive and more diverse vegetation than the treatment that killed the trees standing (basal bark). Compared to the effect of prosopis removal, the effect of restoration interventions on vegetation composition was small, indicating that most species re-established from the soil seed bank. The results show that it is possible to restore land previously invaded by prosopis. Despite the different rates of vegetation establishment and variation in species composition, the restoration interventions resulted in vegetation that in some cases contained a substantial fraction of perennial grasses. The method chosen to control prosopis depends on the availability of resources, including herbicides, and the need to remove rootstocks if the intention is to plant crops.

Herbicide control of swamp titi (Cyrilla racemiflora) in restoration of ephemeral wetlands

Swamp titi (Cyrilla racemiflora L.) is a vigorous native shrub or small tree found in poorly drained areas of the southeastern U.S. Coastal Plain. In the absence of fire, it creates dense thickets that prevent herbaceous groundcover in ephemeral wetlands, degrading habitat for uncommon and endangered amphibians and other genera. In our study, aquatic herbicides and methods of application were examined at two forests in north Florida for restoration of ephemeral wetland habitat to benefit wetland‐breeding amphibians. Glyphosate, imazapyr, and combinations of glyphosate and imazapyr were tested in four study protocols that included an operational standard (triclopyr), treatment method control, and untreated control where appropriate. Results of foliar protocols (targeting rootstocks less than 1.5 m tall) demonstrated that glyphosate provided better titi control than imazapyr (average of 79% vs. 12% mortality), there was no strong improvement with the addition of imazapyr to glyphosate (84% mortality), glyphosate treatments had titi mortality as high or higher than the triclopyr operational treatment (57% mortality), and that methylated seed oil surfactant improved glyphosate efficacy but might have been antagonistic for combination treatments. Glyphosate and imazapyr cut stump treatments did not provide higher efficacy than the triclopyr standard treatment (60% mortality). Cut stem treatments (targeting rootstocks greater than 1.5 m tall) provided the highest level of control averaging 97, 90, 97, and 80% mortality for glyphosate, imazapyr, combination treatments, and triclopyr standard, respectively. Only directed foliar sprays reduced total groundcover and graminoid cover, with triclopyr treatment giving the least reduction of desired herbaceous groundcover.

Reduced hack and squirt treatment with aminocyclopyrachlor and aminopyralid for invasive shrub control

AbstractInvasive shrubs often present extremely difficult challenges for individual plant treatment approaches due to multiple basal stems with complex branching patterns. Basal bark and cut stump individual plant treatments have been the standard methods for managing large-statured shrubs, while hack and squirt has been disregarded as operationally too difficult. However, hack and squirt is a more discriminant treatment technique that may lead to a reduction in herbicide use. Here, we evaluated the speed, herbicide use, and performance of a reduced hack and squirt approach using single hacks per stem injected with 0.5 ml of either aminocyclopyrachlor (240 g L−1) or aminopyralid (240 g L−1) against conventional low-volume basal bark treatment with triclopyr ester (96 g L−1) and cut stump treatment with triclopyr amine (180 g L−1). The experiments were conducted on three subtropical shrub species: Eugenia uniflora, Lagerstroemia indica, and Schinus terebinthifolia. Across species, we found the reduced hack and squirt approach resulted in comparable treatment efficacy to basal bark and cut stump treatment, was faster than cut stump treatment, and used less herbicide and carrier than basal bark treatment. A single hack per stem is a significant shift for hack and squirt treatment, which typically employs a narrow or continuous spacing of hacks around the entire circumference of each stem. Future work should seek to clarify the applicability of this approach over a wide range of invasive shrubs.

Current status of the invasive shrub Berberis julianae C.K. Schneid. (Berberidaceae) in Golden Gate Highlands National Park (Free State Province, South Africa)

• Berberis julianae is an alien invasive evergreen shrub in South Africa. • Surveys were conducted to determine effectiveness of previous control interventions. • Cut-stump and chemical treatment were effective for controlling adult plants. • Seedling numbers increased significantly over 6 years after initial control. • Follow-up control should be implemented immediately to stop spread. Berberis julianae commonly known as Wintergreen barberry or Chinese barberry, is an evergreen shrub species native to China which has been introduced into South Africa and has become invasive in a few locations. In 2015, management measures were taken in an attempt a control a population in Golden Gate Highlands National Park (GGHNP) in the Free State Province. After assessing the plant demographics within the park, the following management options were implemented: cut stump treatments of larger shrubs, foliar spray herbicide applications and hand pulling of seedlings. It was recommended that follow-up research be conducted to check if control measures were successful or not. This study aimed to map and determine the current distribution of B. julianae in GGHNP and to investigate the change in B. julianae population demographics to that recorded previously. The study showed that the number of seedlings had multiplied from 6 seedlings in 2014 to 588 in 2020, whereas the number of mature shrubs had decreased in the same time period. In conclusion, the control measures conducted have been successful in reducing the adult population, however, additional follow-up control of seedlings is urgently required to stop further spread.

Vegetation Pattern and Regeneration Dynamics of the Progressively Declining Monotheca buxifolia Forests in Pakistan: Implications for Conservation

Monotheca buxifolia (Falc.) A. DC., a wild edible fruit-yielding tree species, has economic and ecological importance, yet there is a lack of studies concerning its distribution pattern and regeneration dynamics at a larger-scale. This study aims to produce the first country-level classification of Monotheca forests based on their unique floristic composition and influential abiotic factors, besides their natural regeneration dynamics, across the environmentally diverse landscapes in Pakistan. For this purpose, floristic inventory was carried out in 440 plots where environmental variables, stand dendrometric characteristics and woody-species regeneration were recorded. During this survey, 3789 individuals of 27 woody tree species belonging to 25 genera and 22 families were sampled. These native and exotic tree species were mostly dicot (73%) with predominately mega-phanerophytic (88%) lifeforms, which largely reflect strong chorological differentiation and distinct linkage (55%) to the Sino-Japanese phytogeographical region. M. buxifolia and co-occurring species exhibiting similar environmental affinities were grouped into four ecologically distinct communities by Ward’s cluster analysis. Ordinations further highlight the special effects of topographic and edaphic factors besides anthropogenic interference on the sampled plots. Generally, Monotheca stands were moderately dense, with the average density varying considerably, ranging from 296 to 325 individuals/ha, with basal area ranging from 41.26 to 93.35 m2 ha−1. In the understory stratum, natural regeneration of Monotheca was mostly scant and mainly covered by Dodonaea shrubs. Size class structure of the dominant species shows pronounced effect of anthropogenic intervention as reflected by the presence of fewer individuals of juveniles and larger trees. Overall, the cut stump frequency was higher at juvenile and mature stages, which may be attributed to over-harvesting and extraction of fuelwood apart from the adverse effect of climate change in the region. We concluded that both topographic and edaphic factors coupled with biotic interventions are more influential in the distribution and persistence of M. buxifolia and co-occurring woody species and might be considered in its restoration and conservation. Thus, we recommend an urgent management plan to favor Monotheca regeneration for allowing the renewal of these rapidly declining remnant stands in Pakistan.

The effect of a novel herbicide adjuvant in treating Amur honeysuckle (Lonicera maackii)

AbstractInvasive woody perennials pose an immense threat to the diversity and function of many ecosystems, including forests in the eastern United States. While herbicide treatments have proven effective in controlling many plant invasions, there is considerable interest in the refinement of herbicide prescriptions to improve efficacy and prevent non-target damage. Adjuvants are widely utilized to improve herbicide efficacy, but research on novel adjuvants is often lacking. Furthermore, adjuvant research has generally focused on enhancement of foliar herbicide absorption, and few studies focus on adjuvant utility for other herbicide delivery techniques such as cut stump treatments. We evaluated 2XL—a cocktail of cellulase enzymes derived from fungi—as a potential herbicide adjuvant for use with glyphosate applied in a cut stump treatment due to its ability to degrade a key component of cell walls. We conducted a field experiment using the cut stump method of treatment (cut surface treated with herbicide) on a problematic invasive shrub, Amur honeysuckle [Lonicera maackii (Rupr.) Herder]. We tested combinations of three concentrations of 2XL with five concentrations of glyphosate and hypothesized that low concentrations of glyphosate combined with 2XL would be as effective in limiting the resprouting of L. maackii as higher concentrations of glyphosate without the enzymes. Our results indicated that 2XL did not improve glyphosate efficacy for reducing the number of resprouting stems or the length of the longest resprouting stem within the same or following year as treatment. Limited data indicated the combination of 2XL and glyphosate applied at 30 g L−1 slightly increased resprouting in the year following treatment. While 2XL did not improve glyphosate efficacy, our results showed effective control of L. maackii at the lowest concentration of glyphosate tested (30 g L−1), suggesting that concentrations lower than those typically applied may be effective in controlling L. maackii within parameters similar to those tested here.

A long-term survivor after radical surgery in early childhood for biliary tract cancer associated with congenital biliary dilatation despite a positive margin for epithelial carcinoma

We previously reported the case of a three-year-old patient with extrahepatic bile-duct cancer with congenital biliary dilatation (CBD), representing the youngest patient reported thus far with this disease. After surgery, a histopathologic examination confirmed well-differentiated adenocarcinoma with fibromuscular invasion and vascular infiltration, and the cut stump was positive for carcinoma -in-situ (CIS) at both the hepatic and distal margin of the bile duct. Since the patient was young, no additional therapy was selected after the surgery, and we have carefully followed the patient for more than 10 years with imaging and hematological examinations. To date, no abnormalities have been observed in his liver function, CA19-9 levels, or MRCP findings, and he has survived without recurrence for over 13 years since the surgery. A molecular biological reexamination of the initial resected specimen revealed that the cancer cells had no mutations in Kras codon 12, 13, 59, 61, 117, or 146 or Braf. The course of this case demonstrated the validity of surgery for pediatric biliary tract cancer associated with CBD. Furthermore, it was revealed that the positive resection margin in CIS of cholangiocarcinoma does not always recur even after a long period of time. However, the possibilities of late term recurrence of the disease and metachronous carcinogenesis at residual biliary tract still remain, so lifelong follow-up will be required for the patient.

A locally advanced pancreatic body cancer presenting common bile duct invasion resected via distal pancreatectomy after gemcitabine plus nab-paclitaxel chemotherapy: A case report.

IntroductionThe locally advanced pancreatic cancer has been steadily recognized as a potentially curable disease by a combination of chemotherapy and surgery. The remarkable effect of advanced chemotherapy would help surgeons do a function-preserving operation for advanced pancreatic cancer.Presentation of caseA 73-year-old woman presenting with obstructive jaundice was diagnosed to have a 3-cm pancreatic body cancer invading the celiac axis (CA), superior mesenteric artery (SMA), portal/splenic vein confluence, and the common bile duct (CBD). A plastic internal stent tube was placed endoscopically. After 11 cycles (231 days) of a weekly doublet chemotherapy with 1000 mg/m2 of gemcitabine and 125 mg/m2 of albumin-bound paclitaxel, the tumor shrunk based on imaging done every four months during chemotherapy, with residual periarterial high-density area around CA and proximal SMA and the patient was referred for surgery. During the operation, the absence of cancer cells was confirmed at (1) the origin of the proper hepatic artery, gastroduodenal artery and the left gastric artery, and (2) pancreatic cut stump along the right border of the portal vein; thus, distal pancreatectomy with coeliac axis resection was done. The patient had postoperative adjuvant chemotherapy with 100 mg/day of tegafur/gimeracil/oteracil for half a year and is currently alive and well, without signs of recurrence and diabetes mellitus a year after surgery.DiscussionAlthough surgical techniques aimed at local radicality are important, especially for conversion surgery for locally advanced pancreatic cancer, surgeons should consider the balance between radicality, safety, and functional preservation of surgery.

Novel Encapsulated Herbicide Delivery Mechanism: Its Efficacy in Mimosa Bush (Vachellia farnesiana) Control.

Mimosa bush (Vachellia farnesiana) is an invasive woody weed widely distributed in Australia. While it can be controlled using several mechanical and chemical techniques, this study evaluated a novel herbicide delivery mechanism that minimizes the risk of spray drift and potential non-target damage. This method, developed by Bioherbicides Australia, involves the implantation of encapsulated granular herbicides into the stem of intact plants or into the stump after cutting off plants close to ground level (cut stumps). Trials were implemented near Moree (New South Wales, Australia) on intact (two experimental runs) plants and cut stumped (two experimental runs) plants. For each trial, an untreated control plus the conventional basal bark application of a liquid formulation of triclopyr + picloram mixed with diesel was included for comparison. Encapsulated glyphosate, aminopyralid + metsulfuron-methyl, hexazinone and clopyralid were also tested in all trials. In addition, encapsulated triclopyr + picloram, and metsulfuron-methyl were included in one of the intact plant trials. Aminopyralid + metsulfuron-methyl was consistently most effective on cut stump and intact plants, whilst clopyralid provided highest mortality when applied to cut stumps and single-stemmed intact plants. Particularly for multi-stemmed intact plants, clopyralid should be applied to each stem. Overall, the highest efficacy was achieved on single stemmed plants, but with further refinement of the technique, it should be possible to achieve similar results for multi-stemmed individuals. This method resulted in a reduction in the use of herbicide and environmental contamination while significantly improving speed of treatment.

Output variation of trigger-pump sprayers used for individual plant treatments

AbstractIndividual plant treatment (IPT) techniques (e.g., basal bark, cut stump, hack and squirt) are used for woody invasive plant management and often rely on small trigger-pump spray bottles as an economical and efficient way to deliver a herbicide to the target species. Worldwide, plastic suppliers produce many models and designs with a wide range of uses, including pesticide application. However, spray bottle performance has rarely been examined in relation to IPT techniques for operational invasive plant management. We tested 10 commonly available spray bottles for trigger output and variation over repeated strokes. We also examined sustained trigger sprayer performance over a 6-wk period for spray bottles containing water or basal oil carriers blended with amine and ester formulations of triclopyr, respectively. In the first study, we found significant differences in spray output per stroke between almost every bottle tested. Almost all spray bottle brands yielded outputs greater than 1.0 ml per stroke, which exceeds the maximum application amount specified for hack and squirt. Several bottles produced an output of greater than 2.5 ml per stroke. In the second study, the output per stroke was reduced for basal oil mixes, with significant reductions measured for two brands by 21 d and for all three brands tested by 42 d after mixing. These results indicate that consumer-grade trigger sprayers are likely to depreciate rapidly with routine operational use without proper hygiene maintenance. Even then it is likely that these application devices may need to be replaced several times annually. Trigger-pump spray bottles are an economical and practical solution for remote field operations and volunteer weed control activities. These sprayers are most suitable for spray-to-wet techniques such as basal bark and cut-surface treatments but may potentially be less suited for hack and squirt application, which often requires sub-milliliter precision.

Herbicide Options to Control Naturalised Infestations of Cereus uruguayanus in Rangeland Environments of Australia.

While there are many high profile Opuntioid cactus species invading rangeland environments in Australia, Cereus uruguayanus Ritt. ex Kiesl. has also naturalised and formed large and dense infestations at several locations. With no herbicides registered for control of C. uruguayanus in Australia, the primary aim of this study was to identify effective herbicides to control it using a range of techniques. This involved a large screening trial of twelve herbicides and four techniques, followed by a rate refinement trial for cut stump applications and another to test residual herbicides. Despite most treatments (except monosodium methylarsonate (MSMA)) taking a long time to kill plants, at least one effective herbicide was identified for basal bark (triclopyr/picloram), cut stump (aminopyralid/metsulfuron-methyl, glyphosate, metsulfuron-methyl, triclopyr/picloram, triclopyr/picloram/aminopyralid), stem injection (glyphosate, MSMA, triclopyr/picloram/aminopyralid) and foliar applications (aminopyralid/metsulfuron-methyl, MSMA, triclopyr, triclopyr/picloram/aminopyralid) due to their ability to kill both small and large plants. Ground application of residual herbicides was less conclusive with neither hexazinone nor tebuthiuron causing adequate mortality at the rates applied. This study has identified effective herbicides for the control of C. uruguayanus using several techniques, but further research is needed to refine herbicide rates and develop integrated management strategies for a range of situations and infestation sizes and densities.

Biology, distribution and management of the invasive Jatropha gossypiifolia (Bellyache bush): A global review of current and future management challenges and research gaps

AbstractJatropha gossypiifolia (Bellyache bush) is an evergreen, perennial, invasive woody shrub that globally threatens agricultural and native landscapes. The species is native to North and South America, but is currently found in over 52 countries; in many of these countries, it is listed as invasive, due to its aggressive and competitive growth. These behaviour traits are characterised by its quick flowering and seed production that make the species difficult to contain and control, as it forms dense monocultures and restricts the growth of many native and pastoral species through aggressive competition for resources, such as soil moisture and nutrients. Infestation by J. gossypiifolia results in a loss of biodiversity in the affected area and disrupts the maintenance of sustainable land systems. It has been reported that J. gossypiifolia is used in many countries as a traditional medicine to treat a range of diseases, illnesses and injuries. However, despite these claims of its positive use, J. gossypiifolia leaves, seeds and stems are highly toxic to grazing animals and humans, leading to disruption and significant increases in the cost of agricultural production through the loss of production and the instituting of necessary management efforts. Around the world, there have been various attempts to control J. gossypiifolia, but these have widely varied in their success. The most common and successful treatments to control J. gossypiifolia, including herbicide application (cut stump application), fire management and mechanical control; however, when each is applied as a single treatment, long‐term success is often limited. Consequently, this review explores the biology and distribution of J. gossypiifolia, together with previous and current control attempts, and synthesises potentially useful approaches to control this noxious weed, whilst identifying areas of future research to improve effective and long‐term sustainable management strategies for this noxious species.

An Assessment of Forest Structure, Regeneration Status and the Impact of Human Disturbance in Panchase Protected Forest, Nepal

Vegetation study is crucial for the biophysical environment and ecosystem balance. Both qualitative and quantitative assessments of the vegetation can give complete picture of the forest ecosystem. In this study, quantitative characteristics of Panchase Protected Forest in Kaski district were analyzed. The study was focused on the structural characteristics of forest stand, its regeneration pattern along altitudinal gradients, and human impacts on vegetation structure. Density, basal area, frequency, and Importance Value Index (IVI) were used to assess the structural characteristics of forest; Density-Diameter (DD) curve and seedling/sapling/tree density relation were used to assess the regeneration status. Counting the number of lopping and cut stumps and quantifying fuelwood consumption pattern of the village were used to assess human disturbance. The vegetation survey showed 21, 17 and 14 species of trees, saplings, and seedlings, respectively. Daphniphyllum himalense was the most dominant species followed by Quercus lamellosa. DD curve showed reverse J-shaped structure indicating sustainable regeneration. Daphniphyllum himalense and Alnus nepalensis were major species of trees consumed as fuelwood and average annual fuelwood consumption was 2083.79 tons. Density of lopped trees and cut stump was in decreasing trend along with elevation. Species richness was higher in moderately disturbed sites. This study has significant implications for protected forest management and biodiversity conservation in Nepal.

Efficacy of five herbicide treatments for control ofPyrus calleryana

AbstractCallery pear (Pyrus calleryanaDecne.) is rapidly spreading in the United States, gaining attention in the last two decades as a serious invasive pest. Recommended control methods include foliar, basal bark, cut stump, and hack-and-squirt application of herbicides, but there are few published studies with replicated data on efficacy. Four readily available herbicidal active ingredients and a combination of two active ingredients were tested for control efficacy againstP. calleryanain old-field areas and loblolly pine (Pinus taedaL.) understory. Basal bark applications (triclopyr, triclopyr + aminopyralid), foliar applications (glyphosate, imazapyr), and a soil application (hexazinone) effectively killedP. calleryanawith the exception of hexazinone at one site, where rainfall may not have been optimal. Foliar application of glyphosate provided the most consistent control. Our results demonstrate efficacy of registered herbicide formulations forP. calleryanacontrol in two geographic locations and two habitat types. The need for development of integrated pest management programs forP. calleryanais discussed.

Control of Ailanthus altissima using cut stump and basal bark herbicide applications in an eighteenth‐century fortress

AbstractThe Cittadella di Alessandria (Italy) is a military fortification that was built in the 18th century. The site has recently been abandoned and is now colonised by weeds, including the invasive Ailanthus altissima. The aim of the study was to compare the efficacy of different herbicides (glyphosate, a mixture of aminopyralid + fluroxypyr and triclopyr + fluroxypyr) applied to cut stumps or to the basal bark of A. altissima. For the cut stump application, plants were first cut at the base and then immediately sprayed and for the basal bark application, the lower 50 cm of the plants was sprayed with the herbicides; untreated cut plants were used as a control, for comparison. Two runs per study were carried out (in summer 2015 and in spring 2016). Efficacy was assessed up to 2018 by counting the resprouts and their height in the cut stump application and, for the basal bark treatment, by measuring the variation in the plant circumference after treatment. The cut stump treatment carried out in summer greatly reduced the number of resprouts, compared to the spring treatment, to less than one sprout per plant when aminopyralid + fluroxypyr was used, and its efficacy lasted for about two years. The basal bark treatment did not control the species, but lower levels of variation in circumference and greater mortality were detected in plants treated with aminopyralid + fluroxypyr. Considering the high level of infestation of the site and the high risk of plant resprouting, repeated cut stump treatments with aminopyralid + fluroxypyr would be preferable to eradicate this invasive species.

Integrating conventional management methods with biological control for enhanced Tamarix management

AbstractInvasive shrubs like Tamarix spp. are ecological and economic threats in the U.S. Southwest and West, as they displace native vegetation and require innovative management approaches. Tamarix control typically consists of chemical and mechanical removal, but these methods may have negative ecological and economic impacts. Tamarisk leaf beetles (Diorhabda spp.) released for biocontrol are becoming increasingly established within Western river systems and can provide additional control. Previous Diorhabda research studied integration of beetle herbivory with fire and with mechanical management methods and herbicide application (e.g., cut stump), but little research has been conducted on integration with mowing and foliar herbicide application, which cause minimal soil disturbance. At Caballo Reservoir in southern New Mexico, we addressed the question: “How does Tamarix respond to chemical and mechanical control when Diorhabda is well established at a site?” A field experiment was conducted by integrating mowing and foliar imazapyr herbicide at standard (3.6 g ae L−1 [0.75% v/v] and low (1.2 g ae L−1 [0.25% v/v]) rates with herbivory. Treatments were replicated five times at two sites—a dry site and a seasonally flooded site. Beetles and larvae were counted and green foliage was measured over 2 yr. Mowing and full herbicide rates reduced green foliage and limited regrowth compared with low herbicide rate and beetles alone. Integrating conventional management such as mowing and herbicide with biocontrol could improve Tamarix management by providing stresses in addition to herbivory alone.

Professional Applicator's Guide to Herbicides for Melaleuca Control

Herbicides are used for integrated management of melaleuca (Melaleuca quinquenervia) trees to kill existing trees. Products with the herbicide active ingredients glyphosate, imazapyr, triclopyr, and hexazinone are used depending on the application method and other factors, including presence of non-target vegetation in the application area. Four application methods, foliar, frill-and-girdle, cut stump, and basal (applied to the soil) are used depending on extent of the population and other factors. Helicopter, truck, or all terrain vehicle (atv)-mounted sprayers, backpack sprayers, and hand-held spray bottles, and dropper bottles are used for application of herbicide. Various adjuvants may be added to the spray mixture to aid or modify the action of the herbicide or the physical characteristics of the mixture. A marker dye is often added to the spray solution to help visualize where herbicide is applied. This document is SS-AGR-258, one of a series of the Agronomy Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Original publication date October 2005.

Linking Herbicide Dissipation to Soil Ecological Risk along Transmission Rights-of-Way in the Yukon Territory, Canada.

In the Yukon Territory, transmission rights-of-way (ROWs) are managed using brushing and mowing techniques alone. When cut, target species such as Michx. and spp. grow rapidly shortening maintenance cycles. Long-term vegetation control may be improved by integrating herbicide application. However, prior to implementation, the dissipation and toxicity of herbicides in northern latitudes needed to be assessed. The dissipation of Garlon XRT (triclopyr) and Arsenal Powerline (imazapyr) in soils was assessed at five ROW locations representative of the main ecoregion types where ROWs occur within the Yukon Territory. Soils from four sites were collected at 1, 30, and 365 d after treatment to determine persistence of herbicides for each of three application methods (backpack spraying, cut stump, and point injection). Increased sampling intervals were added to better determine the dissipation rate of each herbicide in Yukon Territory soils. Soil dissipation data were linked to a series of standardized toxicity tests, including three soil invertebrates (, , and ). Additionally, the dissipation of both herbicides from the target species L. was assessed at one site. Herbicide residues persisted in soils for longer than 365 d after treatment and longer than 30 d after treatment in . However, concentrations were below the concentration that would affect 25% of the invertebrate species tested. Weight of evidence and toxic exposure ratios were used to characterize the risks associated with herbicide application in northern latitudes and provided both qualitative and quantitative means to communicate the results to the public.