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Invasive species, including more than three dozen Asteraceae, such as Solidago canadensis, Leucanthemum vulgare, Senecio inaequidens etc, pose serious threat to ecosystem health. Arbuscular mycorrhizal symbiosis is a key factor for distribution of invasive species of some Asteraceae tribes, including Astereae, Anthemideae, Senecioneae, Gnaphalieae, Cardueae, and Cichorieae. The formation of invasion-friendly plant communities has occurred through increasing nutrient and water availability, hormonal regulation, production of bioactive compounds, and mycorrhiza-induced resistance of host plants. Native species are displaced through the influence on soil microbiota, mycorrhizal and nutrient status of neighboring plants, and several other parameters. Allelopathic influences and symbiotic interactions with bacteria and other fungi can inhibit these processes. Understanding the mycorrhizal status of invasive weeds, in our opinion, is a necessary condition for their successful control.

Invasive weeds of the Asteraceae family are widespread in the world. Arbuscular mycorrhiza (AM) is one of the main factors contributing to the successful distribution of these species that is most clearly manifested in the subfamily Asteroideae. The benefits of plant-AMF symbiosis are most significant under unfavorable biotic and abiotic conditions. The specificity of the relationship between arbuscular mycorrhizal fungi (AMF) communities and plants and is determined at the presymbiotic stage. The AMF colonization level is higher in invasive species than in native ones, but AMF communities associated with Asteraceae invasive species are less diverse. AMF communities of Asteraceae invaders often include fewer common species (e.g., species belonging to Diversisporales). Invaders also reduce native AMF species richness in new areas. Arbuscular mycorrhizal fungi can form mycorrhizal networks that allow the redistribution of nutrients in plant communities. The most significant influence of AMF associated with invasive Asteraceae plants is seen in the formation of soil and rhizosphere microbiota, including the suppression of beneficial soil bacteria and fungi. This review could be useful in the development of practical recommendations for the use of AMF-based fertilizers.

Parthenium hysterophorus L. is considered an obnoxious weed due to its rapid dispersal, fast multiplications, and agricultural and health hazards. In addition to its physio-molecular and phytotoxic allelochemical usage, this weed most probably uses endophytic flora as an additional line of defense to deal with stressful conditions and tolerate both biotic and abiotic stresses. The aim of this article is to report the diversity of endophytic flora (fungi and bacteria) in P. hysterophorus and their role in the stress mitigation (biotic and abiotic) of other important crops. Various endophytes were reported from P. hysterophorus and their roles in crops evaluated under biotic and abiotic stressed conditions. These endophytes have the potential to alleviate different stresses by improving crops/plants growth, development, biomass, and photosynthetic and other physiological traits. The beneficial role of the endophytes may be attributed to stress-modulating enzymes such as the antioxidants SOD, POD and APX and ACC deaminases. Additionally, the higher production of different classes of bioactive secondary metabolites, i.e., flavonoids, proline, and glutathione may also overcome tissue damage to plants under stressed conditions. Interestingly, a number of medicinally important phytochemicals such as anhydropseudo-phlegmcin-9, 10-quinone-3-amino-8-O methyl ether ‘anhydropseudophlegmacin-9, 10-quinone-3-amino-8-O methyl ether were reported from the endophytic flora of P. hysterophorus. Moreover, various reports revealed that fungal and bacterial endophytes of P. hysterophorus enhance plant growth-promoting attributes and could be added to the consortium of biofertilizers.

Impatiens glandulifera , or Himalayan balsam, is a prolific invader of riverine habitats. Introduced from the Himalayas for ornamental purposes in 1839, this annual species has naturalised across Great Britain (GB) forming dense monocultures with negative affects across whole ecosystems. In 2006 a programme exploring biocontrol as an alternative control method was initiated and to date, two strains of the rust fungus Puccinia komarovii var. glanduliferae have been released. To better understand the observed differences in susceptibility of GB Himalayan balsam stands to the two rust strains, inoculation studies were conducted using urediniospores and basidiospores. Experiments revealed large variation in the susceptibility of stands to urediniospores of the two rust strains, with some resistant to both. Furthermore, the infectivity of basidiospores was found to differ, with some stands fully susceptible to the urediniospore stage, being immune to basidiospore infection. Therefore, before further rust releases at new sites, it is necessary to ensure complete compatibility of the invasive stands with both urediniospores and basidiospores. However, for successful control across GB it is essential that plant biotypes are matched to the most virulent rust strains. This will involve additional strains from the native range to tackle those biotypes resistant to the strains currently released. • Multiple biotypes of Himalayan balsam exist in the UK. • Populations differ in their susceptibility to the rust biocontrol agent. • Susceptibility of a population to the mono- and dikaryotic spore stages can differ. • Susceptibility testing using both spore stages required prior to release at a site. • Additional rust strains required for the control of Himalayan balsam in the UK. [ABSTRACT FROM AUTHOR]

The huge demand for natural fibers necessitates the search for non-traditional bioresources including invasive species which are deteriorating the ecosystem and biodiversity. The study aims to utilize Pueraria montana weed for the extraction of lignocellulosic fiber using both traditional (water retting) and chemical extraction methods to determine the better extraction method. Chemically extracted fiber showed 17.09 g/tex bundle strength whereas water-extracted fiber showed 11.7 g/tex bundle strength. Therefore, chemical extraction method was chosen for fiber isolation by optimization of reaction conditions using Box Behnken Design. Based on the design, optimal conditions obtained were 1 % w / v NaOH, 0.75 % v /v H 2 O 2 , and 3 days retting time. Solid-state NMR illustrated the breakdown of hemicellulose linkages at 25.89 ppm. FTIR revealed the disappearance of C=O groups of hemicellulose at 1742 cm−1. TGA demonstrated thermal stability of chemically treated fiber up to 220 °C and activation energy of 60.122 KJ/mol. XRD evidenced that chemically extracted fiber has a crystallinity index of 71.1 % and a crystal size of 2 nm. Thus P. montana weed holds potential for the isolation of natural fiber as its chemical composition and properties are comparable to commercial lignocellulosic fibers. The study exemplifies the transformation of weed to a bioresource of natural fibers. • Energy-efficient and green approach has been developed for extraction of natural fiber from invasive weed Pueraria montana. • Box-Behnken design was used for the optimization of extraction conditions. • Structural, thermal and morphological data was thoroughly studied using Solid State NMR, FTIR, XRD, TGA and SEM analysis. • The cellulose, hemicellulose and lignin composition was comparable to conventionally used lignocellulosic fibers. • The study exemplifies the conversion of a weed into a useful resource. [ABSTRACT FROM AUTHOR]

• Mismatches between resident microbial communities and introduced weed biocontrol pathogens may lead to agent establishment failure. • Plant pathobiomes play an important role in the survival and success of plant pathogens. • Adapting approaches used in animal and crop pathology will improve our understanding of weed pathobiomes. • Weed biocontrol research should begin to incorporate standardized microbial community data collection during new pathogen releases. The role of microbial communities in the establishment of plant pathogens introduced to new environments as weed biocontrol agents is relatively unexplored. Substantial evidence from crop protection research shows how bulk microbial communities influence the establishment, survival, and success of pathogens. Just as mismatches between biocontrol agents, host genotypes, and climate can lead to establishment failure, we propose that mismatches between microbial biocontrol agents and resident microbiomes may be a cause of apparent weed biocontrol failures. From this perspective, we discuss recent progress in research on plant-associated microbial communities whose interactions influence disease development, or "pathobiomes," and consider the implications for biocontrol agent evaluation and release. Open questions about how weed pathobiomes develop and influence agent success rates provide ample opportunity for researchers to adapt new methods and analytical frameworks that will enhance biocontrol programs. We conclude by prioritizing the development of standard methods to include microbiomes as a component of release studies. Developing a pathobiome-aware agent selection and release process will improve agent establishment rates and biocontrol outcomes. [ABSTRACT FROM AUTHOR]

Abutilon theophrasti Medik, Ambrosia artemisiifolia L., Datura stramonium L. and Xanthium strumarium L. are four well-known invasive weed species that are widespread in many crops. Laboratory experiments were conducted to evaluate the allelopathic effects of decomposition products of these four invasive weeds on seed germination and early seedling growth of tomato. The results of the study showed that decomposition products obtained from A. theophrasti, A. artemisiifolia, D. stramonium and X. strumarium had different allelopathic impacts on germination and seedling growth of tomato. The degree of inhibition or stimulation depended on weed species and type of decomposition product. Root decomposition products of all species except X. strumarium decreased the early growth of tomato (2-37%). X. strumarium had only stimulating effect on early growth of tomato (1-86%). Also, the results showed that leaves of the other three invasive weed species had stimulating effects on early growth of tomato (1-53%). Hence, the allelopathic potential of X. strumarium, as well as the leaf decomposition products of the other three invasive weed species could be used to develop an appropriate technology to improve tomato production.

Populations of invasive alien plants create disruptive plant communities that are extremely adaptable, imposing severe ecological impacts on agriculture, biodiversity and human activities. To minimise these impacts, prevention and effective weed management strategies are urgently required, including the identification of satellite populations before they invade new areas. This is a critical element that allows weed management practices to become both successful and cost-effective. Mimosa pigra L. (Giant sensitive plant) is an invasive weed that has spread across various environments around the world and is considered one of the world’s top 100 most invasive plant species. Being adaptable to a wide range of soil types, in addition to its woody protective prickles and low palatability, M. pigra has quickly spread and established itself in a range of habitats. Current control methods of this species include biological, chemical and physical methods, together with attempts of integrated application. Reports suggest that integrated management appears to be the most effective means of controlling M. pigra since the use of any single method has not yet proved suitable. In this regard, this review synthesises and explores the available global literature and current research gaps relating to the biology, distribution, impacts and management of M. pigra. The contribution of this work will help guide land managers to design appropriate and sustainable management programs to control M. pigra.

Invasive plants cause a global loss of biodiversity, pose a major threat to the environment and economy, and also significantly affect agricultural production and food security. Plant growth regulators (PGRs) are widely used in agricultural production and might also affect invasive weeds distributed around crops in various ways. At present, there are few studies concerning whether there are significant effects of PGRs on invasive weeds. In this study, two widely used PGRs in paddy fields, gibberellic acid (GA) and paclobutrazol (PAC), were applied on Oryza sativa and a noxious weed Alternanthera philoxeroides, which is frequently distributed in paddy fields. The purpose of this study was to investigate if there are different responses of rice and weeds to these two plant regulators and the significant effects of PGRs on invasive weeds. The results showed that GA significantly promotes the total biomass of A. philoxeroides by 52.00%, but does not significantly affect that of O. sativa. GA significantly increases the growth of aboveground and belowground A. philoxeroides, but not that of O. sativa. On the other hand, PAC extremely inhibited the aboveground and belowground biomass of A. philoxeroides by more than 90%, but did not significantly inhibit the belowground biomass of O. sativa. PAC also enhanced the leaf nitrogen content and chlorophyll content of A. philoxeroides, but not the traits of O. sativa. Therefore, the effects of PGRs are significantly different between rice and the invasive weed. The potential promotion effects of PGRs on weeds that are frequently distributed in farmland warrant sufficient attention. This is probably one of the important reasons why invasive weeds can successfully invade the agricultural ecosystem with large human disturbance. This study might sound an alarm for weed control in paddy fields.

This paper estimates the return on investment in the skeleton weed management program in Western Australia. A bioeconomic model is used to estimate costs to broadacre cropping industries over time with and without the program. Results suggest that without the program annual crop yield losses and increased growing costs, expressed in Australian dollars ($A), could reach A$13.6 million after 30 years. With the program, these losses reduce to A$5.0 million. If annual skeleton weed program costs remain approximately A$3.4 million, the program is likely to produce an annual net benefit to grain producers of A$8.6 million after 30 years. [ABSTRACT FROM AUTHOR]

Soil salinity represents one of the most restrictive environmental factors for agriculture worldwide. In the present study, the salt tolerance of two weeds of the genus Amaranthus, A. albus and A. hybridus, the latter cultivated as green vegetable in Africa, were analysed. Both species showed a remarkable salt tolerance phenotype during germination and vegetative growth. To evaluate the percentage and rate of germination, seeds were germinated in Petri dishes in a germination chamber under increasing concentrations up to 300 mM NaCl. Higher concentrations of salt ranging from 150 to 600 mM NaCl were applied for one month to plants grown in individual pots in the greenhouse. All seeds of A. albus germinated in the control and almost half of the seeds under 200 mM NaCl, but only 4% of the seeds under 250 mM NaCl. In A. hybridus, germination was considerably lower in all treatments and was completely prevented at 250 mM NaCl. The plant growth of both species was severely affected by high salt concentrations of 450 and 600 mM NaCl, but not under lower concentrations. At this stage of the biological cycle, A. hybridus showed a higher salt tolerance, as indicated by the smaller reduction in its growth parameters. The dry weight of leaves and roots of plants receiving 600 mM NaCl decreased in comparison to control: less than 60% in A. hybridus but more than 70% in A. albus. The salt tolerance of the two species contributes to their invasive potential, but on the other hand represents a useful trait when considering them as potential crops for the future.

We explore the dynamics of invasive weeds by partial differential equation (PDE) modelling and applying dynamical system and phase portrait techniques. We begin by applying the method of characteristics to a preexisting PDE model of the spreading of T. fluminensis, an invasive weed which has been responsible for native forest depletion. We explore the system both at particular points in space and over all of space, in one dimension, as a function of time. Our model suggests that an increase in the rate of spread of the weed through space will increase the efficacy of control measures taken at the weed’s spatial boundary. We then propose new competition models based on the previous model and explore the existence of travelling wave solutions. These models represent both the cases with (i) a competing native plant species which spreads through the forest and (ii) a non-mobile, established native plant species. In the former case, the model suggests that an increased mass-action coefficient between the competing species is sufficient and necessary for the transition of the forest into a state of coexistence. In the latter case, the result is not as strong: a sufficiently large rate of competition between the species excludes the possibility of native plant extinction and hence suggests that forest depletion will not occur, but does not imply coexistence. We perform some numerical simulations to support our analytic results. In all cases, we give a discussion on the physical and biological interpretations of our results. We conclude with some suggestions for future work and with a discussion of the advantages and disadvantages of the methods. [ABSTRACT FROM AUTHOR]

The efficacy of Segador (organic fertilizer with a contact herbicide effect), applied alone or in combination with the adjuvant Melamyel for controlling of the invasive weed species Sorghum halepense (L.) Pers., Cirsium arvense (L.) Scop. and Convolvulus arvensis L. in non-cropped areas was studied. Segador at concentration 5%, 8% and 12% indicated high efficiency from 95 to 100%. It proved to be a successful element in a strategy for controlling of invasive weed species (Cirsium arvense (L.) Scop. and Convolvulus arvensis L.) and greatly important for reducing to population density of perennial dicotyledonous weeds. The resistance of Segador was demonstrated to Sorghum halepense (L.) Pers. at all tested rates with or without Melamyel. Segador successfully controlled perennial dicotyledonous weeds, but it was not toxic to Sorghum halepense (L.) Pers. [ABSTRACT FROM AUTHOR]

Nonnative plant infestations provide unique opportunities to investigate pathogen emergence with evolutionarily recent plant introduction events. The widespread distribution of invasive plants and their proximity to genetically related crops highlights the risks of nonnative plants acting as ancillary hosts and fostering microbial recombination and pathogen selection. Garlic mustard ( Alliaria petiolata ) is a widespread, nonnative cruciferous weed that grows throughout North America and along the forested edges of diverse agricultural fields. The recent identification of a novel Xanthomonas campestris pv. incanae strain isolated from a diseased A. petiolata population led to the current investigation of the distribution and diversity of X. campestris isolates from naturally infected A. petiolata . A total of 14 diseased A. petiolata sites were sampled across three states, leading to the identification of diverse X. campestris pathotypes and genotypes. Pathogenicity assays and multilocus sequence analyses identified pathogenic X. c. pv. incanae and X. c. pv. barbareae strains collected from disparate A. petiolata populations. Moreover, independently collected X. c. pv. incanae strains demonstrated a broad cruciferous host range by infecting cabbage ( Brassica oleracea var. capitata ), garden stock ( Matthiola incana ), and the cover crop yellow mustard ( Guillenia flavescens ). This study highlights the genetic variability and host potential of natural X. campestris populations and the potential risks to Brassica crops via widespread, dense garlic mustard reservoirs., Competing Interests: The author(s) declare no conflict of interest.

Three main Ambrosia species (Ragweed) grow in Israel; the most abundant invasive Ambrosia confertiflora DC, whereas A. artemisiifolia L. and A. tenuifolia Spreng., are of restricted distribution. The present research was aimed to study the effect of temperatures regimes on the development and growth of these Ambrosia species, to elucidate the environmental conditions and plant traits that affect their growth and infestation patterns. All three Ambrosia species germinate best in light from the soil surface with no prerequisite of a stratification period. A. confertiflora seed emergence is inhibited at high temperature regimes (28/34°C). A. artemisiifolia at low temperature regimes (10/16°C), while A. tenuifolia is less affected by the temperature regimes. A. confertiflora plant height increases with increasing temperatures, and at lower temperatures develops a rosette. Root and rhizome biomass were less affected by the different temperatures regimes; A. artemisiifolia aboveground mass was not affected by temperature regimes while A. tenuifolia aboveground mass was reduced only at lower temperatures. A. confertiflora fast invasion and establishment are due to the combined effects of prolific seed dispersal, rapid sprouting and growth, and its phenotypic plasticity.

In the present study, we conducted field surveys to detect the population density of the most important invasive weed species and their associated virus vectoring aphids in crops grown under high input field (HIF) vs. low-input field (LIF) conditions, with and without fertilizers and pesticides. The most frequent invasive weed species were annual fleabane, Erigeron annua (L.), Canadian horseweed, Erigeron canadensis (L.) and Canadian goldenrod, Solidago canadensis (L.). These species were predominantly hosts of the aphids Brachycaudus helichrysi and Aulacorthum solani under both management systems. The 13% higher coverage of E. annua under LIF conditions resulted in a 30% higher B. helichrysi abundance and ∼85% higher A. solani abundance compared with HIF conditions. To reveal the incidence of virus infection in crop plants and invasive weeds, high-throughput sequencing of small RNAs was performed. Bioinformatics analysis combined with independent validation methods revealed the presence of six viruses, but with strikingly different patterns under LIF and HIF conditions. Their presence without symptoms in invasive weeds and crop plants supports the necessity of employing new approaches to those currently employed in invasive weed management. These findings also suggest that invasive weeds could serve as hosts for local aphid species and reservoirs for plant pathogenic viruses, both under low and high input management systems. In this light, as here demonstrated, viruses transmitted by local aphid species were found to differ between the management systems; hence, the importance of B. helichrysi and A. solani as virus vectors in particular clearly needs to be re-evaluated. Altogether, we accept that the present study is a pilot one and individual virus vectoring of aphids still needs to be directly tested. Even so, it represents one of the first contributions to this particular area, and thereby paves the way for further similar applied research in the future.

With increasing globalization, trade, and human movement, the rate of alien species introduction has increased all around the globe. In addition, climate change is thought to exacerbate the situation by allowing range expansion of invasive species into new areas. Predicting the distribution of invasive species under conditions of climate change is important for identifying susceptible areas of invasion and developing strategies for limiting their expansion. We used Maxent modeling to predict the distribution of one of the world's most aggressive invasive weeds, Ageratina adenophora (Sprengel) R. King and H. Robinson, in the Chitwan–Annapurna Landscape (CHAL) of Nepal under current conditions and 3 future climate change trajectories based on 3 representative concentration pathways (RCPs 2.6, 4.5, and 8.5) in 2 different time periods (2050 and 2070) using species occurrence data, and bioclimatic and topographic variables. Minimum temperature in the coldest month was the most important variable affecting the distribution of A. adenophora. About 38% (12,215 km2) of the CHAL area is climatically suitable for A. adenophora, with the Middle Mountain physiographic region being the most suitable one. A predicted increase in current suitable areas ranges from 1 to 2% under future climate scenarios (RCP 2.6 and RCP 8.5). All protected areas and 3 physiographic regions (Siwaliks, High Mountain, High Himalaya) are likely to gain climatically suitable areas in future climate scenarios. The upper elevational distribution limit of the weed is expected to expand by 31–48 m in future climate scenarios, suggesting that the weed will colonize additional areas at higher elevations in the future. In conclusion, our results showed that a vast area of CHAL is climatically suitable for A. adenophora. Expected further range expansion and upslope migration in the future make it essential to initiate effective management measures to prevent further negative impacts of this invasive plant.

Study on production of briquettes from two invasive forest weeds, i.e., Lantana camara and Prosopis juliflora was carried out. The experiments were carried out using a 90 mm industrial briquetting unit. The optimum moisture content for briquetting was found around 10–12%. L. camara and P. juliflora biomass briquettes were found to have high density (1.2 g cm−3) and high energy density (23.05 GJ m−3). In this study, fuel properties (calorific value, proximate and ultimate analysis), combustion characteristics and ash elemental composition of L. camara and P. juliflora biomass were investigated. Both the species are found to have less ash content. Further, high CaO content in ash (47–68%) gives added advantage to these species. In this study, we have also worked out the cost involved in briquetting. The emphasis was given to these species because of the huge biomass they produce. These species are widely present in different agro-climatic zones of India and can play a major role in future bioenergy schemes. [ABSTRACT FROM AUTHOR]

Agroecosystems play a critical role in rural economics and contribute to the national economy. However, these areas are currently threatened by invasive species. Timely information on potential hotspots and affected areas is required for management purposes. We assess the spatial distribution patterns of Lantana camara invasion in savanna rangeland ecosystems before and after clearing (2014, 2016 and 2018), using high-resolution SPOT 6 data, in Agincourt, South Africa. A maximum likelihood classification algorithm was applied to SPOT 6 data to detect and map areas affected by this invasive species. Furthermore, different accuracy assessment measures (e.g. producer accuracy (PA), user accuracy (UA) and overall accuracy (OA)) were used to assess the validity of the classification results, namely built-up areas, bare areas, uninvaded areas and invaded areas. The results demonstrate that Lantana camara occurrence in rangelands ecosystems can be mapped with high accuracy. An overall accuracy of 81.29% was attained for 2014, 86.85% for 2016 and 88.69% for 2018. It was further observed that in 2016 Lantana camara occurrence was minimal when compared to 2014, but the results indicate regeneration in 2018 in previously cleared areas. Approximately 40.84% of the area was covered by Lantana camara in 2014, 25.19% in 2016 and 27.02% in 2018. Overall, the findings in this study underscore the need for continuous monitoring of affected areas, especially after clearing, to continuously advise on areas that are at risk for potential re-establishment of invasive weeds. [ABSTRACT FROM AUTHOR]

In the present study, we conducted field surveys to detect the population density of the most important invasive weed species and their associated virus vectoring aphids in crops grown under high input field (HIF) vs. low-input field (LIF) conditions, with and without fertilizers and pesticides. The most frequent invasive weed species were annual fleabane, Erigeron annua (L.), Canadian horseweed, Erigeron canadensis (L.) and Canadian goldenrod, Solidago canadensis (L.). These species were predominantly hosts of the aphids Brachycaudus helichrysi and Aulacorthum solani under both management systems. The 13% higher coverage of E. annua under LIF conditions resulted in a 30% higher B. helichrysi abundance and ∼85% higher A. solani abundance compared with HIF conditions. To reveal the incidence of virus infection in crop plants and invasive weeds, high-throughput sequencing of small RNAs was performed. Bioinformatics analysis combined with independent validation methods revealed the presence of six viruses, but with strikingly different patterns under LIF and HIF conditions. Their presence without symptoms in invasive weeds and crop plants supports the necessity of employing new approaches to those currently employed in invasive weed management. These findings also suggest that invasive weeds could serve as hosts for local aphid species and reservoirs for plant pathogenic viruses, both under low and high input management systems. In this light, as here demonstrated, viruses transmitted by local aphid species were found to differ between the management systems; hence, the importance of B. helichrysi and A. solani as virus vectors in particular clearly needs to be re-evaluated. Altogether, we accept that the present study is a pilot one and individual virus vectoring of aphids still needs to be directly tested. Even so, it represents one of the first contributions to this particular area, and thereby paves the way for further similar applied research in the future. [ABSTRACT FROM AUTHOR]

With increasing globalization, trade, and human movement, the rate of alien species introduction has increased all around the globe. In addition, climate change is thought to exacerbate the situation by allowing range expansion of invasive species into new areas. Predicting the distribution of invasive species under conditions of climate change is important for identifying susceptible areas of invasion and developing strategies for limiting their expansion. We used Maxent modeling to predict the distribution of one of the world's most aggressive invasive weeds, Ageratina adenophora (Sprengel) R. King and H. Robinson, in the Chitwan–Annapurna Landscape (CHAL) of Nepal under current conditions and 3 future climate change trajectories based on 3 representative concentration pathways (RCPs 2.6, 4.5, and 8.5) in 2 different time periods (2050 and 2070) using species occurrence data, and bioclimatic and topographic variables. Minimum temperature in the coldest month was the most important variable affecting the distribution of A. adenophora. About 38% (12,215 km2) of the CHAL area is climatically suitable for A. adenophora, with the Middle Mountain physiographic region being the most suitable one. A predicted increase in current suitable areas ranges from 1 to 2% under future climate scenarios (RCP 2.6 and RCP 8.5). All protected areas and 3 physiographic regions (Siwaliks, High Mountain, High Himalaya) are likely to gain climatically suitable areas in future climate scenarios. The upper elevational distribution limit of the weed is expected to expand by 31–48 m in future climate scenarios, suggesting that the weed will colonize additional areas at higher elevations in the future. In conclusion, our results showed that a vast area of CHAL is climatically suitable for A. adenophora. Expected further range expansion and upslope migration in the future make it essential to initiate effective management measures to prevent further negative impacts of this invasive plant. [ABSTRACT FROM AUTHOR]

The life history and host range of the South American defoliator Paectes n. sp. (Lepidoptera: Euteliidae) was evaluated to determine its suitability for classical biological control of invasive Brazilian peppertree, Schinus terebinthifolia, in the U.S.A. The genus Paectes is well represented in both Florida and South America. We used DNA barcoding to assign our Paectes collections to species. However, this method did not match any known species of this genus. Larvae were collected feeding on the target weed in Brazil in June 2015 and were colonised under quarantine with mating pairs. Larval no-choice host range tests were conducted on nine members of the family Anacardiaceae, including native, ornamental, and commercial species. Larvae completed development on all species except Anacardium occidentale and Mangifera indica, although survival and development time differed significantly among species. Multiple generation testing was conducted using survivors of no-choice tests. Non-target species Schinus molle, Rhus typhina, and Cotinus coggygria produced F1 adults, although only the target weed produced F2 adults. The results of the testing suggest that although Paectes n. sp. is only capable of completing multiple generations on the target weed, Paectes larvae consume and complete at least one generation on a number of native and commercial Anacardiaceae species. Due to its relatively broad host range, and because congener species feed on the weed in the invaded range, Paectes n. sp. will not be developed as a classical biological control of Brazilian peppertree in the U.S.A. [ABSTRACT FROM AUTHOR]

Predicting the distribution of invasive weeds under climate change is important for the early identification of areas that are susceptible to invasion and for the adoption of the best preventive measures. Here, we predicted the habitat suitability of 16 invasive weeds in response to climate change and land cover changes in South Korea using a maximum entropy modeling approach. Based on the predictions of the model, climate change is likely to increase habitat suitability. Currently, the area of moderately suitable and highly suitable habitats is estimated to be 8877.46 km2, and 990.29 km2, respectively, and these areas are expected to increase up to 496.52% by 2050 and 1439.65% by 2070 under the representative concentration pathways 4.5 scenario across the country. Although habitat suitability was estimated to be highest in the southern regions (

The life history and host range of the South American leaf-tier Tentamen atrivirgulatum Metz, 2019 (Lepidoptera: Gelechiidae) was evaluated to determine its suitability for classical biological control of invasive Brazilian peppertree, Schinus terebinthifolia, in the USA. Larvae were collected during a survey in the native range of Brazil feeding on Brazilian peppertree. A quarantine colony was established and no-choice tests were conducted to determine the host range of this species. The results of these tests indicated that the larvae fed and completed development on seven of the eleven non-target species tested. Percent survival on these non-targets ranged from 20% to 100%. Larval survival was 50% when fed the target weed Brazilian peppertree. When larvae were fed leaves of these non-targets, pupal weights were significantly lower only for those fed Pistacia chinensis. Development time to the pupal and adult stages did not differ with larval diet. These no-choice results indicate T. atrivirgulatum larvae have a broad host range and thus this species will not be developed as a biological control agent for Brazilian peppertree in the USA. [ABSTRACT FROM AUTHOR]

Summary: Despite their putative invasive potential, Miscanthus taxa have been increasingly viewed as promising crops for bioenergy production. Miscanthus x giganteus is cultivated worldwide due to its high productivity, and its non‐spreading growth limits its risk of invasion. However, the genetic uniformity of its unique cultivated clone has recently been questioned. We used morphometry, nuclear microsatellites, AFLP fingerprints and nrDNA ITS barcoding to assess Miscanthus genotypes cultivated in eastern France. As expected, the globally cultivated clone was the main morphotype and genotype of our samplings; however, we also identified a second genotype, assigned to M. sacchariflorus, in the sampled fields. Morphological differentiation partially overlaps genotypic assignation, probably due to disturbance at the crop edges. We also show that Miscanthus taxa are misidentified in commercial nurseries. Our study confirms previous reports of the occurrence of other accessions in fields of M. x giganteus. These taxonomic confusions limit the certainty that a single clone of M. x giganteus is cultivated. In this context, M. x giganteus crop fields may actually promote the dispersal of invasive Miscanthus taxa. [ABSTRACT FROM AUTHOR]

Phytotoxicity of two invasive weed species Parthenium hysterophorus L. and Xanthium strumarium L. collected from three different sites viz., Charsadda, Mardan and Peshawar districts of Khyber Pakhtunkhwa were tested against five chickpea varieties in completely randomized design having three replications. The weed species extract revealed highly significant inhibitory effect on chickpea varieties. Among the applied extracts; extract prepared from Parthenium weed collected from Charsadda proved to be more toxic as compared to extracts prepared from other areas, by inhibiting the germination of chickpea to the extent of 91.4%. Maximum and minimum average root weight of 0.56 g and 0.15g among different chickpea varieties was recorded for Peshawar Xanthium and Charsadda Parthenium, respectively. Maximum mean shoot length of 0.29 cm was evident for the control treatment (no extract) whereas minimum mean shoot length of 0.09 cm was observed for chickpea varieties treated involving Charsadda Xanthium. Maximum and minimum mean shoot weight of 2.40 g and 0.77 g were manifested by different chickpea varieties treated by Control (no treatment) and Charsadda Parthenium, respectively. Similarly maximum mean seed vigour index (SVI) of (225.13) was evident for control treatment whereas Extracts from Charsadda Parthenium manifested minimum mean seed vigour index (69.63) in different chickpea varieties under test. It is evident from the results of varietal response of chickpea to common cocklebur (Xanthium strumarium) and parthenium (Parthenium hysterphorus) treatment that chickpea varieties showed tolerance against the phytotoxcity of these invasive weeds. Therefore, it could be used as bio herbicide if it is effective in controlling weeds of chickpea. [ABSTRACT FROM AUTHOR]

In isolated islands with low pollinator diversity, it has been suggested that native pollinators should evolve into super-generalists that could facilitate the spread of exotic plant species that might otherwise rely on specialist pollinators. Consequently, in the absence of exotic pollinators isolated islands may still be particularly vulnerable to a wide variety of introduced plants. Fiji has a highly abundant and diverse introduced plant fauna, as well as a variety of introduced bee species, but has extremely low endemic bee fauna diversity. We examined bee–plant pollination networks in lowland regions of Viti Levu (Fiji) where there is only one endemic bee species, Homalictus fijiensis. We show that this bee is a super-generalist for introduced plants, and whilst introduced bee species can show high intensities of floral visits, they do not substantially increase the breadth of weeds receiving bee visits. Surprisingly, one introduced plant species, Sphagneticola trilobata, receives high visitations from introduced bee species, even though it spreads vegetatively. We regard this species as a 'Parlourmaid' weed that likely augments the spread of exotic bees without gaining pollination benefits. Our results indicate a 'twofold' promotion of invasive species, namely, super-generalist native pollinators can promote the spread of diverse introduced plants, and Parlourmaid plants provide resources that can promote the spread of introduced pollinators. [ABSTRACT FROM AUTHOR]

Extracts of many plant species have substantial antifungal activity, therefore the use of plant extracts with good activity against plant fungal pathogens could lead to the development of inexpensive and environmentally acceptable fungicides based on locally available natural products. Because large quantities of invasive weeds are available we decided to determine the antifungal activity of acetone extracts of seven invasive weeds (Aristolochia elegans, Chromolaena odorata, Ipomoea alba, Passiflora suberosa, Passiflora subpeltata, Solanum seaforthianum and Tecoma stans). The activity was determined against eight plant fungal pathogens viz Rhizoctonia solani, Fusarium oxysporium, Penicillium janthinellum, Penicillium expansum, Aspergillus parasiticus, Aspergillus niger, Pythium ultimum and Phytophthora nicotiana. Extracts of some invasive plant species had better activity against some fungal pathogens than some commercial fungicides. P. suberosa had promising antifungal activity with an average minimum inhibitory concentration (MIC) of 0.09 mg/ml. Tecoma stans extracts were not as active (average MIC 0.55 mg/ml). This extract, however contained compounds that yielded clear inhibition zones in bioautography making it easy to isolate the active compound by bioassay guided fractionation. • There is an abundance of invasive plant material available. • Invasive plants may have good antifungal activity as a competitive advantage. • Determined activity of seven invasive plant species against eight fungal pathogens. • The number of active compounds were determined by bioautography. • Some extracts sufficiently active to protect plant crops against fungal pathogens. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Bioethanol fermentation (SHF protocol) using mixed feedstock of 8 invasive weeds. • Fitting of fermentation profiles to biokinetic model using Genetic Algorithm. • Total ethanol yield from pentose and hexose fermentation = 220 g/kg raw biomass. • Faster transport of nutrients, substrate and products across cell membrane with sonication. • Rise in Monod saturation constant for substrate with reduction in substrate inhibition. Abstract Invasive weeds ubiquitously found in terrestrial and aquatic ecosystems form potential feedstock for lignocellulosic ethanol production. The present study has reported a bioprocess for production of ethanol using mixed feedstock of 8 invasive weeds found in India. The feedstock was subjected to pretreatment comprising dilute acid hydrolysis (for hydrolysis of hemicellulosic fraction), alkaline delignification and enzymatic hydrolysis of cellulosic fraction. Pentose-rich and hexose-rich hydrolyzates obtained from pretreatment were fermented separately using microbial cultures of S. cerevisiae and C. shehatae. Fermentation mixture was sonicated at 35 kHz at 10% duty cycle. The time profiles of total reducing sugars, ethanol and biomass was fitted to a kinetic model using Genetic Algorithm. Sonication boosted the kinetics of fermentation 2-fold. The net bioethanol yield of the process was ∼220 g/kg raw biomass (with contributions of 86.8 and 133 g/kg raw biomass from pentose and hexose fermentations, respectively). Comparative evaluation of parameters of kinetic model under control and test conditions revealed several beneficial influences of sonication on both pentose and hexose fermentation systems such as faster transport of nutrients, substrate and products across cell membrane, rise in Monod saturation constant for substrate with concurrent reduction in substrate inhibition, and reduction of energy requirements for cell maintenance. Flow cytometry analysis of native and ultrasound-treated cells revealed no adverse influence of sonication on cell viability. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Ultrasonic ABE fermentation using C. acetobutylicum and mixed invasive weeds. • Net ABE solvent yield with sonication = 0.288 g/g raw biomass in 92 h fermentation. • Analysis of substrate and metabolites profiles using biokinetic model. • Sonication boosts kinetics of metabolism with reduced saturation constants. • Flow cytometry analysis revealed high cell viability during exposure to sonication. Abstract This study reports an ultrasound-assisted Acetone-Butanol-Ethanol (ABE) fermentation process using Clostridium acetobutylicum MTCC 11,274 and mixed feedstock consisting of eight highly invasive weeds. Composite (pentose + hexose) hydrolyzate was fermented with sonication at 35 kHz and 10% duty cycle (test) and mechanical agitation at 150 rpm (control). Net solvent yield with sonication was 0.288 g/g raw biomass in 92 h against yield of 0.168 g/g raw biomass in 120 h with mechanical agitation. Butanol yield in test and control fermentation was 0.233 and 0.149 g/g total fermentable sugar, respectively. Substrate and metabolites profiles in test and control fermentation were analyzed using biokinetic model. Sonication enhanced kinetics of metabolic reactions with rise in substrate affinity of enzymes (reduced saturation constants) and greater resistance to substrate inhibition. Flow cytometry analysis of cells exposed to sonication revealed high cell viability with no adverse effect on physiology. [ABSTRACT FROM AUTHOR]

Diverse freshwater biological communities are threatened by invasive aquatic alien plant (IAAP) invasions and consequently, cost countries millions to manage. The effective management of these IAAP invasions necessitates their frequent and reliable monitoring across a broad extent and over a long-term. Here, we introduce and apply a monitoring approach that meet these criteria and is based on a three-stage hierarchical classification to firstly detect water, then aquatic vegetation and finally water hyacinth (Pontederia crassipes, previously Eichhornia crassipes), the most damaging IAAP species within many regions of the world. Our approach circumvents many challenges that restricted previous satellite-based water hyacinth monitoring attempts to smaller study areas. The method is executable on Google Earth Engine (GEE) extemporaneously and utilizes free, medium resolution (10–30 m) multispectral Earth Observation (EO) data from either Landsat-8 or Sentinel-2. The automated workflow employs a novel simple thresholding approach to obtain reliable boundaries for open-water, which are then used to limit the area for aquatic vegetation detection. Subsequently, a random forest modelling approach is used to discriminate water hyacinth from other detected aquatic vegetation using the eight most important variables. This study represents the first national scale EO-derived water hyacinth distribution map. Based on our model, it is estimated that this pervasive IAAP covered 417.74 km2 across South Africa in 2013. Additionally, we show encouraging results for utilizing the automatically derived aquatic vegetation masks to fit and evaluate a convolutional neural network-based semantic segmentation model, removing the need for detection of surface water extents that may not always be available at the required spatio-temporal resolution or accuracy. The water hyacinth species discrimination has a 0.80, or greater, overall accuracy (0.93), F1-score (0.87) and Matthews correlation coefficient (0.80) based on 98 widely distributed field sites across South Africa. The results suggest that the introduced workflow is suitable for monitoring changes in the extent of open water, aquatic vegetation, and water hyacinth for individual waterbodies or across national extents. The GEE code can be accessed here.

Old, abandoned feedlots may serve as a source of nutrients that can degrade groundwater and downstream water quality. We characterized the distribution and concentration of nutrients at the Crookston Cattle Company feedlot (northwest Minnesota, USA), 15 years after it ended operations in 1999. Groundwater nitrate concentration decreased from 55 mg/L (as nitrogen) in 2003 to less than 5 mg/L since 2007. Results from stable isotope analysis, with δ15N and δ18O in groundwater nitrate ranging up to +44 and +30‰, respectively, suggest denitrification as the cause, rather than either nitrate transport from the site or dilution. Phosphorus, with soil B-horizon concentrations as much as 112 and averaging 24 mg/kg, is sequestered by carbonate-rich glacial sediments and, serendipitously, an iron-rich sand deposit formed millennia ago by wave action along the shore of glacial Lake Agassiz. Map analysis indicates roughly 20,000 kg of P in excess of background concentration remains in soil at the 15 ha site. Evidence suggests that the former feedlot has not affected water quality significantly in an agricultural ditch that drains the feedlot and its vicinity. Rather than originating from the feedlot, small increases of total phosphorus observed in the downstream ditch likely result from release of phosphorus from nearby recently restored wetlands. More consequential than elevated nutrient concentrations to the future reclamation of this and similar sites is the persistence of robust non-native species. Our results suggest that before development, feedlot sites should be evaluated for their phosphorus sequestration and denitrification potential, thus mitigating the potential for later off-site transport of nutrients.

Life cannot exist without water. Appropriate management of water, from the water’s source to its utilization, is necessary to sustain life. Aquatic weeds pose a serious threat to aquatic environments and related eco-environments. Short- and long-term planning to control aquatic weeds is extremely important. Water hyacinth, Eichhornia crassipes (Mart.) Solms, is one of the world’s worst pests with a bad reputation as an invasive weed. In this study we are seeking the possibility of using certain chemicals with a natural background, for controlling water hyacinth since there is a delicate balance that needs to be taken into account when using herbicides in water. Five compounds, namely: acetic acid, citric acid, formic acid, and propionic acid, in three concentrations (10, 15, and 20%) were applied (i.e. as a foliar application under wire-house conditions) and compared with the use of the herbicide glyphosate (1.8 kg ∙ ha−1). All of the five compounds performed well in the control of the water hyacinth. As expected, the efficacy increased as the concentration was increased from 10 to 20%. With formic and propionic acids, the plants died earlier than when the other acids or the herbicide glyphosate, were used. Acetic acid came after formic and propionic acids in terms of efficacy. Citric acid ranked last. Formic acid/propionic acid mixtures showed superior activity in suppressing water hyacinth growth especially at the rate of (8 : 2) at the different examined concentrations (3 or 5 or 10%) compared to the formic acid/acetic acid mixtures. Using the formic acid/propionic acid mixture (8 : 2; at 3%) in the open field, provided good control and confirmed the viability of these chemicals in the effective control of water hyacinth. Eventually, these chemical treatments could be used on water for controlling water hyacinth. In the future, these chemicals could probably replace the traditional herbicides widely used in this regard. These chemicals are perceived as environmentally benign for their rapid degradation to carbon dioxide and water. For maximum efficiency thorough coverage especially in bright sunlight is essential.

Classical biological control can provide an ecologically sound, cost‐effective, and sustainable management solution to protect diverse habitats. These natural and managed ecosystems are being invaded and transformed by invasive species. Chinese tallowtree, Triadica sebifera (L.) Small (Euphorbiaceae), is one of the most damaging invasive weeds in the southeastern USA, impacting wetlands, forests, and natural areas. A defoliating moth, Gadirtha fusca Pogue (Lepidoptera: Nolidae), was discovered feeding on Chinese tallowtree leaves in the weed's native range and has been tested for its suitability as a biological control agent. Natural history studies of G. fusca indicated that the neonates have five instars and require 15.4 days to reach pupation. Complete development from egg hatch to adult emergence required 25.8 days. No differences were found between males and females in terms of life history and nutritional indices measured. Testing of the host range of G. fusca larvae was conducted with no‐choice, dual‐choice, and multigeneration tests and the results indicated that this species has a very narrow host range. No‐choice experiments indicated that most larvae died in <3 days when fed each of the 78 non‐target taxa; a similar duration as larvae fed only water. Although 81.6% of the neonates fed Chinese tallowtree survived to adult, the only survivors in no‐choice tests were those fed the four non‐target taxa, Euphorbia hypericifolia L., Euphorbia hyssopifolia L., Euphorbia milii Des Moul., or Gymnanthes lucida Sw. where 14.3% or less of the larvae fed and completed development. The results of dual‐choice tests indicated that very little of each of these non‐target taxa was eaten when given a choice with Chinese tallowtree. Furthermore, when neonates were reared for multiple generations on each non‐target taxon, no more than two generations were completed when fed the non‐target G. lucida, whereas the larvae were unable to complete more than one generation when fed the remaining non‐targets. These tests indicate that although a small amount of feeding may occur in no‐choice conditions on four species of non‐targets, the larvae will not be able to maintain a population for more than two generations on any species except the target weed Chinese tallowtree. This species may play an important role and contribute to the integrated control of this invasive weed. This research examined the quarantine host range of Gadirtha fusca (Lepidoptera: Nolidae), a potential biological control agent of Chinese tallowtree (Euphorbiaceae). Results indicate that this species has narrow specificity and will be a safe control agent of this invasive weed. [ABSTRACT FROM AUTHOR]

Kakadu National Park and its wetlands are World Heritage and Ramsar listed and are at risk from invasive grasses. However, it appears that not all habitats and native vegetation are equally at risk. We conduct a spatial risk assessment for para grass ( Urochloa mutica ) invasion across seasonally inundated habitats of the 258 km 2 Magela Creek floodplain within Kakadu National Park using Landsat 5 TM time-series imagery. Two maps, representing water depth and fire history, were derived from the imagery using object-based image analyses. Depth was modelled using a linear regression relationship established between 254 known water depth locations and the multi-date spectral index values of segmented image objects at corresponding locations (R 2  = 0.67; p < 0.0001). Binary fire-scar maps were then produced for each year of a 10-year period using visual interpretation and nearest neighbour classification. A map of the incidence of annual fire over this period was then calculated from the sum of the maps, overlaid. The maps were integrated in a GIS with an existing Landsat vegetation map to measure spatial inter-relationships between para grass, native vegetation, depth and fire. With a highly clustered distribution pattern, para grass occupied 1388 ha or 6% of the total floodplain area. However, its optimal depth habitat, estimated to be from 1.1 to 1.4 m, occurred over a much larger area (7180 ha) or 30% of the floodplain. Only 2% of this optimal area was actually occupied by para grass. Together the low occupancy of ‘optimal-depth’ habitat and a highly clustered distribution of para grass strongly suggested that, if left uncontrolled, it has capacity to spread further and eventually occupy much larger areas of this floodplain at high density. Landsat provided spatial information of suitable scale and accuracy to understand the landscape ecology of para grass; and from which to design and conduct further research, or trial management interventions to protect wetland vegetation at risk to weed invasion. [ABSTRACT FROM AUTHOR]

Ipomoea carnea Jacq., also called Ipomoea fistulosa, is among the world's 100 most invasive weeds. Its ability to grow explosively on land as well as in wetlands gives it a unique competitive advantage over other major weeds like Lantana, Prosopis and water hyacinth, which are either aquatic or terrestrial. This paper presents an overview of the invasiveness and colonizing ability of Ipomoea in the context of the its attributes that facilitate its spread. The manner in which Ipomoea infestation harms the environmental health is also described. The numerous ways that have been explored to utilize Ipomoea have been enumerated. In the context of the inadequacy of these attempts, an emerging technology, which promises to solve the Ipomoea problem, is described. [ABSTRACT FROM AUTHOR]

Chinese tallowtree, Triadica sebifera (L.) Small (Euphorbiaceae), is one of the worst invasive weeds of the southeastern USA impacting coastal wetlands, forests, and natural areas. A proposed biological control candidate, the defoliating moth Gadirtha fusca Pogue (Lepidoptera: Nolidae) shows high specificity for the target weed Chinese tallowtree. A total of 13 field sites were sampled in the native range of this herbivore species. To determine if all individuals were the same taxon, molecular DNA analyses were conducted of these collections. These included collections from 2012, 2015 and 2016, from three regions and two adult color morphs. Molecular COI analysis was performed on thirty colonized individuals from these collections. The results of this analysis arranged all taxa into a single clade with average genetic divergence values of 0.3%. Comparison of these G. fusca sequences and those from other Gadirtha spp. all had divergence values that were equal to or exceeded 5%. These results indicate that all the G. fusca collections were a single species and they were distinct from other known members of this genus. [ABSTRACT FROM AUTHOR]

Integrating classical biological control with other management techniques such as herbicide, fire, mechanical control, grazing, or plant competition, can be the most effective way to manage invasive weeds in natural areas and rangelands. Biological control agents can be protected from potential negative impacts of these weed control methods through untreated refugia or by applying the treatment at a time when the agent is not vulnerable. A literature review of experiments that integrated biological control with other management strategies from 1987 to 2017 yielded 39 terrestrial and 16 aquatic studies. The tactics most frequently integrated with biological control were herbicide applications and plant competition. Despite numerous examples of successful programs and calls for more widespread integration of biological control with other weed management strategies, there was no increase in the number of studies reported annually over time. Additional studies investigating the ecological and economic benefits of integrated weed management are needed. [ABSTRACT FROM AUTHOR]

Plant populations invading new environments might compromise their fitness contribution to the next generation, because of the lack of native specialist pollinators and/or potential mates. Thus, changes in plant mating system and traits linked to it are expected in populations colonising new environments where selection would favour selfing and floral traits that maximise reproductive output. To test this, we studied native (Mexico) and non-native (Spain) populations of the obligate sexual reproducing annual weed Datura stramonium., Flower size, herkogamy, total number of seeds per plant, number of visits by and type of pollinators, and inbreeding depression were assessed in native and non-native populations. Finally, we measured phenotypic selection on corolla size and herkogamy in each population., Flower size and herkogamy showed wide and similar variation in both ranges. However, the largest average flower size was found in one non-native population whereas the highest average positive herkogamy was detected in one native population. On average, flowers in the native range received more visits by pollinators. Hawkmoths were the main visitors in the native populations while only bees were observed visiting flowers in Spain's populations. Only in the native range was inbreeding depression detected. Selection to reduce herkogamy was found only in one native population., Absence of both inbreeding depression and selection on floral traits suggest a change in mating system of D. stramonium in a new range where generalist pollinators may be promoting high reproductive success. Selection against deleterious alleles might explain the reduction of inbreeding depression, promoting the evolution of selfing. [ABSTRACT FROM AUTHOR]