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Chromolaena odorata (L.) R.M. King and H. Robinson (Asteraceae) is one of the worst invasive weeds in Africa, Asia, and the Pacific. Cecidochares connexa (Macquart) (Diptera: Tephritiidae) is a bio...

The invasive annual grasses barb goatgrass (Aegilops triuncialis L.) and medusahead (Elymus caput-medusae L.) are widespread in western states and present management challenges on grasslands. To develop an integrated management strategy for these species, we treated sites in five pastures in Mendocino County, comparing combinations of intensive sheep grazing, glyphosate herbicide (low and high), and application timings (tillering, boot and heading stage). We found that grazing alone reduced barb goatgrass spikelet densities by 68% and the number of seeds per spikelet by 35%. Both rates of glyphosate application without grazing had similar effects on seed production. High and low glyphosate application at tillering resulted in almost complete control of both target species. Boot- and heading-stage applications reduced barb goatgrass density by 39% and 32%, respectively. Application at the boot stage also resulted in an 82% reduction in number of seeds per barb goatgrass spikelet. Our results suggest that intensive grazing may be a useful management strategy to reduce barb goatgrass and medusahead spikelet densities and barb goatgrass seed numbers, especially when integrated with a boot- or heading-stage glyphosate application.

Germination abilities endorsed the successful invasion and establishment regularly of Silverleaf nightshade (Solanum elaeagnifolium Cav.) to be one of the most serious invasive weeds in the world. Therefore, their seed sets were exposed to different thermogradient temperatures and light/dark regimes with and without chemical and physical treatments to determine the germination requirements and conditions. The percentage of seed germination is generally low and reached the optimum at alternating temperature regimes of 20/30 °C (32.8%), followed by 15/25 ℃ (31.5%) and 20/25 ℃ (30.0%), respectively under 12/12 (day/night) within four weeks. While it failed to germinate at constant temperatures. The superlative treatment was achieved from combined heat at 100oC with gibberellic acid at 1000 ppm reached 65% of seed germination over the control. Time exposure and concentration of various chemical and physical promotors have significant effects on germination and breaking their seed dormancy. S. elaeagnifolium seed germination was diminished progressively to ≤ 3000 ppm of NaCl but their growth has more enough resistance. While the range of 8 to 9 pH is preferential to the maximum germination. We concluded that alternating temperatures are basic requirements of S. elaeagnifolium seed germination while it seems a moderate tolerance to salinity and drought stresses. This knowledge will encourage effective methods for management tactics of S. elaeagnifolium.

Ambrosia artemisiifolia L. and Ambrosia trifida L. belong to allochthonous invasive weeds species. They cause great damage in colonized areas because they reduce the yield of agricultural crops, and also with their competitive abilities affect the suppression of other plants and thus affect the change of plant community. As Polygonum aviculare L. is one of the most common weeds on the European continent and a very common companion of rural and urban habitats, this study examined the impact of different ratios of A. artemisiifolia and A. trifida on the occurrence and abundance of P. aviculare. Presence P. aviculare was incereased in treatments with increasing A. trifida and decreased A. artemisiifolia/m2 .

Monoecious and dioecious forms of the submerged aquatic plant hydrilla, Hydrilla verticillata (Hydrocharitaceae) are invasive weeds in the United States. Monoecious hydrilla is expanding northward ...

A total of 16 different allergenic and invasive weed species belonging to 12 different families collected from different areas of study area. Among the studied plants, most of the species belong to the Asteraceae family. For morphological studies of pollen through LM and SEM the samples were acetalized. We done the fieldwork for the collection of weed plants and also performed the experimental work i.e. SEM and LM for the pollen morphology. Most of the species recorded with pollen of tricolporate and echinate. Species belonging to Asteraceae were considered as most abundant and allergenic as compared to others. The maximum polar diameter was noted in the Convolvulus arvensis is 40.00 µm and the minimum were noted in Oxalis corniculata is 6.15 µm. Maximum exine thickness was noted in convolvulus arvensis is 3.70 µm and Minimum were noted in Sorghum halepense is 1.65 µm. It was noticed that most of the allergenic and invasive weeds found in plain areas of Lakki Marwat during September and April. Present study provides information about the allergenic and invasive weeds plants and their threats to biodiversity. The pollen of such weed plants causes asthma and atopy disease in humans.

In the present study intercropping of two plant species was carried out over a soil contaminated with five heavy metals lead (Pb), cadmium (Cd), chromium (Cr), cobalt (Co) and nickel (Ni). The experimental setup was designed in such a manner that the effluent stream passed intermittently for 60 days through the plant species Acalypha indica and Amaranthus viridis grown on-site after which the species were uprooted and processed further to check the heavy metal concentration in several parts of the plant such as roots, stem, leaves and flowers as well as the soil. The flowers of A. indica accumulated a maximum amount of Pb and least in the stem with a Translocation Factor (TF) of 21.49 and a Bioconcentration Factor (BCF) value of 2 and the highest concentration of Cr in flowers followed by leaves, root and stem regions with a TF of 11.5 and BCF value of 244.59. Co accumulation in A. indica was noted to be maximum in the flowers and least in the stem with a TF of 12.03 and a BCF value of 3.77, while it was highest in the flowers and least in the root with 8.2 and 0.9 TF and BCF values respectively, for Cd, whereas for Ni it was highest in the flowers and least in stem with 18.19 TF and 11.04 BCF. A. viridis accumulated maximum amount of Pb in leaves followed by flowers and least in stem with a TF of 8.64 and BCF of 259.93. It accumulated highest amount of Cr in the leaves followed by flowers, stem and root region with a TF of 10.55 and BCF of 212.49. The leaves of A. viridis accumulated a maximum amount of Co and the least in the stem region with a TF of 7.05 and BCF of 4.95 while the concentration of Cd was highest in leaves and least in roots with 18.37 and 1.61 TF and BCF respectively. A. viridis accumulating trend for Ni was leaves > flowers > root > stem with a TF of 8.15 and BCF of 10.48. Hence as per the values obtained both the species exhibited successful phytoextraction of all the five heavy metals in their aerial parts making both of them good bioaccumulator species.

La présente étude a pour objectif de faire l’état des connaissances traditionnelles endogènes relatives aux plantes locales utilisées contre les bio-agresseurs des cultures et des produits agricoles. A travers une série d’enquêtes ethnobotaniques réalisée de 2018 à 2019 dans la région des Cascades au Burkina Faso, 150 personnes appartenant à l’ethnie Turka ont été interviewées. Les informations recherchées en utilisant des entretiens semi-directifs, ont concerné les noms locaux des plantes, les parties utilisées, les domaines d’utilisation et leurs modes d'utilisation. Les données collectées ont permis de recenser 33 espèces de plantes réparties en 30 genres et 19 familles utilisées traditionnellement contre les bio-agresseurs agricoles. Ces plantes interviennent sélectivement dans trois domaines : la répulsion des insectes, l’inhibition des herbes envahissantes et la construction des greniers. Les espèces sont utilisées soit directement ou transformées en poudre ou en cendre. Les feuilles sont plus utilisées que les autres organes. Cassia nigricans est l’espèce la plus utilisée pour son effet répulsif et Parkia biglobosa pour son effet inhibiteur. Des études approfondies sur les propriétés chimiques des potentielles espèces permettront de réduire l’impact des produits chimiques en agriculture contre les bio-agresseurs.Mots clés : Ethnobotanique, diversité végétale, ennemi agricole, secteur sud-soudanien, Afrique de l’ouest English Title:Traditional knowledge of local plants used against pests of crops and agricultural products among the Turka poeple in Burkina Faso The objective of this study is to provide an overview of endogenous traditional knowledge relating to local plants used against pests of crops and agricultural products. Through an ethnobotanical’s surveys carried out from 2018 to 2019 in the Cascades area in Burkina, 150 Turka ethnic group people were interviewed. Through semi-structured interviews, information looking for were concerned plants local names, their parts used, the domains and the modes of use. Data collected allowed to identify 33 plants’ species belonged to 30 genera and 19 families, used traditionally against agricultural pests. These plants are selectively involved in three domains: repelling insects, inhibiting invasive weeds and building lofts. Species are used either directly or processed into powder or ash. The leaves are used more than other organs. Cassia nigricans is the most used species for its repellent effect and Parkia biglobosa for its inhibitory effect. In-depth studies on the chemical properties of potential species will reduce the impact of chemicals in agricultural against pests.Keywords: Ethnobotany, plant diversity, agricultural pest, South Sudanese sector, West Africa

Polyploidy is a pervasive and recurring phenomenon across the tree of life, which occurred at variable time scales, ecological amplitudes and cell types, and is especially prominent in the evolutionary histories of plants. Importantly, many of the world's most important crops and noxious invasive weeds are recent polyploids. Polyploidy includes two major types, autopolyploidy, referring to doubling of a single species genome, and allopolyploidy referring to doubling of two or more merged genomes via biological hybridization of distinct but related species. The prevalence of both types of polyploidy implies that both genome doubling alone and doubling coupled with hybridization confer selective advantages over their diploid progenitors under specific circumstances. In cases of allopolyploidy, the two events, genome doubling and hybridization, have both advantages and disadvantages. Accumulated studies have established that, in allopolyploidy, some advantage(s) of doubling may compensate for the disadvantage(s) of hybridity and vice versa, although further study is required to validate generality of this trend. Some studies have also revealed a variety of non-Mendelian genetic and genomic consequences induced by doubling and hybridization separately or concertedly in nascent allopolyploidy; however, the significance of which to the immediate establishment and longer-term evolutionary success of allopolyploid species remain to be empirically demonstrated and ecologically investigated. This review aims to summarize recent advances in our understanding of the roles of hybridization and genome doubling, in separation and combination, in the evolution of allopolyploid genomes, as well as fruitful future research directions that are emerging from these studies.

Climate change is predicted to increase the frequency and impact of plant invasions, creating a need for new control strategies as part of mitigation planning. The complex interactions between invasive plants and biocontrol agents have created distinct policy and management challenges, including the effectiveness and risk assessment of biocontrol under different climate change scenarios. In this brief review, we synthesize recent studies describing the potential ecological and evolutionary outcomes for biocontrol agents/candidates for plant invaders under climate change. We also discuss potential methodologies that can be used as a framework for predicting ecological and evolutionary responses of plant-natural enemy interactions under climate change, and for refining our understanding of the efficacy and risk of using biocontrol on invasive plants.

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 inva...

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.

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 biolog...

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.

The invasive weed Asystasia gangetica was investigated for its potential as a biomonitor and as a phytoremediator of potentially toxic metals (PTMs) (Cd, Cu, Ni, Pb, and Zn) in Peninsular Malaysia owing to its ecological resistance towards unfavourable environments. The biomonitoring potential of PTMs was determined based on the correlation analysis of the metals in the different parts of the plant (leaves, stems, and roots) and its habitat topsoils. In the roots, the concentrations (mg/kg dry weight) of Cd, Cu, Ni, Pb, and Zn ranged from 0.03 to 2.18, 9.22 to 139, 0.63 to 5.47, 2.43 to 10.5, and 50.7 to 300, respectively. In the leaves, the concentrations (mg/kg dry weight) of Cd, Cu, Ni, Pb, and Zn ranged from 0.03 to 1.16, 7.94 to 20.2, 0.03 to 6.13, 2.10 to 21.8, and 18.8 to 160, respectively. In the stems, the concentrations (mg/kg dry weight) of Cd, Cu, Ni, Pb, and Zn ranged from 0.03 to 1.25, 5.57 to 11.8, 0.23 to 3.69, 0.01 to 7.79, and 26.4 to 246, respectively. On the other hand, the phytoremediation potential of the five metals was estimated based on the bioconcentration factor (BCF) and the translocation factor (TF) values. Correlation analysis revealed that the roots and stems could be used as biomonitors of Cu, the stems as biomonitors of Ni, the roots and leaves as biomonitors of Pb, and all three parts of the plant as biomonitors of Zn. According to the BCF values, in the topsoil, the “easily, freely, leachable, or exchangeable” geochemical fractions of the five metals could be more easily transferred to the roots, leaves, and stems when compared with total concentrations. Based on the TF values of Cd, Ni, and Pb, the metal transfer to the stems (or leaves) from the roots was efficient (&gt, 1.0) at most sampling sites. The results of BCF and TF showed that A. gangetica was a good phytoextractor for Cd and Ni, and a good phytostabilizer for Cu, Pb, and Zn. Therefore, A. gangetica is a good candidate as a biomonitor and a phytoremediator of Ni, Pb, and Zn for sustainable contaminant remediation subject to suitable field management strategies.

Parthenium hysterophorus L. is one of the most invasive weeds and belongs to the family Asteracaeae.

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.

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.

Three main Ambrosia species (Ragweed)grow in Israel of which A. artemisiifolia and A. tenuifolia are of restricted distribution and the invasive A. confertiflora is the most abundant and widely distributed in roadsides, open land, waterways and cultivated fields and orchards. The present research was aimed to study the effect of temperatures regimes on the development and growth of the three main Ambrosia species in Israel, to elucidate the environmental conditions and plant traits that affect their development and infestation patterns. Seed germination studies were conducted in petri dish and pots. Ambrosia spp. plant emergence and development kinetics of different organs were conducted in pots and trays in a net house and at different temperature regimes in a phytotron. A. confertiflora, A. artemisiifolia and A. tenuifolia 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 (28-34oC), A. artemisiifolia at low temperature regimes (10-16oC) C, while A. tenuifolia is less affected by the temperature regimes. A. confertiflora plant height increased with increasing temperatures, and at lower temperatures develops a rosette. Root and rhizome biomass was less affected by the different temperatures regimes, A. artemisiifolia overground mass was not affected by temperature regimes while A. tenuifolia overground mass was reduced only at lower temperatures. The factors affecting A. confertiflora fast invasion and establishment are: easy long-distance seed dissemination, prolific seed germination and sprouting of rhizomes, rapid growth, massive viable seed fecundity, and adaptation to changing and adverse environmental conditions.

Thermogravimetric analysis of two invasive weeds Prosopis juliflora (PJ) and Lantana camara (LC) are carried out by pyrolysis under dynamic conditions (20 to 900 °C) at different heating rates 5, 10, 20 and 40 °C/min. Gross calorific values of PJ and LC are estimated to 18.2 and 18.92 MJ/kg respectively. Activation energy obtained by FRM, M-FRM, KAS, OFW, STR, NL-INT, NL-DIF methods are 157.56, 151.24, 140.86, 143.39, 140.74, 141.19, 157.59 kJ/mol for PJ and 169.98, 167.67, 149.39, 151.51, 149.23, 149.70, 169.98 kJ/mol for LC respectively. Kinetic compensation effects were well fitted with the experimental data, which provided the value of the pre-exponential factor. To identify the appropriate reaction mechanism, the Popescu and Master-plot methods are employed. Thermodynamic parameters (ΔG, ΔH, and ΔS) are also determined by NL-INT, NL-DIF, and M-FRM methods. Results of kinetic and thermodynamic parameters confirm the suitability of PJ and LC invasive weeds as potential biomasses for pyrolysis process.

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.

Invasive aquatic macrophytes in Lake Victoria including water hyacinth (Eichhornia crassipes) exhibit periodic cyclical patterns of decline and proliferation with attendant ecological and economic impacts. This study aimed to monitor the extent of macrophytes and other invasive weeds on Lake Victoria to establish their impact on fisheries. The study employed a combination of remote sensing and geographical information system (GIS) techniques to estimate the coverage of water hyacinth and other invasive macrophytes. Data on fish landings and their respective market values were acquired from the Electronic Fish Market Information Service (EFMIS) database, which is hosted by the Kenya Marine and Fisheries Research Institute (KMFRI). Analysis of consistent temporal satellite data showed that the weeds frequently cover sheltered bays and river mouths. These areas of Winam Gulf had higher coverage (average 5000 ha) of macrophytes than the open waters (

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 biolo...

This study attempts to measure the growth of invasive plant species Mikania micrantha Kunth, which is considered as one among the top hundred worst invasive weeds worldwide. Seedlings of Mikania micrantha were propagated through vegetative part as well as seed for the study. The juvenile plants were allowed to grow on different hosts such as poles (nonliving support) and a garden plant (living support) in a soil that contains minimum requirements for growth. Growth of the seedlings was recorded daily by measuring the length of the stem, a number of twines and number of leaves for a growth period of fourteen days. The plants thrived on both types of support. The growth rate was higher in vegetatively propagated plants. It ensures re-growth even from a single node and is responsible for successful invasion of the weed after mechanical weeding.

Ageratina adenophora is one of the major invasive weeds that causes instability of the ecosystem. Research has reported that A. adenophora produces allelochemicals that inhibit the growth and development of food crops, and also contain some toxic compounds that cause toxicity to animals that consume it. Over the past decades, studies on the identification of major toxic compounds of A. adenophora and their toxic molecular mechanisms have been reported. In addition, weed control interventions, such as herbicides application, was employed to reduce the spread of A. adenophora. However, the development of therapeutic and prophylactic measures to treat the various A. adenophora—induced toxicities, such as hepatotoxicity, splenotoxicity and other related disorders, have not been established to date. The main toxic pathogenesis of A. adenophora is oxidative stress and inflammation. However, numerous studies have verified that some extracts and secondary metabolites isolated from A. adenophora possess anti-oxidation and anti-inflammation activities, which implies that these extracts can relieve toxicity and aid in the development of drug or feed supplements to treat poisoning-related disorders caused by A. adenophora. Furthermore, beneficial bacteria isolated from rumen microbes and A. adenophora can degrade major toxic compounds in A. adenophora so as to be developed into microbial feed additives to help ameliorate toxicity mediated by A. adenophora. This review presents an overview of the toxic mechanisms of A. adenophora, provides possible therapeutic strategies that are available to mitigate the toxicity of A. adenophora and introduces relevant information on identifying novel prophylactic and therapeutic measures against A. adenophora—induced toxicity.

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.

African para grass (Urochloa mutica) is an invasive weed that has become prevalent across many important freshwater wetlands of the world. In northern Australia, including the World Heritage landscape of Kakadu National Park (KNP), its dense cover can displace ecologically, genetically and culturally significant species, such as the Australian native rice (Oryza spp.). In regions under management for biodiversity conservation para grass is often beyond eradication. However, its targeted control is also necessary to manage and preserve site-specific wetland values. This requires an understanding of para grass spread-patterns and its potential impacts on valuable native vegetation. We apply a multi-scale approach to examine the spatial dynamics and impact of para grass cover across a 181 km2 floodplain of KNP. First, we measure the overall displacement of different native vegetation communities across the floodplain from 1986 to 2006. Using high spatial resolution satellite imagery in conjunction with historical aerial-photo mapping, we then measure finer-scale, inter-annual, changes between successive dry seasons from 1990 to 2010 (for a 48 km2 focus area), Para grass presence-absence maps from satellite imagery (2002 to 2010) were produced with an object-based machine-learning approach (stochastic gradient boosting). Changes, over time, in mapped para grass areas were then related to maps of depth-habitat and inter-annual fire histories. Para grass invasion and establishment patterns varied greatly in time and space. Wild rice communities were the most frequently invaded, but the establishment and persistence of para grass fluctuated greatly between years, even within previously invaded communities. However, these different patterns were also shown to vary with different depth-habitat and recent fire history. These dynamics have not been previously documented and this understanding presents opportunities for intensive para grass management in areas of high conservation value, such as those occupied by wild rice.

An invasive weed is a nonnative plant that exhibits rapid population growth following its arrival in a new environment where it did not evolve. The success of the weed in its new habitat is due in part to the absence of the natural enemies that normally limit its reproduction and spread in its native range. Classical biological control seeks to reunite an invasive weed with one or more of its co-evolved natural enemies to provide permanent control of the weed. This document is ENY-828, one of a series of the Department of Entomology and Nematology, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Published: May 2005. ENY-828/IN607: How Scientists Obtain Approval to Release Organisms for Classical Biological Control of Invasive Weeds (ufl.edu)

Lygodium microphyllum (Cav.) R.Br. (Old World climbing fern) and L. japonicum (Thunb.) Sw. (Japanese climbing fern), in the family Schizaeaceae, are among the most invasive weeds in Florida (1). L. microphyllum invades fresh water and moist habitats in south Florida, while L. japonicum has spread in relatively well-drained habitats from Texas to North Carolina and central Florida. Some potted plants of both Lygodium spp. grown in shadehouse as well as in full sunlight developed discolored spots on pinnules (foliage), which coalesced and resulted in browning and dieback of severely infected vines. Symptomatic foliage obtained from these plants was surface-sterilized by immersing in a 15% solution of commercial bleach for 90 s, followed by a series of four rinses with sterile deionized distilled water. Disks (4 mm in diameter) of pinnules were cut from the junction of discolored and healthy tissues and placed on potato dextrose agar (PDA). A fungus, Colletotrichum gloeosporioides (Penz.) Penz. & Sacc. was consistently isolated from these disks. Fungal colonies produced abundant conidia on PDA. Conidia were hyaline, straight, cylindrical, averaging 14.7 μm (range 12.5 to 17.5 μm) × 5.0 μm (range 3.8 to 7.5 μm), and similar to those described for C. gloeosporioides (2). To confirm the pathogenicity of C. gloeosporioides on L. microphyllum and L. japonicum, Koch's postulates were performed. A fungal isolate was grown on PDA for 3 weeks, after which 10 ml of sterile deionized distilled water was added to the culture and agitated to dislodge conidia. The conidial suspension was strained through three layers of cheesecloth to remove hyphal fragments, and its concentration was adjusted to 1.7 × 106 conidia/ml. Foliage of healthy L. microphyllum and L. japonicum plants grown in 500-ml containers was sprayed with the conidial suspension until runoff. Plants were covered with plastic bags whose inner sides were misted with water to maintain high humidity and placed in a growth chamber under 12 h of fluorescent light per day. Temperature and relative humidity in the chamber ranged from 26 to 29°C and 44 to 73%, respectively. Plastic bags were removed after 3 days, and plants were further incubated for 3 weeks in the same growth chamber. Control plants were sprayed with sterile water, covered with plastic bags, and exposed to the same temperature, light, and humidity regime as those of the fungus-inoculated plants. Small, discolored foliar spots appeared 3 days after fungus inoculation. These spots were similar to those observed on pinnules of potted plants that originated from shadehouse and outdoor environments. Within 3 weeks after inoculation, the foliage of L. japonicum developed abundant discolored spots that led to edge browning and wilting of the pinnules. L. microphyllum had similar but more severe symptoms, with plants suffering as much as 50% dieback. C. gloeosporioides was consistently reisolated from the symptomatic tissues of both fern species. No symptoms appeared on the water-inoculated plants. To our knowledge, this is the first record of C. gloeosporioides pathogenicity on L. microphyllum and L. japonicum. References: (1) R. W. Pemberton and A. P. Ferriter. Am. Fern J. 88:165, 1998. (2) B. C. Sutton. Colletotrichum: Biology, Pathology and Control. CAB International, Wallingford, Oxon, UK, 1992.

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 iverse 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. Refereed/Peer-reviewed

Three Asian leaf beetles of the genus Chrysochus were investigated as potential biological control agents of Vincetoxicum rossicum and V. nigrum, invasive weeds in northeastern North America. Chrysochus chinensis and Ch. globicollis were collected from a field host in a different genus and subtribe. Preliminary no-choice laboratory tests with Ch. goniostoma showed that its physiological host range is too broad. Based on these data, we are not considering these three species as potential biological control agents of invasive Vincetoxicum species.

Summary The effective control of highly invasive weeds in Australia is an important conservation management action. In this study, we monitored the outcome of herbicide control on high-threat weeds in the wet forests of the Central Highlands of Victoria. Twenty-two control (no weed control) and 32 treatment (weed control) plots were surveyed annually over 24 months. Initial results show that weed cover and frequency decreased substantially in response to weed control; however, it is too early to determine the response of native species. We recommend that herbicide control and the associated monitoring programme be continued, and depending on the outcomes, data should be used to develop a more integrated management strategy.

Aquatic ecosystems in Botswana have been under threat by the aquatic alien invasive plant species viz., salvinia Salvinia molesta Mitchell, water lettuce Pistia stratiotes L., and water hyacinth Eichhornia crassipes (Mart.) Solms-Laub. While salvinia has been termed the major threat to the Botswana wetlands, water lettuce and water hyacinth are considered to be of minor importance. This review presents the species biology, distribution, historical spread, negative impacts, control achieved right from their discovery in the country by referring to their control and management in the world. Having infested the Kwando-Linyanti-Chobe Rivers in the 1970s, salvinia was initially tried by the use of herbicides, paraquat and glyphosate, between 1972 and 1976. With the discovery of the host specific biological control weevil Cyrtobagous salviniae Calder and Sands in 1981, the weevil was introduced by Namibians on Kwando and Chobe Rivers in 1983 and by Botswana in 1986 in the Okavango Delta. While the control was slowly establishing in Kwando-Linyanti-Chobe Rivers, it became apparent that lakes and perennial swamps within and outside Moremi Game Reserve of the Okavango Delta were infested with salvinia from 1992 onwards. With continuous and sustained liberation of the weevil in the Kwando-Linyanti-Chobe Rivers and in the Okavango Delta between 1999 and 2000, salvinia control was achieved by 2003, and since then the weevil constantly keeps the weed at low levels. The success is mainly due to sustainable monitoring through the application of physical and biological control methods. However, salvinia is still threatening the Okavango Delta due to factors such as tourism activities, boat navigation fishing and transporttion by wild animals. The first occurrence of water lettuce was recorded on Kwando and Chobe Rivers in 1986. Its biocontrol weevil Neohydronomous affinis Hustache was released in the year 1987. The weevil became extinct in Selinda Canal and Zibadianja Lake on Kwando River due to dry and wet events for over 10 years and the weed had been under control biologically on Chobe River. Having surface covered the Selinda and a part of the Zibadianja in high flood and rainfall in 1999/2000 season, research was undertaken to contain water lettuce, which led to its eradication by 2005. Regular physical removal of the water lettuce prior to fruit maturity is an effective method of control or eradicating the weed in seasonal water bodies. The Limpopo Basin (shared by Botswana, South Africa, Zimbabwe and Mozambique) has become vulnerable to water hyacinth infestation. Water hyacinth infested the trans-boundary Limpopo River in 2010 sourced from Hartbeesport Dam on Crocodile River in South Africa. Botswana and South Africa have been consulting each other to implement integrated control of the weed jointly in the Limpopo River. Water hyacinth could be a continuous threat to the dams and the rivers in the Limpopo basin if its control is not taken seriously. These three species are found growing in Botswana in a range of pH between 4.5 and 10.3 and in the range of conductivities between 20 and 580 µS cm-1. Range of soluble nitrates, phosphates and potassium in the habitats of salvinia infestations were 0.02 to 1.5, 0.01 to 1.78 and 0.3 to 6.92 mg L-1 respectively. Water lettuce infestation in the seasonal Selinda Canal had a maximum of 4.7 mg L-1 nitrates, 2.8 mg L-1 phosphates and 7.9 mg L-1 potassium. Nevertheless, these three nutrients were in the range of 0.41 to 9.56 mg L-1, 0.2 to 2.9 mg L-1, and 7.7 to 11.53 mg L-1 respectively in the Limpopo River where water hyacinth infestations were observed. These nutrients were considerably high during decomposition phase of biological control of weeds. The Government of Botswana “regulates the movement and importation of boats and aquatic apparatus, to prevent the importation and spread of aquatic weeds both within and from the neighboring countries” by “Aquatic Weed (Control) Act” implemented in 1986. These measures, combined with communities, conservation groups, NGOs and public awareness campaigns, have highlighted the gravity of aquatic weeds spreading into wetlands, dams and other water bodies. In conclusion, the Government of Botswana is committed and supportive through the Department of Water Affairs in protecting the wetlands of the country efficiently and prudently.

Surveillance tasks of weeds and vegetation in arid lands is a complex, difficult and time-consuming task. In this article we present a framework to detect and map invasive grasses, combining UAVs and high-resolution RGB technologies and machine learning for data processing. This approach is illustrated by segmenting Buffel Grass (Cenchrus ciliaris) and Spinifex (Triodia sp.), Segmentation results produced individual detection rates of 97% for buffel grass, 96% for spinifex and 97% for the overall classification task. The algorithm is robust against variations in illumination, occlusion, object rotation and density of vegetation.

Aroeira ou pimenta rosa, Schinus terebinthifolia Raddi (Anacardaceae), planta nativa da Argentina, Brasil, Paraguai e Uruguai é uma das plantas daninhas mais invasivas na Flórida. Em sua região de origem, pelo menos 4 espécies de psilídeos do gênero Calophya (Hemiptera: Calophyidae) estão associados a esta planta. Todas as quatro espécies são monófagas e provavelmente constituem um grupo monofilético que induzem galhas lenticulares abertas, usualmente na face superior da folha. Aqui a taxonomia das 4 espécies é revisada, 2 das quais são descritas como novas, C. lutea sp. nov. e C. praestigiator sp. nov. Diferenças morfológicas entre as 4 espécies são detalhadas e estruturas relevantes são ilustradas. Fornecemos chave para identificação de adultos e imaturos de quinto instar para as 8 espécies conhecidas como indutoras de galhas em espécies de Schinus. Made available in DSpace on 2018-06-29T01:37:13Z (GMT). No. of bitstreams: 1 2018DalvaFETaxonomy.pdf: 14574224 bytes, checksum: bdd91c2158f8f36e9cc15403aec50352 (MD5) Previous issue date: 2018-06-28

We completed chloroplast genome of Dysphania pumilio (R.Br.) Mosyakin & Clemants isolated in Anyang city in Korea. Its length is 151,960 bp consisting four subregions: 83,756 bp of large single cop...

Adding product value to the invasive weeds may prove to be an effective way for weed management. In this study, we used Lantana camara L and Parthenium hysterophorus weeds as model systems to investigate as heat transfer biofluids for their potential application in heat transfer industries. We also compared the thermal conductivity results of these two weeds based biofluids with various nanofluids. The thermal conductivity enhancement in L. camara L is much higher than that in P. hysterophorus. The thermal conductivity of L. camara L and P. hysterophorus biofluids was found to be higher than that of various nanoparticles based nanofluids. These observations suggest that weeds can be utilized as coolants for heat transfer industries leading to an advantageous reduction in the overall consumption of water used in various industries. Moreover, this value addition will provide an economically-optimal new outlook for weed management strategy.

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.

The paper presents a novel and universally applicable strategy to rapidly screen and identify non-target flavonoid components in invasive weeds by liquid chromatography hybrid ion trap time-of-flight mass spectrometry. This strategy consists of three steps of data processing including the diagnostic fragment ion (DFI) determination, the flavonoid component screening out based on the extracted ion chromatograms of DFIs and the final validation via manual fragment comparison. The main advantages of this strategy are the complete non-target or semi-target identification and simplifying the complicated procedures of structural characterization by rapidly classifying the peaks into well-known chemical families. The flavonoid identification strategy was validated to be very useful and powerful for the identification of flavonoid components in three invasive weeds Flaveria bidentis (L.) Kuntze, Mikania micrantha Kunth and Solanum rostratum Dunal. Using this approach, a total of 17 flavonoid components have been detected rapidly and identified in Flaveria bidentis (L.) Kuntze, ten of which were in accordance with those in our previous publication using manual analysis; moreover, 7 new flavonoid components were also detected. This developed strategy is highly efficient and would be widely applicable to the component identification of other complex matrices like biological, alimental or environmental sources.

Both spiny and edible amaranths (Amaranthus spinosus and A. tricolor) are exotic annuals in China that produce numerous small seeds every year. Spiny amaranth has become a successful invader and a troublesome weed in Xishuangbanna, but edible amaranth has not, although it is widely grown as a vegetable there. As seed germination is one of the most important life-stages contributing to the ability of a plant to become invasive, we conducted experiments to compare the effects of high temperature and water stress on seed germination in two varieties each of spiny amaranth and edible amaranth. Overall, the seeds of both amaranth species exhibited adaptation to high temperature and water stress, including tolerance to ground temperatures of 70°C for air-dried seeds, which is consistent with their behavior in their native ranges in the tropics. As expected, the invasive spiny amaranth seeds exhibited higher tolerance to both continuous and daily periodic high-temperature treatment at 45°C, and to imbibition-desiccation treatment, compared to edible amaranth seeds. Unexpectedly, edible amaranth seeds exhibited higher germination at extreme temperatures (10°C, 15°C, and 40°C), and at lower water potential (below -0.6 MPa). It is likely that cultivation of edible amaranth has selected seed traits that include rapid germination and germination under stressful conditions, either of which, under natural conditions, may result in the death of most germinating edible amaranth seeds and prevent them from becoming invasive weeds in Xishuangbanna. This study suggests that rapid germination and high germination under stress conditions-excellent seed traits for crops and for many invasive species-might be a disadvantage under natural conditions if these traits are asynchronous with natural local conditions that support successful germination.

It has been more than seven decades since the first data on the presence of common ragweed (Ambrosia artemisiifolia) in Bosnia and Herzegovina was published. The literature data show that this invasive weed species has spread and became naturalized in a major part of Bosnia and Herzegovina, and has a tendency of further spreading. It is believed that was introduced from the north and spread towards the south. Depending on the weather conditions, common ragweed occurs predominantly during the mid-spring and produces inflorescences from July until the first frost. The common ragweed plants can grow to be over 2 meters high. This species is very adaptive to different environmental conditions, and its fast expansion in the area of Bosnia and Herzegovina was favored by the increase of areas under uncultivated and abandoned land after the war. Since common ragweed is harmful both as a weed species and as an allergenic plant dangerous to human health, it is necessary to take all available measures to prevent its further spread, but also to reduce the number of populations in the areas where it is already established. Key words: common ragweed, invasive weeds, Bosnia and Herzegovina Pred vec kot 70 leti so bili objavljeni prvi podatki o pojavu ambrozije (Ambrosia artemisiifolia) v Bosni in Hercegovini. Literaturni podatki kažejo, da se je ta invazivna vrsta razsirila in postala obicajna v vecjem delu Bosne in Hercegovine in kaže da se bo sirila se naprej. Velja prepricanje, da je bila uvedena in se sirila od severa proti jugu. Odvisno od vremenskih razmer se ambrozija pojavlja predvsem sredi pomladi in se na njej razvijajo socvetja od meseca julija do prve slane. Rastline ambrozije lahko zrastejo do visine preko 2 m. Vrsta se zelo prilagaja razlicnim okoljskim razmeram, k njenemu sirjenju na obmocju Bosne in Hercegovine je prispevalo v casu vojne tudi sirjenje neobdelanih in zapuscenih zemljisc. Ker je ambrozija skodljiva tako kot plevelna rastlina, kot rastlina, ki povzroca alergije in skoduje zdravju ljudi, je nujno izvajati ukrepe za preprecevanje nadaljnjega sirjenja. Zelo pomembno pa je tudi zmanjsevanje stevila rastlin v populacijah, kjer je že razsirjena. Kljucne besede: ambrozija, invazivni pleveli, Bosna in Hercegovina

The ability of plants to colonize new habitats is influenced by their dependence on effective pollinators. This can be very important for plants that require specialized pollinators, especially when they disperse to islands that have low pollinator diversity. One form of specialization involves plants that require buzz-pollination, where bees must vibrate poricidal anthers at frequencies that allow pollen to be released. Pollen larceny is a phenomenon where insects ‘steal’ pollen from flowers which usually results in reduced pollination, but in some cases there can be a small contribution to pollination. Here we report pollen larceny in an endemic Fijian halictine bee Homalictus fijiensis that steals pollen by chewing anthers of the invasive weed Solanum torvum, which is a pollen-only plant requiring buzz pollination. In over nine hours of observations at six sites where H. fijiensis visited S. torvum, it never attempted to locate nectaries, it never buzzed anthers, and instead chewed anther tips, indicating an adaptation to exploit nectarless flowers with poricidal anthers without buzz-pollination. Analyses of 30 pollen loads from H. fijiensis collected from S. torvum flowers indicate 27 of these contained S. torvum pollen, ranging from 1% to 99% of total pollen, indicating it is a pollen vector for this plant. Our findings support arguments that super-generalist pollinators in island ecosystems can promote the spread of invasive plants, but go further by indicating that super-generalist strategies can extend to plants with highly specialized pollinator requirements.

One of the lakes in Ethiopia knows as Lake Tana. It is located in Amhara regions the capital city of Bahar Dar town. In this lake in the resent year the very series problem in the areas know as Water hyacinth. Water hyacinth the distribution and abundance increase the current time and also strongly decreased water quality and intensity of aquatic biodiversity in the Lake. The objective of the review was the impact of water hyacinth, Eichhornia crassipes (Martius) Pontederiaceae) in Lake Tana Ethiopia. Water hyacinth in the lack and nearby the areas the local community its impact on series environmental problem and its influenced aquatics biodiversity. At present Water hyacinth (Eichhornia crassipses) have been first position as one of the worldwide most terrible invasive weeds source harms to millions of consumer of water resources.

Three weedy grasses, Echinochloa crus-galli (L.) P. Beauv. Echinochloa colona (L.) Link. and Echinochloa stagnina (Retz.) P. Beauv. were grown for four months in the greenhouse of Botany Department , Faculty of Science at New Damietta to examine the effect of age on plant biomass, ash, proteins, total carbohydrates, lipids and fiber content. Plants were collected from the field and replanted in greenhouse, with the same age and size. Biomass and ash content increased by increasing the age in E. colona and E. stagnina but increased in E. crus-galli till the fourth harvest then decreased. Protein, crude lipid and crude fiber content were decreased gradually by the increase of the age, in the three species throughout the progressive harvests. By the increase of the age total carbohydrates increased in E. crus-galli and E. colona but remained largely unchanged in E. stagnina . The crude fiber was a relatively high in E. crus-galli and E. colona but this was not good for forage use of the grass. The amount of PEPC and Rubisco protein was higher in E. stagnina than in E. crus-galli and E. colona and this lead to increase in plant biomass of E. stagnina than E. crus-galli and E. colona . It is recommended using E. stagnina as fodder additives due to its high content of protein and biomass and low fiber content. The obtained results will be useful for the optimum managing strategy of these three grasses as invasive weeds in field crop as well as use them as a source of natural forage in particular in summer.

Plant-mediated indirect interactions among herbivores (arthropods and pathogens) are common and extensively reported in the ecological literature. However, they are not well-documented with respect to weed biological control. Such interactions between biological control agents can have net positive or negative impacts on total weed suppression depending on the strength of the interaction(s), the relative importance of the agent indirectly impacted, and the combined weed suppression that results. A better understanding of plant-mediated interactions may improve decision-making about which agents to introduce in classical biological control programs for greatest impact on invasive weeds. This paper reviews the subject, including examples from the biological control literature; outlines the need for research on indirect effects of herbivores on other herbivores; discusses how such knowledge may strengthen classical biological control programs for invasive weeds; and provides recommendations for the kind of studies that should be done and how information about plant-mediated interactions could be integrated into agent evaluation protocols, to assist in decision-making about agents for importation and release.

Lantana camara is a widespread exotic invasive species in India, capable of dominating and displacing native forage species. We investigated whether L. camara was associated with variation in elephant foraging behavior in Mudumalai Tiger Reserve, India. The behavioral responses of elephants to L. camara were assessed from feeding and stepping rates. Elephants were never observed to feed on L. camara, but rather fed on grass and browse present within and around L. camara patches. A multiple regression analysis showed that feeding rates were negatively associated with L. camara invasion (F1, 55 = 4.26, R 2 = 0.07), but not stepping rates. Instead, grass cover and browse density were associated with stepping rates (F2, 55 = 11.16, R 2 = 0.30). Path analysis indicated that the total effect of L. camara on feeding rates was 11 percent (b = 0.24) less than the direct negative association (b = 0.27) owing to a positive indirect association of L. camara with feeding rates through grass cover and browse density (b = 0.03), while stepping rates were negatively associated with grass cover (b = 0.39) and positively associated with browse density (b = 0.38). Our results indicate that L. camara appears capable of modifying feeding rates of elephants, likely through a loss of grass areas due to L. camara invasion. Experimental work is needed to test for causal relationships among the variables we measured, to enhance our understanding of how invasive weeds modify elephant behavior.