New European distribution of Coleosporium inulae (Coleosporiaceae) on Dittrichia graveolens (Asteraceae) and considerations for weed biological control

Invasive alien weeds pose a serious threat to the biodiversity of natural ecosystems and a significant constraint to agricultural production worldwide. The use of co-evolved natural enemies, a strategy referred to as classical biological control (CBC), has proven to be a potentially efficacious, cost-effective, and safe option for the management of alien weeds. An analysis of CBC of invasive weeds in Latin America is presented, which shows that only 5% of the worldwide releases of agents, overwhelmingly arthropod, have been in this region. Fungal pathogens are increasingly being considered in CBC programmes, and there are now 11 examples of Latin American fungi having been released as biocontrol agents in other regions of the world. In contrast, only three weed pathogens have been deliberately released in the region. Possible reasons for the paucity of CBC programmes in Latin America are presented, despite the presence of a significant number of alien weed species (60 are listed). An analysis of these weeds reveals that many of them could be amenable to control using natural enemies, including nine weed species for which CBC programmes have been successfully implemented elsewhere in the world. In addition, for many of these 60 species, a co-evolved and damaging mycobiota has already been recorded. The prospects for management of invasive alien weeds in Latin America, using co-evolved fungal pathogens, are assessed with particular reference to selected species from the genera Ambrosia, Broussonetia, Calotropis, Commelina, Cyperus, Dichrostachys, Echinochloa, Pittosporum, Rottboellia, Rubus, Sonchus and Ulex.

In addition to their impact on natural habitats, invasive alien plants can have a significant negative effect on agricultural systems and cause economic losses. Flood‐irrigated orchards in the Mediterranean Basin are vulnerable to the invasion of alien weeds, primarily because of the traditional management practices used in the orchards, which are characterized by high soil moisture during the dry summer period, nutrient availability and high levels of disturbance. This study sought to determine whether their biological traits can explain the success of alien weed species. To answer this question, 408 floristic relevés were conducted in 136 flood‐irrigated orchards on the Plains of Lleida (Catalonia, NE of Spain). Richness and cover of native and alien weeds were compared. Furthermore, a set of biological traits were compared between successful and non‐successful weeds for the whole data and separately between native and alien weeds using logistic regression and classification trees. In flood‐irrigated orchards, alien species covered most of their area, even though the richness of alien species was lower than that of the native species. The most important species wereC4species with seeds dispersed by water, and on the other hand, rosulate and caespitose‐reptant hemicryptophytes with long flowering period. Most of these traits fitted with those of the invasive alien weeds, which were mostlyC4species with seeds dispersed by water. Perennial life form characterized successful native weeds. In this study, we discuss how the traditional management of flood irrigation in fruit‐tree orchards favours invasive alien weeds that have specific traits, acting as a reservoir for the spread of alien weeds into other crops and surrounding riparian habitats. We also propose changing management practices in order to avoid the selection of alien weeds and to promote native species.

Invasive alien weeds are non-native organisms that cause potential harm to the environment, economics and human health. Its ability to outcompete native species for space, water, nutrients, and other essential resources, adaptability to a variety of environmental conditions, absence of natural predators and parasites and prolific seed producing characteristics, once established it is very difficult to control or eliminate. Eradication through utilization is the present concept of management of invasive alien weeds. Eichhornia crassipes (Mart.) Solms, Salvinia molesta D.S. Mitchell, Parthenium hysterophorus L., Mikania micrantha Kunth, Chromolaena odorata (L.), Mimosa invisa Mart. Ex Colla and Lantana camara L. are the major invasive alien weeds of Kerala. The literature about the bio-utilization of these major invasive alien weeds is reviewed in this paper.

Invasive alien weeds in Nepal have become a great problem. Many of them have been naturalized and threatening native ecosystems and biodiversity. This assessment was carried out to measure the density, frequency and coverage of four major invasive weeds in a historical place, Chobhar of Kathmandu, Nepal. It was found that Ageratina adenophora had the highest density, frequency, and cover in the Pine forest. Similarly, Ageratum conyzoides, Bidens pilosa, and Parthenium hysterophorus were dense and frequent with high cover along the roadside. The frequency of B. pilosa and P. hysterophorus was comparatively high in the fallow land. It shows that the ecological parameters of the particular invasive alien weeds vary with land-use types and aspects. These weeds should be regularly monitored and appropriate methods of controlling them should be implemented in the study area.

Invasive alien weeds are plant pests because they can interfere with the growth and productivity of surrounding plants. Studies of invasive alien weeds, inventory of species, and their dispersal are important not only in conservation environments but also in study areas in educational institutions such as universities. This research was conducted with the aim of being an initial study to determine the types and distribution vectors of invasive alien weeds in the study area of the biology garden of UIN Sunan Gunung Djati Bandung which have the potential to disrupt the surrounding ecosystem. Weed sampling was carried out by purposive sampling exploration method in the biology garden area of the Faculty of Science and Technology UIN Sunan Gunung Djati Bandung. Based on the inventory results, a total of 16 species and 8 families of invasive alien weeds were obtained with the most families coming from the Asteraceae family. The invasive alien weed seed dispersal vectors include wind, water, and animals. Most invasive alien weed species found in the sampling sites have wind and animal dispersal vector types (31.25%). Seed dispersal by animals and wind has an effective dispersal rate because the range of distribution is quite wide. In addition, the characteristics of seeds, the ability to adapt and develop in new environments in plants such as species of the Asteraceae family can cause their invasion to take place quickly and massively.

Plant species have been introduced increasingly into non-native ranges, where many have become exotic weeds with adverse impacts on native ecosystems, as well as on farming and other livelihoods. In biological control, the classical or inoculative approach is the one most commonly used for the management of invasive alien weeds and is based on the use of co-evolved natural enemies from the native range to control the invasive weed. Typically, the inundative or mycoherbicide approach targets problematic weeds using local plant pathogens that, in the case of introduced species, have 'jumped' onto the exotic host. The leaf-spot fungus, Mycosphaerella polygoni-cuspidati, co-evolved with its host, Reynoutria (Fallopia) japonica (Japanese knotweed), in Japan and has a unique history of being investigated both as a classical biological control agent and a mycoherbicide against this highly invasive weed in the United Kingdom and North America. Here, we highlight our research on M. polygoni-cuspidati as part of a biological control programme for Japanese knotweed and review the potential of mycoherbicides using exotic pathogens for the management of invasive alien weeds. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

South Asian region, like other regions of the world, is witnessing a rising problem of invasive alien weeds with wide ranging environmental and socio-economic impacts. Current policy and management responses, and national capacities of the South Asian countries are inadequate in slowing down the rate of invasion process, suggesting a need for new approaches to address the problem. Through narrative review of selected references and author’s own experiences, several challenges of invasive weed management in South Asia have been identified, including inadequate policy responses, ineffective quarantine and biosecurity rules, low national capacity, knowledge gaps on key aspects, and a lack of common and agreed standards for species categorization. Future prospects identified for effective management of invasive weeds in South Asia include improving awareness of invasive weeds problem among policy makers and other stakeholders, regional networking for information exchange, regional collaboration for biological control program, and regional collaboration among researchers to generate policy relevant information. In a nutshell, formulation of the South Asian Regional Strategy for Invasive Alien Species and its proper implementation will prevent introduction of new invasive weed species and control of established invasive weed species for the benefit of imperiled biodiversity, ecosystems and billions of people inhabiting in this region.

Weeds interference with crops and native useful plants, causing negative impacts on crop production and biodiversity. Weeds being more adaptable to changing climate establish easily into new areas becoming invasive over the native vegetation. To investigate further the adaptability of invasive weeds and their status among the native plant community a field survey was carried out from July – September, 2017 at New Developmental Farm (NDF), Malakandher, The University of Agriculture, Peshawar to record weeds species composition. Data was sampled from three different sites i.e. field crop area, non-field and orchards with a quadrate randomly thrown 50 times at different locations. A total of 39 weeds species from 16 families (14 dicot and two monocot) and 36 genera were identified. Dicots were dominant as compared to monocot. The major monocot family poaceae contributed 10 species while in dicots Asteraceae took the lead with 6 species, followed by Euphorbiaceae with 3 species. The rest of the plant families include Aizoaceae, Amaranthaceae, Convolvulaceae, Cucurbitaceae, Cyperaceae, Euphorbiaceae, Malvaceae, Nyctaginaceae, Oxidillaceae and Plantaginaceae. Among the weed species 27 were annual and the rest (12) were perennials. Annuals were reported from all the three sites, while perennials were found in non-field area i.e. irrigation canals, field ridges, orchards and undisturbed waste areas. Data regarding absolute and relative density, frequency, relative frequency and importance valve of weeds of the area were recorded by quadrate method. Cynodon dactylon had the highest relative density (27.21%), followed by Digiteria sanguinalis (14.87), Cyperus rotundus (12.96) and Euphorbia prostrata (5.12) relative density, respectively. Parthenium hysterophorus L. an invasive alien weed was recorded in almost all the localities with a weed density of 2.6 m-2 in non-field area especially, followed by 0.85 m-2 in field crop and 0.8 m-2 in orchards and with a mean density of 1.42 m-2 and a relative density % of 1.52 across all locations. Similarly another invasive weed Broussonetia papyrifera was recorded in non-field area only with lowest mean relative density of 0.07%. Mean distribution data showed highest relative frequency for C. dactylon (13.66 %) followed by D. sangunalis (10.22), C. rotundus (7.86) and S. halepense (7.23), respectively. Alhaji maurorum, Eclipta alba, Cucumis callosus, B. papyrifera, Withania somnifera and Boerhavia diffusa took the smallest relative frequency of 0.38 % at most of the locations studied thereby indicating them as insignificant among the weed flora of the study area. Importance value data revealed that C. dactylon, D. sangunalis, C. rotundus and S. halepense having IV % of 34.03, 19.99, 16.89 and 10.17, respectively. Looking at the overall distribution of weeds flora in NDF Malakandher during the summer season C. dactylon is distributed on road sides, field ridges, irrigation channels, agricultural fields, orchards and waste lands, while P. hysterophorus being an invasive weed showed increasing trend compared to its earlier status evident from previous study.

Emerging technologies such as high-resolution Unmanned Aerial Vehicles (UAVs) surveys combined with object-based image analysis, and field surveys could represent a reliable, precise, and effective tool to support land management in agricultural systems. The technological advances of UAVs can also promote the detection and regular monitoring of invasive alien plants and agricultural weeds. The objective of the study has been to identify, map and monitor alien weed species in agricultural systems to provide an overview of the future applications and challenges of precision farming. In particular, we evaluated how UAV imagery can be used to assess the cover of Oxalis pes-caprae, present in several crops in Sardinia as an alien invasive weed, with negative direct and indirect effects on the affected crops. Our core assumption is that the most reliable species discrimination can be achieved by targeting flights during flowering to allow easier detection due to species-specific spectral differences. Therefore, O. pes-caprae infestation was acquired using RGB camera installed on board a Phantom 4 pro. As a result, we presented the mapping of O. pes-caprae, highlighting the cost-effectiveness and replicability of this approach to detect the presence of this alien weed in agricultural fields.

Invasion by alien species threaten native biodiversity, alter the functioning of ecosystems, and cause substantial economic impacts. Biological control of these invasive species using co-evolved natural enemies has long been considered a safe, cost effective, and environmentally benign tool for pest management. Here, we for the first time report the Mediterranean endophagous seed beetle Bruchidius tuberculatus (Hochhut 1847) as a potential biocontrol agent of a noxious medicinal weed ‘Iberian starthistle’ Centurea iberica Trev. ex Spreng. This is also the first report of this bruichid from the Indian subcontinent, which accidentally got introduced into Kashmir Himalaya, perhaps as a seed contaminant. Adults of the species were bred from the flower heads of the invasive alien weed species. Grubs of the beetle were found to be efficient predispersal specialist seed feeders, exerting a substantial control on total viable seed output at natural population levels. As the narrower host range of endophagous species is a preferable weed control strategy, this Mediterranean bruchid seems to be a promising host specific biological control agent of the noxious weed. Key words: Centaurea iberica, Bruchidius tuberculatus, Biocontrol, Invasion.

INVASIVE EXOTIC SPECIES ARE A MAJOR ECOLOGICAL PROBLEM in many of the world's ecosystems (Sala et al. 2000). With some notable exceptions, however, most tropical moist forests appear to be resistant to the impacts of invasive exotic plants (Rejmainek 1996, Denslow & DeWalt in press). Sala et al. (2000), for example, identified land use change, but not biotic exchange, as the major threat to tropical ecosystems. However, the impacts of invasive exotic plants are a leading threat to native ecosystems on oceanic islands, where naturalized exotic plants have doubled the sizes of floras (Sax et al. 2002). On tropical islands, exotic species invade intact forests, alter successional trajectories, impede restoration of endangered plant communities, and contribute to the degradation of fragmented ecosystems (Denslow & DeWalt in press). These impacts are of special concern because tropical islands are repositories of great biodiversity and are characterized by high levels of endemism and large numbers of threatened and endangered species. Furthermore, continental tropical forests that are fragmented or otherwise disturbed also are vulnerable to the impacts of exotic invaders (e.g., Humphries et al. 1992), and control of invasive exotic plants is a major cost for many land managers. Unfortunately, the options available for management of established invasive species are few and costly and carry risk of unintended consequences. A tool with great promise is the introduction of exotic hostspecific arthropods or pathogens to reduce the abundance, rate of spread, and/or habitat distribution of the target plant in its invasive range. Classical biological control is based on the premise that the population explosions of some exotic species in their introduced ranges are due in part to their escape from their native herbivoresthe ecological release hypothesis (Keane & Crawley 2002, DeWalt etal. 2004, Levine etal. 2004). Historically, the primary objective of weed biocontrol has been the direct reduction in density, cover, and range of target weeds that suppress desirable forage species, are toxic or unpalatable to livestock or that impede waterways. Most of this experience has developed in nonforest ecosystems (Coombs et al. 2004) and at temperate as opposed to tropical latitudes; among weed genera targeted by biocontrol worldwide (except Australia which has both tropical and nontropical ecosystems), 51 percent have been exclusively nontropical and only 25 percent exclusively tropical (Julien & Griffiths 1998). In some cases, this approach has met with dramatic success, e.g., St. John's wort: Hypericumperforatum L. (Harris et al. 1969), leafy spurge: Euphorbia esula L. (Harris 1993), various cactus species: Opuntia spp. (e.g., Moran & Zimmermann 1991), water hyacinth: Eichornia crassipes (Martius) Solms-Laubach (Center et al. 1999b), and giant salvinia: Salvinia molesta D. S. Mitchell (Room et al. 1981). The use of introduced arthopods and pathogens to control exotic wildland weeds is more recent but is showing promise in the control of paperbark: Melaleuca quinquenervia (Cav.) Blake in the Florida Everglades (Center et al. 2000), purple loosestrife: Lythrum salicaria L. in the northern (U.S.) wetlands (Blossey 2002), saltcedar: Tamarix spp. along western (U.S.) stream courses (DeLoach & Carruthers 2004), and several Acacia species in South Africa (Impson et al. 2000). Concern has been expressed over the use of biocontrol agents because of their potential to cause'both direct and indirect nontarget impacts (Simberloff & Stiling 1996; Louda et al. 1997, 2003; McEvoy & Coombs 2000). Nontarget impacts of introduced biocontrol agents for weeds can take the form of direct feeding by the agent on nontarget plant species (Pemberton 2000) or indirect interactions such as competition with native herbivores (Louda et al. 1997) and alteration of the community trophic structure (Henneman & Memmott 2001). Recent reviews provide evidence that the risk of direct nontarget impacts is greatest in closely related species and that the agents released following modern, widely accepted host-range testing protocols and review processes rarely affect nontarget species (Pemberton 2000). However, only a small proportion of agents released are effective at reducing the target species, and our understanding of indirect interactions of introduced biocontrol agents is rudimentary (McEvoy & Coombs 2000). As our appreciation grows of the harm caused by invasive plants in native ecosystems, the use of biological control agents in wildlands becomes increasingly attractive. Extensive use of chemical and mechanical control methods in native ecosystems also can have substantial secondary effects, including impacts on nontarget species and ecosystem processes. In addition to their high host specificity, biocontrol agents can be effective over large areas of poorly accessible terrain. In many tropical countries, where available resources-both financial and human-for the long-term control of invasive species in natural areas are small, cost-effectiveness makes biological control an attractive conservation tool. 1 Received 3 March 2005; revision accepted 17 June 2005. 2 Corresponding author; e-mail: jdenslow@fs.fed.us

The degradation of biodiversity caused by anthropic habitat destruction is a global issue. The recovery of natural habitats from invasive alien weeds in order to conserve endemic ecosystems is especially important on small oceanic islands. Planting of endemic trees may be an effective measure, but a complete restoration process within the island is essential to avoid accidental introduction of invasive aliens. To test planting techniques, we planted two endemic tree species whose regeneration was hindered by alien species on degraded lands on Chichi-jima (Ogasawara Islands) and monitored vegetation changes. During an 11-year period, about half of the Elaeocarpus photiniifolius seedlings survived in gap areas, but all Morus boninensis failed. The E. photiniifolius trees reached a height of 4.7 ± 2.4 m. The restored canopy created a dark environment that greatly reduced the volume of the predominant invasive weeds. These results suggest that E. photiniifolius is suitable for restoration of forests on degraded land and for the suppression of weeds on the island. Low species diversity in the restored forests, however, was a remaining issue to be addressed. Herein we discuss potential improvement measures to facilitate the recovery of species diversity, including other native tree candidates.

This chapter describes floristic changes, particularly in the herbaceous flora, that have occurred during recent years due to the introduction and spread of alien invasive weeds in Meghalaya and other states in north-east India. Factors favouring biological invasions are briefly covered. Some of the worst invasive weeds that have affected human health and the economic status of the tribal populations of the region are presented: Mikania micrantha, Lantana camara, Chromolaena odorata, Ageratina adenophora, Eichhornia crassipes, Galinsoga quadriradiata and Parthenium hysterophorus.

Dittrichia graveolens (L.) W. Greuter, an invasive plant species of Mediterranean origin, is recorded for the first time in Romania. We found the species in October 2020 in two separate locations along the main highway that connects Brașov and Sibiu cities, in Southern Transylvania, central Romania. We present here the first data concerning the species occurrence in the investigated area, its observed habitat, local distribution and accompanying species. We presume that the main vector for the introduction and dispersal of this species in Romania is the high traffic density along the major roads. Dittrichia graveolens has proven its invasive potential in other regions of Europe and North America of similar temperature and precipitation regimes under an overall temperate climate. Consequently, taking into account its fast dispersal, especially in the more favourable habitats for its establishment that exist along the major roads from the lower altitudes and the riparian communities from the western, southern and eastern parts of Romania, we conclude that close monitoring of the species occurrence should be undertaken in order to better assess its full invasive potential in our country and to reduce the risk of impact on natural plant communities.

The varied bioclimatic conditions of Nepal favour the introduction of different invasive alien weeds. Mikania micrantha (L.) Kunth is one of the well established invasive alien weeds in the tropical part of eastern and central Nepal. The weed has been caused serious problems in the forests, grasslands, fallow lands, croplands and wetlands of the Koshi Tappu Wildlife Reserve and its buffer zone. It kills other plants by blocking sunlight and smothering them. The Reserve has initiated to manage the weed with local community in the buffer zone. The paper attempts to highlight the problem of Mikania in the Koshi Tappu area and the efforts of community to manage the weed. Keywords: Mikania micrantha, invasive alien weed, Koshi Tappu, Nepaldoi:10.3126/on.v5i1.801Our Nature (2007)5:70-74