Fruit set and the diurnal pollinators of the invasive Lantana camara and the endemic Lantana peduncularis in the Galapagos Islands

Fruit set is highly relevant to a plant's reproductive success. Fruit set can vary due to predation on flowers, pollinator services and/or resource availability. Reproductive success, measured as the fruit set of the invasive Lantana camara and the endemic Lantana peduncularis in the cool–dry season and the warm–wet season of the Galapagos Islands, was studied. Also, autonomous self‐pollination ability and seed viability were probed for both species. Furthermore, flower visitors and their activity were registered for both species during the warm–wet season. Lantana peduncularis produced fewer flowers per inflorescence, but had a higher fruit set in the cool–dry season, compared to the warm–wet season. In contrast, the fruit set in L. camara did not change seasonally. The fruit set in L. camara was higher than in L. peduncularis in the warm–wet season. Moreover, ～18% of the bagged flowers of the invasive Lantana produced fruits by autonomous self‐pollination, while for the endemic Lantana, the rate of autonomous self‐pollination was very low. More than 80% of the fruits for both species had at least one viable seed per fruit. The number of pollinators and their frequency, inflorescence‐ and flower‐visiting rates and the duration of the visit per flower were higher in the invasive Lantana than in the endemic one. The endemic Lepidoptera Urbanus galapagensis (the main pollinator of both Lantana species) and the introduced Hymenia perspectalis were observed pollinating both Lantana species. These results indicate that the alien L. camara is more attractive to pollinators and it has reproductive advantages regarding fruit set in comparison with L. peduncularis, factors that contribute to the colonization pattern of this invasive species.     

The honeybee Apis mellifera contributes to Cucumber green mottle mosaic virus spread via pollination

The tobamovirus Cucumber green mottle mosaic virus (CGMMV) is efficiently transmitted between plants by mechanical contact. So far, no clear evidence has been reported regarding the transmission potential of the virus by beneficial pollinator insects. This study examined the capability of the well‐known pollinator honeybee Apis mellifera to transmit CGMMV in cucurbits using melon and cucumber plants as a model. In order to provide a clear answer to that question, five experiments were designed on various scales performed under three environmental conditions. The results show that under protected cropping conditions, CGMMV is transmitted by the honeybees. The location of the beehive in relation to both the CGMMV primary inoculum source and the healthy plants during honeybee foraging plays an important role in the efficiency of CGMMV spread. Furthermore, in the presence of early stage CGMMV‐inoculated plants, the efficiency of CGMMV spread to uninoculated plants placed on the honeybees’ path to the beehive may increase. To the authors’ knowledge, CGMMV transmission by honeybees has not yet been shown, and this study can be adopted for other tobamovirus related research.     

Effects of the invasive shrub,Lantana camara,on soil properties in the Eastern Cape,South Africa

Lantana camara L. is an invasive alien shrub of worldwide significance due to its impacts on biodiversity. It can alter the soil properties of invaded ecosystems and, as a result, affect management outcomes. However, knowledge on the impacts of L. camara on soil properties is scanty, especially in South Africa, despite the pervasive presence of the plant in the country. In this comparative study, the soils underneath L. camara were assessed in order to determine if they had different properties (soil physico‐chemical properties, penetration resistance, infiltration, hydraulic conductivity and water repellency) in comparison to the soils in adjacent natural sites in the Eastern Cape, South Africa. Soil samples were collected from the top soil beneath the canopy of both L. camara‐invaded and adjacent natural sites in five different locations over three summer months. The soils that were collected from underneath L. camara had a significantly higher total C, total P, gravimetric soil moisture (in November and December) and were repellent, compared to the soils in the adjacent natural sites. Soil penetration resistance was significantly higher in the natural sites than in the L. camara‐invaded sites. The soil hydraulic conductivity, soil infiltration rate, soil pH, exchangeable cations and total N showed no significant difference between the invaded and the natural sites. It appears that the soils underneath L. camara have a high total C and total P, soil moisture and are repellent, thus influencing nutrient cycling, potentially making the soil properties underneath it ideal for its own growth. This could contribute to the success of L. camara as an invasive species.     

Reproduction of Hedysarum scoparium (Fabaceae) in patched habitat is pollen limited, but not just pollinator limited

Pollen limitation of plant reproduction occurs across Angiosperms,particularly those in patched habitats.We investigated the relationship between pollen limitation and patch variables (patch size,visitation frequency) in the desert plant Hedysarum scoparium (Fabaceae),which is an important xerophyte in the arid and semi-arid regions of Northwest China and can grow well as a pioneer plant in shifting sand dunes.We observed insect visitation to H.scoparium over two flowering seasons and estimated pollen limitation using fruit set and seed production.Our results indicate that fruit set and seed production increased significantly with pollen supplementation compared with open pollination.Hedysarum scoparium was pollinated by over 8 species of bees,with 88.4% of visits made by introduced honeybees (Apis mellifera).Bee visitation varied significantly among the patches of habitats,but not associated with patch size of habitat.In general,pollen limitation occurred more strongly during fruit set than during seed production.The patches that received higher rates of pollinator visits were less pollen limited for fruit set.Pollen limitation for seed production,however,was not associated with pollinator visitation frequency.We conclude that pollen limitation in H.scoparium was caused by more than one reason,not just pollinator visits.     

Flowering behaviors of the inflorescences of an alien plant (Plantago asiatica), an alpine plant (Plantago hakusanensis), and their hybrids on Mt. Hakusan,Japan

In the subalpine zone on Mt. Hakusan, Japan, Plantago asiatica, an alien plant, and Plantago hakusanensis, a native alpine species, grow sympatrically along with their putative hybrids. Here, their flowering behavior, which affects the frequency of hybridization and the colonizing ability of P. asiatica and its hybrids, is described. The flowering behavior of each species and of two F₁ hybrids from different seed parents was determined based on the position of the flower in the inflorescence by using a generalized linear mixed model. The percentage fruit set of individually bagged inflorescences was calculated to corroborate the assumptions of the opportunities for self‐pollination. All the flowers were protogynous; however, many P. asiatica anthers dehisced before browning of the stigma in the flower and the sex presentations in the inflorescence were asynchronous. The percentage of fruit set was high. Consequently, P. asiatica has the opportunity for self‐pollination within the flower and in the inflorescence. In contrast, the P. hakusanensis anthers dehisced after browning of the stigma in the flower; their sex presentation was synchronous in the inflorescence, showing negligible opportunities for self‐pollination, and the fruit set was low. Accordingly, in the field, P. hakusanensis might require pollination among the inflorescences for seed production and be actively outcrossed, while P. asiatica is able to outcross in the early flowering phase. Therefore, P. asiatica and P. hakusanensis have opportunities for hybridization. The F₁ hybrids exhibited intermediate flowering behavior and produced fruits, demonstrating the potential to reproduce by selfing.     

Herbicidal potential of allelochemicals from Lantana camara against Eichhornia crassipes and the alga Microcystis aeruginosa

In the field, the growth of the aquatic weed Eichhornia crassipes and the alga Microcystis aeruginosa may be inhibited by fallen leaves of Lantana camara. This study showed that extracts of L. camara leaves and their fractions reduced the biomass of E. crassipes and M. aeruginosa within 7 days under laboratory conditions. Two fractions with highly inhibitory activity from the extract were isolated and subsequently identified as the pentacyclic triterpenoids, lantadene A and lantadene B. Both compounds significantly inhibited E. crassipes and M. aeruginosa growth, even at a low concentration. At all concentrations tested, their inhibitory activities were much higher than that of salicylic acid, a putative allelochemical from L. camara. The results indicated that the predominant allelochemicals involved in L. camara against either E. crassipes or M. aeruginosa are not phenolic acids, but lantadene A and lantadene B. Field trials showed that released levels of lantadene A and lantadene B were significantly correlated with amounts and decomposition periods of L. camara leaves floated in water. The amount released from 5 kg L. camara leaves was over the inhibition threshold of both E. crassipes and M. aeruginosa and reached a maximum at days 15–20. This study suggested that allelochemicals of L. camara could potentially be used to improve the management of weeds and algae in aquatic systems.     

Extended longevity of Erwinia amylovora vectored by honeybees under in vitro conditions and its capacity for dissemination

Fire blight outbreaks in Korea were first reported in 2015. Regular outbreaks have occurred since, indicating a continuous cycle of the fire blight pathogen in Korea. We determined the role of Apis mellifera (honeybee) as a vector of Erwinia amylovora by verifying the following: (a) E. amylovora longevity in/on honeybees; (b) the most common body parts that carry the bacteria; (c) the rate of bacterial spread to healthy host organs; and (d) the relationship between dispersal of viable but nonculturable (VBNC) and virulent bacterial cells. E. amylovora survived for 15 days on the exterior of honeybee bodies and was most abundant on the abdomen in comparison to other areas such as the labellum, wings, and hind legs. In the digestive system of honeybees, E. amylovora survived for 7 days, and bacteria were found in faeces for 3 days after exposure. The bacteria are likely to be VBNC on honeybees. Honeybees that were contaminated with bacteria transferred E. amylovora to healthy immature apple fruit, shoots, and flowers for 10 days after exposure. E. amylovora was also transferred from inoculated plant parts to uncontaminated honeybees. In addition, bacteria moved from inoculated plant tissues to unexposed honeybees and then from these honeybees to healthy plant tissues. Therefore, E. amylovora can survive in/on honeybees for extended amounts of time, which contradicts previous reports. The bacteria moved to host tissues via honeybees, suggesting that honeybees are the vectors of E. amylovora and play a role in the development of new outbreaks of fire blight disease in the central regions of Korea.     

Honeybees can spread Colletotrichum acutatum and C. gloeosporioides among citrus plants

Postbloom fruit drop (PFD) is an important citrus disease that causes up to 100% yield losses during years in which conditions are favourable for the occurrence of epidemics. The conidia of Colletotrichum acutatum and C. gloeosporioides, causal agents of PFD, are predominantly dispersed by rain splash. At the beginning of epidemics, the distribution of diseased plants is random and the disease progress rate is very high, which is unusual for pathogens spread by rain splash. As the pathogen produces abundant conidia on diseased petals, pollinating insects may contribute to disease dispersal. This study investigated honeybees (Apis mellifera) as dispersal agents of C. acutatum and C. gloeosporioides among citrus plants. Two experiments were carried out in a screenhouse in which citrus plants were protected (or not) in insect‐proof cages. The source of inoculum was placed on one side of the screenhouse, and a honeybee hive was placed on the opposite side. All uncaged plants showed symptoms of the disease, and none of the caged plants exhibited PFD symptoms. The monomolecular model showed a good fit to disease progress in both experiments. Conidium‐like structures of Colletotrichum spp. were identified attached to the bodies of the honeybees by scanning electron microscopy. These results have revealed that honeybees disperse Colletotrichum among citrus plants.     

Invasive African boneseed and a native shrub support similar faunal assemblages in a heavily infested landscape

Invasive weeds may provide habitat for wildlife in altered landscapes. We compare fauna within three types of sites in You Yangs Regional Park in central Victoria, Australia, that is, sites with an invasive shrub understory (African boneseed, Chrysanthemoides monilifera subsp. monilifera (DC.) T. Norl.), native shrub understory (snowy mintbush Prostanthera nivea), and sites without an understory (open sites). Sites with an understory dominated by boneseed provided habitat for avian species and an introduced small mammal, comparable with sites with mintbush as the understory. Species-specific models of common species suggest vegetation structure, rather than composition, drove this effect. Open sites differed in terms of avifaunal assemblage, and the abundance of three common native birds and one common invasive small mammal. Boneseed additionally showed phenological differences in fruiting and flowering and differences in flowering abundance when compared with mintbush, comparably offering resources to wildlife. Transitioning vegetation communities to more natural states should consider wildlife already depending on weeds, a dependency likely driven by a paucity of alternative native vegetation.     

Germinable soil seedbanks of central Queensland rangelands invaded by the exotic weed Parthenium hysterophorus L.

The germinable soil seedbank was determined at two sites in central Queensland on four separate occasions between February 1995 and October 1996. These sites were infested with parthenium weed ( Parthenium hysterophorus L.), a serious invasive exotic weed. During this period, the seedbank varied between 3282 and 5094 seeds m⁻² at the Clermont site, and between 20 599 and 44 639 seeds m⁻² at the Moolayember Creek site. Parthenium hysterophorus exhibited a very abundant and persistent seedbank, accounting for 47–73% of the seedbank at Clermont and 65–87% of the seedbank at Moolayember Creek. The species richness and species diversity of the seedbank, and the seed abundance of many species, was lower at Moolayember Creek during spring (the time of year when the most dense infestations of the weed originate). Parthenium hysterophorus seedlings also emerged more rapidly from the soil samples than did those of all other species. Hence, it seems that various aspects of the weed's seed ecology, including abundance and the persistence of its seedbank and the rapid emergence of its seedlings, are major factors contributing to its aggressiveness in semiarid rangeland communities in central Queensland. The domination by P . hysterophorus of the seedbanks of these sites suggests that the weed is having a substantial negative impact on the ecology of these plant communities. The diversity of these seedbanks was found to be lower in comparison with that observed in other grassland communities that were not dominated by an invasive weed species. Hence, the prolonged presence of P . hysterophorus may have substantially reduced the diversity of these seedbanks, thereby reducing the ability of some of the native species to regenerate in the future.     

Competition of sorghum cultivars and densities with Japanese millet (Echinochloa esculenta)

Field studies were conducted at two locations in southern Queensland, Australia during the 2003–2004 and 2004–2005 growing seasons to determine the differential competitiveness of sorghum (Sorghum bicolor L. Moench) cultivars and crop densities against weeds and the sorghum yield loss due to weeds. Weed competition was investigated by growing sorghum in the presence or absence of a model grass weed, Japanese millet (Echinochloa esculenta). The correlation analyses showed that the early growth traits (height, shoot biomass, and daily growth rate of the shoot biomass) of sorghum adversely affected the height, biomass, and seed production of millet, as measured at maturity. “MR Goldrush” and “Bonus MR” were the most competitive cultivars, resulting in reduced weed biomass, weed density, and weed seed production. The density of sorghum also had a significant effect on the crop's ability to compete with millet. When compared to the density of 4.5 plants per m², sorghum that was planted at 7.5 plants per m² suppressed the density, biomass, and seed production of millet by 22%, 27% and 38%, respectively. Millet caused a significant yield loss in comparison with the weed‐free plots. The combined weed‐suppressive effects of the competitive cultivars, such as MR Goldrush, and high crop densities minimized the yield losses from the weeds. These results indicate that sorghum competition against grass weeds can be improved by choosing competitive cultivars and by using a high crop density of >7.5 plants per m². These non‐chemical options should be included in an integrated weed management program for better weed management, particularly where the control options are limited by the evolution of herbicide resistance.     

Ecological pest management and control by using allelopathic weeds (Ageratum conyzoides,Ambrosia trifida,and Lantana camara) and their allelochemicals in China

The development of pest management and control is striving toward a future of sustainable agriculture. Weeds cause serious problems in agricultural ecosystems and attempts to control them have met with limited success. However, many weeds are allelopathic; that is, they can produce and release allelochemicals to interact with other plant competitors and to attack microbes or insect and other animal predators. These allelopathic weeds and their allelochemicals may be put into use for ecological pest management and control or employed for other uses. Currently, little attention has been paid to how allelopathic weeds and their allelochemicals potentially can be utilized as an important part of pest management and control in agricultural ecosystems. This review outlines recent research regarding the potential for pest management and control by allelopathic weeds and their allelochemicals by studying the cases of Ageratum conyzoides, Ambrosia trifida, and Lantana camara and provides examples of allelopathic weeds and their allelochemicals that have been incorporated into ecological pest management and control in China.     

Are honeybees suitable surrogates for use in pesticide risk assessment for non‐Apis bees?

Historically, bee regulatory risk assessment for pesticides has centred on the European honeybee (Apis mellifera), primarily due to its availability and adaptability to laboratory conditions. Recently, there have been efforts to develop a battery of laboratory toxicity tests for a range of non‐Apis bee species to directly assess the risk to them. However, it is not clear whether the substantial investment associated with the development and implementation of such routine screening will actually improve the level of protection of non‐Apis bees. We argue, using published acute toxicity data from a range of bee species and standard regulatory exposure scenarios, that current first‐tier honeybee acute risk assessment schemes utilised by regulatory authorities are protective of other bee species and further tests should be conducted only in cases of concern. We propose similar analysis of alternative exposure scenarios (chronic and developmental) once reliable data for non‐Apis bees are available to expand our approach to these scenarios. In addition, we propose that in silico (simulation) approaches can then be used to address population‐level effects in more field‐realistic scenarios. Such an approach could lead to a protective, but also workable, risk assessment for non‐Apis species while contributing to pollination security in agricultural landscapes around the globe. © 2019 Society of Chemical Industry     

Multiple Alternaria species groups are associated with leaf blotch and fruit spot diseases of apple in Australia

Leaf blotch and fruit spot of apple caused by Alternaria species occur in apple orchards in Australia. However, there is no information on the identity of the pathogens and whether one or more Alternaria species cause both diseases in Australia. Using DNA sequencing and morphological and cultural characteristics of 51 isolates obtained from apple leaves and fruit with symptoms in Australia, Alternaria species groups associated with leaf blotch and fruit spot of apples were identified. Sequences of Alternaria allergen a1 and endopolygalacturonase gene regions revealed that multiple Alternaria species groups are associated with both diseases. Phylogenetic analysis of concatenated sequences of the two genes resulted in four clades representing A. arborescens and A. arborescens‐like isolates in clade 1, A. tenuissima/A. mali isolates in clade 2, A. alternata/A. tenuissima intermediate isolates in clade 3 and A. longipes and A. longipes‐like isolates in clade 4. The clades formed using sequence information were supported by colony characteristics and sporulation patterns. The source of the isolates in each clade included both the leaf blotch variant and the fruit spot variant of the disease. Alternaria arborescens‐like isolates were the most prevalent (47%) and occurred in all six states of Australia, while A. alternata/A. tenuissima intermediate isolates (14%) and A. tenuissima/A. mali isolates (6%) occurred mostly in Queensland and New South Wales, respectively. Implications of multiple Alternaria species groups on apples in Australia are discussed.     

Influence of weedy field margins on abundance patterns of the predatory bugs <Emphasis Type="BoldItalic">Orius</Emphasis> spp. and their prey,the western flower thrips (<Emphasis Type="BoldItalic">Frankliniella occidentalis</Emphasis>), on faba bean

The influence of weedy field strips on the abundance patterns of western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), and predatory bugs of Orius spp. (Hemiptera: Anthocoridae), on faba bean and on weeds was investigated in Adana province, Turkey, during 2005–2006. There were two treatments: in one treatment, weeds at the margins and inside the plots were regularly controlled by tillage; in the other treatment no weed control was done. Thrips and Orius were sampled by beating faba bean plants and weeds. Orius niger (Wolff) was the most abundant predatory insect species in faba bean and flowering weeds, with numbers of adults and nymphs significantly greater in plots with weedy margins than in weed-free plots. Flowering weeds did not contribute to the abundance of F. occidentalis on faba bean. Abundance of adults of Orius spp. did not coincide with the abundance of F. occidentalis on faba bean or weeds. There were significant negative associations for numbers of Orius spp. among faba bean and the weed species Lamium amplexicaule L. or Sinapis arvensis L. (P < 0.05), indicating movement of Orius individuals from the weeds to faba bean during March–April. Finally, faba bean and weeds may provide some benefits to predators, such as nectar, pollen, shelter and egg-laying sites rather than as sources of insect prey. Cultivation of faba bean could be useful for conservation and augmentation of beneficial insects, including Orius spp. Furthermore, field margins bearing flowering weeds such as S. arvensis and L amplexicaule should be protected against destructive management practices, because they host considerable numbers of the Orius species.     

Chemical control of Crotalaria goreensis and other weeds in Macroptilium atropurpureum

The effects of several selective herbicides, combinations of diuron with activated carbon, slashing and stale seed bed treatments were tested in five field experiments conducted at Walkamin, Queensland, Australia to determine the best methods of controlling weeds, particularly the legume Crotalaria goreensis Guill. & Perr., in crops of Macroptilium atropurpureum (DC.) Urb. cv. Siratro, grown for seed. Alachlor alone and combinations of trifluralin with either alachlor or propachlor were effective in preventing weeds causing a yield reduction in one experiment but not in a second. Trifluralin plus propachlor was more effective in controlling broad-leaved weeds while trifluralin plus alachlor was more effective in controlling grasses. Activated carbon effectively protected M. atropurpureum from diuron damage but the control of weeds, particularly grasses, was not effective. Stale seed bed treatments involving three sequential applications of diquat prior to planting the crop was the most effective method of controlling C. goreensis.     

From weed biology to successful control: an example of successful management of Ludwigia grandiflora in Germany

Ludwigia grandiflora (water primrose), a native to the Americas, is one of the most important invasive alien aquatic plants in Europe. In Germany, a first population was found in an oxbow lake of the River Leda in Lower Saxony, north‐western Germany, in 2004. Ludwigia grandiflora formed both dense monospecific patches and mixed stands with native plants. A study on the biology of L. grandiflora documented that the plants regrow in spring from vegetative means only, even though viable seed production occurred. Hand weeding was successfully tested in different sampling sites as a sustainable management tool and subsequently used for the management of this species. Within 3 days, more than 99% of the biomass (25 tonnes of fresh mass) was harvested in 2013. Afterwards, a one‐day post‐treatment in the same year, two‐one‐day treatments in 2014 and one‐one‐day treatment in 2015 were made to harvest the regrown plants. After the first year, plant regrowth occurred only in one extremely muddy site, while in more than 99% of the water body, L. grandiflora was eradicated. Even though L. grandiflora was not completely eradicated from the water, a total eradication seems achievable within the next few years. The study documented the difficulties in the management of aquatic weeds, particularly in heterogeneous habitats with varying sediment structure. Management measures must be adapted to the infested habitat and species biology, which is mandatory for successful management of all aquatic weeds.     

Herbicide‐resistant genetically‐modified crop: its risks with an emphasis on gene flow

Herbicide‐resistant genetically‐modified (GM) crops are the most widely cultivated worldwide, representing 78% of GM crops in 1999, followed by insect‐resistant GM crops with Bt gene. Gene flow is the most touching risk arising from GM crops, and is categorized as three types: within species, between species and between GM crop and other organisms. This review shows that gene flow is a reality in the plant kingdom with evolutionary change. Herbicide resistance evolves naturally and spreads dynamically in weeds. One of the most concerning crop in relation to gene flow is Brassica napus, which has a high outcrossing rate and many relative species. In contrast, frequency of gene flow via outcrossing is relatively low in inbreeding cereal crops such as rice, wheat and barley, but published reports have shown that substantial gene flow is possible. Another possible and immediate risk is herbicide‐resistant GM crops becoming volunteer weeds. Dry direct‐seeded rice is one of the most likely crops in this respect. Stacking different resistance genes in a crop would accelerate multiple resistance evolution in weeds. Multiple resistance to three major herbicides has already been observed in oilseed rape cultivation. More efforts must be made for long‐term risk assessment on GM crops in the natural ecosystem. More studies on weed biology and ecology, particularly reproductive processes in weeds, are essential for better understanding of gene flow and systematic management strategy. We hope that this review motivates researchers to analyze data available now, to collect fundamental information on crops and weeds in agro‐ecosystem, and to lead to better risk assessment and management.     

Pollination of chasmogamous flowers and the effects of light and emergence time on chasmogamy and cleistogamy in Monochoria vaginalis

Monochoria vaginalis is one of the most serious weeds of rice fields in Asia. The species has both chasmogamous (CH) and cleistogamous (CL) flowers on individual plants. The objective of this study is to clarify the reproductive characteristics that affect the selfing rate of M. vaginalis. An emasculation experiment revealed that the CH flowers emasculated just after flower opening produced seeds. The seed production in the flowers emasculated just after flower opening was less than that of the flowers emasculated and hand‐pollinated with pollen from another plant. These results indicate that, although self‐pollination before anthesis occurs, cross‐pollination also can produce seeds. An experimental manipulation of light and the emergence time of the plants revealed that more than half of the flowers produced were CL flowers and the CH/CL ratio decreased with reduced light availability. The plants that emerged later produced as many CH flowers as those that emerged earlier. There was no significant difference between the CH and CL flowers in the seed number per fruit and the seed mass. These results suggest that M. vaginalis has reproductive characteristics that make the selfing rate high; however, outcrossing also can occur. Under favorable light intensity conditions, such as on the edges of paddy fields or in fallow fields, M. vaginalis will produce more CH flowers and will have a higher outcrossing rate than in shaded conditions.     

Teratosphaeria pseudoeucalypti,new cryptic species responsible for leaf blight of Eucalyptus in subtropical and tropical Australia

Sub‐tropical and tropical plantations of Eucalyptus grandis hybrids in eastern Australia have been severely affected by anamorphs of Teratosphaeria (formerly Kirramyces) causing a serious leaf blight disease. Initially the causal organism in Queensland, Australia, was identified as Teratosphaeria eucalypti, a known leaf parasite of endemic Eucalyptus spp. However, some inconsistencies in symptoms, damage and host range suggested that the pathogen in Queensland may be a new species. Isolates of T. eucalypti from throughout its known endemic range, including Queensland and New Zealand, where it is an exotic pathogen, were compared using multiple gene phylogenies. Phylogenetic studies revealed that the species responsible for leaf blight in Queensland represents a new taxon, described here as Teratosphaeria pseudoeucalypti. While the DNA sequence of T. pseudoeucalypti was more similar to T. eucalypti, the symptoms and cultural characteristics resembled that of T. destructans. The impact of this disease in central Queensland has increased annually and is the major threat to the eucalypt plantation industry in the region.