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Understanding how the biological invasion is driven by environmental factors will improve model prediction and advance early detection, especially in the context of accelerating anthropogenic ecological changes. Although a large body of studies has examined how favorable environments promote biological invasions, a more comprehensive and mechanistic understanding of invasive species response to unfavorable/stressful conditions is still developing. Grass invasion has been problematic across the globe; in particular, C 4 grass invaders, with high drought tolerance, adaptations to high temperatures, and high water use efficiency, could become more severe. Here, we conducted a rigorous microcosm experiment, with one of the most damaging invasive C 4 grass, cogongrass (Imperata cylindrica), to explore how cogongrass responds to soil water and nutrient stress. We further integrated the results of the microcosm study with a species distribution model to (1) corroborate greenhouse results with field observations and (2) validate the robustness of our findings at subcontinental scales. Both the microcosm experiments and species distribution model agreed that soil water stress had a stronger impact on cogongrass than the nutrient one. New vegetative growth of cogongrass continued to be inhibited by the prior water stress. The significant water effect on cogongrass total biomass was supported by the finding that both allometric and biochemical traits of cogongrass did not show significant responses to the changes in water treatment. Different to the conventional wisdom that nutrient enrichment plays a bigger role in facilitating biological invasions, this study highlighted the possibility that water conditions may have a more substantial effect on some aggressive invaders. Therefore, an important implication of this study on biological conservation is that field managers might take advantage of the negative effect of global drought on some invasive species to increase the efficiency of their controlling efforts because invasive species may become more vulnerable under drought effect., (© 2021 by the Ecological Society of America.)

Mosquito larvicides are an effective tool for reducing numbers of adult females that bite and potentially spread pathogenic organisms. Methionine, an essential amino acid in humans, has been previously demonstrated to be a highly effective larvicide against four (4) mosquito species in three (3) genera, Anopheles, Culex and Aedes. The aim of the present study was to determine the potential impact on non-target aquatic organisms of methionine applied as a mosquito larvicide. DL-methionine concentrations ranging from 0.06% to 1.00% were used; wherein the highest concentration of 1.00% would result in 100% mortality within 48 h in mosquitoes. Acute toxicity assays were conducted in accordance with the US Environmental Protection Agency (US EPA) guidelines for the water flea (Daphnia magna Straus; Cladocera: Daphniidae) and the fathead minnow (Pimephales promelas Rafinesque; Cypriniformes: Cyprinidae). Water fleas and fish were placed directly into the solutions in glass containers and tanks for 48-hours and 96-hours, respectively. When applied within the above-mentioned range of effective mosquito larvicide concentrations, DL-methionine meets US EPA criteria as a "practically non-toxic" pesticide for both species. These results suggest that methionine is a viable alternative to current mosquito larvicide options, which are typically classified as moderately to highly toxic and may be a valuable addition to a mosquito integrated pest management program., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)

Mosquito larvicides can reduce mosquito populations at the source, potentially decreasing biting rates and pathogen transmission. However, there is a growing need for mosquito larvicides that are environmentally sustainable. Bacillus thuringiensis subspecies israelensis (BTI) is a naturally occurring bacterium commonly used as a larvicide to manage mosquito populations. Methionine is an essential amino acid that has demonstrated toxic properties against larval mosquitoes in laboratory experiments, while having minimal effects on non-target organisms. The goal of this study was to evaluate the potential for a novel combination larvicide by testing for compatibility between these two active ingredients. We began by determining the lethal concentration values (LCs) of BTI and DL-methionine against Anopheles quadrimaculatus Say and Aedes aegypti Linnaeus (Diptera: Culicidae) larvae. These bioassays were conducted in glass jars and mortality was observed 48 h post-treatment. We found that while DL-methionine was more toxic to An. quadrimaculatus than Ae. aegypti , the opposite was true for BTI. Then, we used these LCs to conduct bioassays with a combination of BTI and DL-methionine to determine the relationship between the two active ingredients when used against An. quadrimaculatus and Ae. aegypti larvae. The findings of this study demonstrate that BTI and DL-methionine have the potential to be complementary due to their additive properties at higher concentrations and effect levels when tested against An. quadrimaculatus . However, an antagonistic relationship was detected at the concentrations tested with Ae. aegypti. These results are encouraging and imply that a DL-methionine or BTI/DL-methionine combination larvicide could be used in management of Anopheles species.

Background: Mosquito larvicides provide a source-reduction strategy to diminish adult females that bite and potentially spread pathogens. Demands are mounting for new and innovative effective biorational larvicides, due to the development of resistance to some currently utilized mosquito larvicides, undesirable non-target effects, and US Environmental Protection Agency (EPA) restrictions. Methionine is a human nutrient essential amino acid that unexpectedly has been shown to be a valuable safe pest management tool against select insect pests that possess alkaline gut physiology. The present study evaluated larvicidal toxicity of methionine in several pestiferous mosquito (Diptera: Culicidae) genera., Results: Concentration-dependent DL-methionine kinetics assays of survival and pupation were conducted in larvae of Aedes albopictus Skuse, Anopheles quadrimaculatus Say, and Culex tarsalis Coquillett in glass jars. High concentrations of DL-methionine yielded 100% mortality for all test species and prevented pupation at a rate equivalent to Bacillus thuringiensis israelensis (Bti) treatments. Concentration kinetics indicated that An. quadrimaculatus was 10-fold more sensitive to DL-methionine than Ae. albopictus and Cx. tarsalis., Conclusions: EPA regulations currently exempt methionine in pesticide formulations applied to agricultural crops. This study demonstrates that methionine is a highly effective mosquito larvicide that can provide a beneficial new biorational, environmentally sustainable tool to control pestiferous mosquitoes. © 2018 Society of Chemical Industry., (© 2018 Society of Chemical Industry.)

Methionine is an essential/indispensible amino acid nutrient required by adult and larval honey bees (Apis mellifera L. [Hymenoptera: Apidae]). Bees are unable to rear broods on pollen deficient in methionine, and reportedly behaviorally avoid collecting pollen or nectar from florets deficient in methioinine. In contrast, it has been demonstrated that methionine is toxic to certain pest insects; thus it has been proposed as an effective biopesticide. As an ecofriendly integrated pest management agent, methionine boasts a novel mode of action differentiating it from conventional pesticides, while providing non-target safety. Pesticides that minimize collateral effects on bees are desirable, given the economic and ecological concerns about honey bee health. The aim of the present study was to assess the potential impact of the biopesticide methionine on non-target adult and larval honey bees. Acute contact adult toxicology bioassays, oral adult assessments and chronic larval toxicity assessments were performed as per U.S. Environmental Protection Agency (EPA) requirements. Our results demonstrated that methionine fits the U.S. EPA category of practically nontoxic (i.e. lethal dose to 50% mortality or LD 50 > 11µg/bee) to adult honey bees. The contact LD 50 was > 25µg/bee and the oral LD 50 was > 100µg/bee. Mortality was observed in larval bees that ingested DL-methionine (effective concentration to 50% mortality or EC 50 560µg/bee). Therefore, we conclude that methionine poses little threat to the health of the honey bee, due to unlikely exposure at concentrations shown to elicit toxic effects., (Copyright © 2017 Elsevier Inc. All rights reserved.)

A chironomid midge, Cricotopus lebetis (Sublette) (Diptera: Chironomidae), was discovered attacking the apical meristems of Hydrilla verticillata (L.f. Royle) in Crystal River, Citrus Co., Florida in 1992. The larvae mine the stems of H. verticillata and cause basal branching and stunting of the plant. Temperature-dependent development, cold tolerance, and the potential distribution of the midge were investigated. The results of the temperature-dependent development study showed that optimal temperatures for larval development were between 20 and 30°C, and these data were used to construct a map of the potential number of generations per year of C. lebetis in Florida. Data from the cold tolerance study, in conjunction with historical weather data, were used to generate a predicted distribution of C. lebetis in the United States. A distribution was also predicted using an ecological niche modeling approach by characterizing the climate at locations where C. lebetis is known to occur and then finding other locations with similar climate. The distributions predicted using the two modeling approaches were not significantly different and suggested that much of the southeastern United States was climatically suitable for C. lebetis., (© The Author 2014. Published by Oxford University Press on behalf of the Entomological Society of America.)

Fipronil, a relatively new insecticide more recently developed than organophosphates and pyrethroids, has been detected in surface water draining from agricultural and urban-developed areas. This insecticide is primarily lost through subsurface and surface drainage from terrestrial areas where it has been applied. Invasive aquatic plants often need to be managed in these receiving water bodies to prevent loss of recreational and functional values (e.g., drainage), especially in subtropical and tropical areas. One insect of particular interest is the chironomid midge Cricotopus lebetis Sublette, which may be a useful augmentative biocontrol agent for the invasive aquatic weed Hydrilla verticillata L.f. Royale. Exposure of aquatic organisms, especially insects, to fipronil may significantly impact nontarget populations. These studies investigated the sensitivity of C. lebetis to fipronil exposures ranging from 24 to 96 h. The LC50 observed for each exposure interval was 7.26 μg/L (24 h), 2.61 μg/L (48 h), 1.78 μg/L (72 h), and 1.06 μg/L (96 h). The LC90 values observed were 47.18 μg/L (24 h), 9.55 μg/L (48 h), 6.45 μg/L (72 h), and 4.81 μg/L (96 h). Behavioral changes were seen at all fipronil concentration levels, where larvae exited the plant and exhibited abnormal behavior, such as restricted movement and lack of feeding. Results indicate that acute lethality occurred at environmentally relevant concentrations of fipronil.

ABSTRACT The Southeast Asian citrus-feeding butterfly Princeps (Papilio) demoleus (L.) was recently introduced into the Americas, causing an imminent threat to citrus production and ornamental flora. The human nutrient amino acid methionine has been shown by us to disrupt aminoacid-modulated ion transport systems in caterpillars and other insect larvae that possess an alkaline midgut. Heraclides (Papilio) cresphontes was bioassayed as a United States Department of Agriculture permitted surrogate of the Florida quarantined P. demoleus to test the potential efficacy of methionine. Larvae were allowed to feed ad libitum on wild lime plants with leaves treated with methionine or proline. Methionine caused 100% mortality in first through fourth instars in a time- and dose-dependent manner, as determined by probit analysis whereas proline was not toxic. Wild lime host plants did not exhibit phytotoxicity with methionine treatments during a 14 d test period. It is concluded that methionine is an effective larvicide against H. cresphontes, and therefore may be a candidate environmentally safe biorational pesticide for use against invasive P. demoleus in the Americas.

Schinus terebinthifolius Raddi (Sapindales: Anacardiaceae) is a non-native perennial woody plant that is one of the most invasive weeds in Florida, Hawaii, and more recently California and Texas. This plant was introduced into Florida from South America as a landscape ornamental in the late 19th century, eventually escaped cultivation, and now dominates entire ecosystems in south-central Florida. Recent DNA studies have confirmed two separate introductions of S. terebinthifolius in Florida, and there is evidence of hybridization. A thrips, Pseudophilothrips ichini s.l. (Hood) (Thysanoptera: Phlaeothripidae), is commonly found attacking shoots and flowers of S. terebinthifolius in Brazil. Immatures and occasionally adults form large aggregations on young terminal growth (stems and leaves) of the plant. Feeding damage by P. ichini s.l. frequently kills new shoots, which reduces vigor and restricts growth of S. terebinthifolius. Greenhouse and laboratory host range tests with 46 plant species in 18 families and 10 orders were conducted in Paraná, Brazil, and Florida. Results of no-choice, paired-choice, and multiple-choice tests indicated that P. ichini s.l. is capable of reproducing only on S. terebinthifolius and possibly Schinus molle L., an ornamental introduced into California from Peru that has escaped cultivation and is considered invasive. Our results showed that P. ichini s.l. posed minimal risk to mature S. molle plants or the Florida native Metopium toxiferum L. Krug and Urb. In May 2007, the federal interagency Technical Advisory Group for Biological Control Agents of Weeds (TAG) concluded P. ichini s.l. was sufficiently host specific to recommend its release from quarantine.

This article documents the addition of 512 microsatellite marker loci and nine pairs of Single Nucleotide Polymorphism (SNP) sequencing primers to the Molecular Ecology Resources Database. Loci were developed for the following species: Alcippe morrisonia morrisonia, Bashania fangiana, Bashania fargesii, Chaetodon vagabundus, Colletes floralis, Coluber constrictor flaviventris, Coptotermes gestroi, Crotophaga major, Cyprinella lutrensis, Danaus plexippus, Fagus grandifolia, Falco tinnunculus, Fletcherimyia fletcheri, Hydrilla verticillata, Laterallus jamaicensis coturniculus, Leavenworthia alabamica, Marmosops incanus, Miichthys miiuy, Nasua nasua, Noturus exilis, Odontesthes bonariensis, Quadrula fragosa, Pinctada maxima, Pseudaletia separata, Pseudoperonospora cubensis, Podocarpus elatus, Portunus trituberculatus, Rhagoletis cerasi, Rhinella schneideri, Sarracenia alata, Skeletonema marinoi, Sminthurus viridis, Syngnathus abaster, Uroteuthis (Photololigo) chinensis, Verticillium dahliae, Wasmannia auropunctata, and Zygochlamys patagonica. These loci were cross-tested on the following species: Chaetodon baronessa, Falco columbarius, Falco eleonorae, Falco naumanni, Falco peregrinus, Falco subbuteo, Didelphis aurita, Gracilinanus microtarsus, Marmosops paulensis, Monodelphis Americana, Odontesthes hatcheri, Podocarpus grayi, Podocarpus lawrencei, Podocarpus smithii, Portunus pelagicus, Syngnathus acus, Syngnathus typhle,Uroteuthis (Photololigo) edulis, Uroteuthis (Photololigo) duvauceli and Verticillium albo-atrum. This article also documents the addition of nine sequencing primer pairs and sixteen allele specific primers or probes for Oncorhynchus mykiss and Oncorhynchus tshawytscha; these primers and assays were cross-tested in both species., (© 2009 Blackwell Publishing Ltd.)

Plant-parasitic nematodes are important pathogens of intensely-managed turf used on golf courses. Two of these nematodes that are common in the southeastern US are Belonolaimus longicaudatus and Mesocriconema ornata. Currently, there is a lack of effective treatments that can be used to manage these important pests. Turfgrass field trials evaluated DL-methionine as a turfgrass nematicide against B. longicaudatus and M. ornata. One trial was on a bermudagrass putting green, the other was on zoysiagrass maintained under putting-green conditions. Two rates of methionine, 1120 kg/ha in a single application, and 112 kg/ha applied twice four weeks apart, were compared with untreated control and fenamiphos treatments. Measurements collected included soil nematode counts, turf density, and root lengths. In both trials, 1120 kg/ha of methionine reduced numbers of both nematode species (P ≤ 0.1), and 112 kg/ha of methionine reduced numbers of both nematode species after two applications. Bermudagrass turf density responded favorably to both methionine rates and root lengths were improved by the 1120 kg/ha rate. Zoysiagrass showed short-term phytotoxicity to methionine, but quickly recovered and treated plots were improved compared to the untreated controls by the end of the trial. These trials indicated that methionine has potential for development as a turfgrass nematicide, but further research is needed to determine how it can best be used.

The invasive Brazilian peppertree (Schinus terebinthifolius Raddi), native to South America, is widely established throughout central and south Florida. The defoliating leaflet-roller Episimus utilis Zimmerman was selected as potential biocontrol agent of this invasive species. The objectives of this study were to determine development rate and survival of E. utilis at seven constant temperatures (10, 15, 20, 25, 30, 33, and 35 degrees C) and generate prediction maps of the number of generations per year this species may exhibit in the United States. The rate of development of E. utilis as a function of temperature was modeled using linear regression to estimate a lower developmental threshold of 9.6 degrees C and the degree-day requirement of 588. The Logan nonlinear regression model was used to estimate an upper developmental threshold of 33 degrees C. Cold tolerance of E. utilis was examined using all insect stages, and each stage was exposed to three constant temperatures (10, 5, 0 degrees C) for 0.5, 1, 2, 4, and 8 d (or until all insects died). The pupal stage was the most cold tolerant with 100% mortality after 12 d at 0 degrees C. The pupal lethal times at 5 (Ltime50 = 10 d, Ltime90 = 28 d) and 0 degrees C (Ltime50 = 5 d, Ltime90 = 9 d) were used to generate isothermal lines to predict favorable regions for E. utilis establishment. A GIS map was generated to predict the number of generations of E. utilis (range, 0.5-9.8) across all Brazilian peppertree range in the United States. The potential for establishment of E. utilis and its probable distribution in the continental United States was examined.

Invasive species are believed to spread through a process of stratified dispersal consisting of short-distance diffusive spread around established foci and human mediated long-distance jumps. Brazilian peppertree (Schinus terebinthifolius), native to South America, was introduced twice as an ornamental plant into Florida, USA, just over 100 years ago. A previous study indicated that these two introductions were from genetically differentiated source populations in the native range. In this study, we took advantage of these contrasting genetic signatures to study the spatial spread of Brazilian peppertree across its entire range in Florida. A combination of spatial genetic and geostatistical analyses using chloroplast and nuclear microsatellite markers revealed evidence for both diffusive dispersal and long-distance jumps. Chloroplast DNA haplotype distributions and extensive bands of intra-specific hybridization revealed extensive dispersal by both introduced populations across the state. The strong genetic signature around the original introduction points, the presence of a general southeast to northwest genetic cline, and evidence for short-distance genetic spatial autocorrelation provided evidence of diffusive dispersal from an advancing front, probably by birds and small mammals. In the northernmost part of the range, there were patches having a high degree of ancestry from each introduction, suggesting long-distance jump dispersal, probably by the movement of humans. The evidence for extensive movement throughout the state suggests that Brazilian peppertree will be capable of rapidly recolonizing areas from which it has been eradicated. Concerted eradication efforts over large areas or the successful establishment of effective biocontrol agents over a wide area will be needed to suppress this species.

Brazilian peppertree (Schinus terebinthifolius) is a woody perennial that has invaded much of Florida. This native of northeastern Argentina, Paraguay, and Brazil was brought as an ornamental to both the west and east coasts of Florida at the end of the 19th century. It was recorded as an invader of natural areas in the 1950s, and has since extended its range to cover over 280 000 ha. Our goals were to understand the history of this invasion, as one step toward understanding why this exotic was so successful, and ultimately to improve development of biological control agents. We sampled plants from the native and exotic ranges, particularly Florida, and genotyped these individuals at nuclear and chloroplast loci. Nuclear microsatellite and cpDNA loci reveal strong genetic population structure consistent with limited dispersal in the introduced and native ranges. Bayesian clustering of microsatellite data separates the east and west coast plants in Florida into distinct populations. The two chloroplast haplotypes found in Florida are also concordant with this separation: one predominates on the east coast, the other on the west coast. Analysis of samples collected in South America shows that haplotypes as distinct as the two in Florida are unlikely to have come from a single source population. We conclude that the genetic evidence supports two introductions of Brazilian peppertree into Florida and extensive hybridization between them. The west coast genotype likely came from coastal Brazil at about 27 degrees south, whereas the east coast genotype probably originated from another, as yet unidentified site. As a result of hybridization, the Florida population does not exhibit low genetic variation compared to populations in the native range, possibly increasing its ability to adapt to novel environments. Hybridization also has important consequences for the selection of biocontrol agents since it will not be possible to identify closely co-adapted natural enemies in the native range, necessitating more extensive host testing.

BVA 2 mosquito larvicide was evaluated in laboratory pan tests against 3rd-instar Aedes taeniorhynchus (Wied.), Culex quinquefasciatus Say, and Culex nigripalpus Theobald larvae. BVA 2 was as effective as the standard, GB-1111, at 14 liters/ha (> 99.1% vs. 99.8%). In small field plot tests BVA 2 mosquito larvicide applied at 28 liters/ha was as effective as GB-1111 (99.0% vs. 99.8%) 24 h posttreatment. Operationally, applied by helicopter at 46.8 liters/ha, BVA 2 mosquito larvicide was more effective (> 90%) in the slightly less vegetated site than in the heavily vegetated site. As a pupicide applied at 14 liters/ha in laboratory pan tests, no significant differences were noted between BVA 2 mosquito larvicide and GB-1111 against Ae. taeniorhynchus, Cx. quinquefasciatus, and Cx. nigripalpus pupae.

Waste tires and other types of artificial containers were sampled for immature Aedes to monitor changes in the occurrence of Aedes aegypti (L.) and Aedes albopictus (Skuse) in Florida. The initial invasion and spread of Ae. albopictus in Florida occurred in the northern part of Florida. Throughout this region, major declines in the abundance of Ae. aegypti have been associated with the expansion of Ae. albopictus in both urban and rural areas. Generally, the same results have occurred in central Florida, but at some urban locations Ae. aegypti has remained a common mosquito long after the arrival of Ae. albopictus. In southeastern Florida, Ae. aegypti is currently the dominant container-inhabiting Aedes in urban areas, whereas sites dominated by Ae. albopictus are in rural settings or in undeveloped tracts of land within urban or suburban areas. At some locations, immature Ae. albopictus were found in the same containers with another exotic mosquito, Ae. bahamensis Berlin. The persistence of thriving Ae. aegypti populations in urban areas of southern Florida indicates that Ae. albopictus might not become the dominant container Aedes in these habitats, at least not to the extent that it has in the northern part of the state.