An Improved molecular tool for distinguishing monoecious and dioedious Hydrilla

Two biotypes of hydrilla [Hydrilla verticillata(L.f.) Royle] occur in the United States, a dioecious type centered in the southeast and a monoecious type in the central Atlantic and northeastern states. Ecosystem managers need tools to distinguish the types as the ranges of each type expand and begin to overlap. A molecular tool using the randomly amplified polymorphic DNA (RAPD) procedure is available but its use is limited by a need for reference samples. We describe an alternative molecular tool which uses “universal primers” to sequence the trnL intron and trnL-F intergenic spacer of the chloroplast genome. This sequence yields three differences between the biotypes (two gaps and one single nucleotide polymorphism). A primer has been designed which ends in a gap that shows up only in the dioecious plant. A polymerase chain reaction (PCR) using this primer produces a product for the monoecious but not the dioecious plant

Seed Longevity of Melaleuca quinquenervia: A Burial Experiment in South Florida

Burial and removal techniques with seed bags were used to examine the viability and longevity of Melaleuca quinquenervia seeds at four field sites representing different soil types and hydrological conditions in South Florida. Seed viability was determined over different burial durations in the soil through a combination of germination tests and 2,3,5-triphenyl- tetrazolium chloride (TTC) treatments. Control seeds kept dry at 25 C in the laboratory maintained same viability of ca. 15% over the 3-year study. In the field, seed viability decreased with increased burial duration.(PDF has 4 pages.

Current levels of suppression of waterhyacinth in Florida USA by classical biological control agents

Waterhyacinth, Eichhornia crassipes (Mart.) Solms (Pontederiaceae), has been a global target for classical biological control efforts for decades. In Florida, herbicidal application is the primary control method employed, usually without regard for the activities of the three biological control agents introduced intentionally during the 1970s, namely Neochetina eichhorniae Warner, Neochetina bruchi, Hustache (Coleoptera:Curculionidae), and Niphograpta albiguttalis Warren (Lepidoptera: Crambidae). A series of field experiments from 2008 to 2010 was conducted at four Florida sites using an insecticide-check approach to quantify the current levels of suppression provided by these agents. In the field N. albiguttalis was rarely found while more than 99% of all Neochetina sp. adults were N. eichhorniae. Although it was not possible to disentangle the relative impacts of Neochetina sp. adults from larvae on individual plant variables, the larvae played a major role in reducing plant biomass and the number of inflorescences. Plots exposed to unrestricted herbivory contained 58.2% less biomass and produced 97.3% fewer inflorescences at the end of the experiments. Despite these large reductions, herbivory decreased waterhyacinth coverage by only 16.8% and most of this was attributed to a low-nutrient site where coverage was reduced disproportionately. Overall, coverage trended upwards during the course of the experiments and was always close to 100% when the plots were harvested. Although coverage is a somewhat arbitrary metric, especially for floating plants subject to compression and dispersion, it influences the perception of biological control efficacy which, in turn, directly influences herbicide management decisions in Florida. Despite waterhyacinth populations that now produce less than half as much biomass and up to 98% fewer seeds than before the deployment of biological control agents, the overall approach used to achieve maintenance control of the plant in Florida will probably not change unless new biological control agents, such as Megamelus scutellaris Berg (Hemiptera: Delphacidae), can reduce coverage significantly

Description of the Larva of Lophodiplosis trifida, an Australian Gall Midge (Diptera: Cecidomyiidae) and Biocontrol Agent of Paperbark in

JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact [email protected]. Florida Entomological Society is collaborating with JSTOR to digitize, preserve and extend access to The Florida Entomologist

Should the mirid, Eccritotarsus catarinensis (Heteroptera: Miridae), be considered for release against water hyacinth in the United States of America?

Between one and seven biological control agents have been released against water hyacinth (Eichhornia crassipes (Mart.) Solms) in at least 30 countries, with varied success. A mirid, Eccritotarsus catarinensis (Carvalho) (Heteroptera: Miridae), the most recent agent released, is damaging to the plant on the African continent

Description of the Larva of \u3ci\u3eLophodiplosis trifida\u3c/i\u3e, an Australian Gall Midge (Diptera: Cecidomyiidae) and Biocontrol Agent of Paperbark in Florida, USA

Lophodiplosis trifida Gagné, an Australian gall midge on paperbark, Melaleuca quinquenervia (Myrtaceae), is a recent release in southern Florida for the biological control of that host. The larval stage is described for the first time and compared to that of other Lophodiplosis species. Photos of galls and illustrations of larvae are provided. Second and third instars of L. trifida are unusual among Cecidomyiidae for the lack of setae on most papillae

Ecology of common salvinia, \u3ci\u3eSalvinia minima\u3c/i\u3e Baker, in southern Florida

Populations of the floating macrophyte, Salvinia minima Baker, were assessed over a 39-month period at four sites in southern Florida in order to elucidate the abiotic and biotic factors that influenced their density. These factors included the abundance of other plant species, changes in water depth, water quality, and herbivory by insects. Abiotic factors like temperature, pH, DO, and conductivity varied among sites and, more importantly, over time. The same was true for S. minima biomass, coverage, and condition. Principal component analysis identified four components which together explained 64% of the variability in S. minima biomass. The first component correlated strongly with herbivory from Cyrtobagous salviniae Calder and Sands and Synclita obliteralis (Walker) as well as the abundance of the duckweed Spirodela polyrrhiza (L.) Schleid. Temperature effects were strongly represented in the second principal component. A stepwise regression model that best predicted S. minima biomass incorporated conductivity, insect herbivory, and interspecific plant abundance. Broader dry vs. wet season influences were apparent and linked to temperature, water depth, and conductivity that covaried with S. minima biomass. Sites where water depth changed the most had the least S. minima. Insect herbivory did not increase under more stagnant conditions when plant populations were less mobile. Overall, S. minima populations cycled in southern Florida in response to a shifting array of abiotic and biotic factors. The relative importance of these factors was less clear although the influences of herbivory, temperature, and the presence of other plants were significant

Performance and impact of the biological control agent 'Xubida infusella' (Lepidoptera; Pyralidae) on the target weed 'Eichhornia crassipes' (waterhyacinth) and on a non-target plant,'Pontederia cordata' (pickerelweed) in two nutrient regimes

'Xubida infusella' (Walker) (Lepidoptera: Pyralidae) is potentially a useful biological control agent targeting 'Eichhornia crassipes' (waterhyacinth) in the USA but many regions infested with waterhyasinth are also inhabited by an alternative native host, 'Pontederia cordata' (pickerelweed). Experiments were conducted in Australia to assess the impact of 'X. infusella' on pickerelweed compared to waterhyacinth where both these plants were available and 'X. infusella' had already been released. Overall 'X. infusella' had a greater impact on pickerelweed than on waterhyacinth. More than one larva per plant was required to reduce the total shoot dry weight of waterhyacinth but only one larva per plant reduced the total shoot dry weight of pickerelweed. Insect feeding caused the number of secondary shoots (daughter plants) of pickerelweed to double whereas the number of daughter plants produced by waterhyacinth remained unchanged. We suggest this indicates a considerable impact on pickerelweed rather than effective compensation for insect damage because the shoots produced were very small. Waterhyacinth produced a constant number of daughter plants when fed on by up to three larvae per plant. Hugher nitrogen status of both species of host plant increased the rate of larval development and pupal weight of 'X. infusella'. The weight and fecundity of 'X. infusella' reared on pickerelweed were lower than those reared on waterhyacinth but large numbers of progeny were produced on both plant species. This experiment demonstrates a considerable impact of 'X. infusella' on pickerelweed suggesting this plant is at risk from this agent if released in the USA where pickerelweed is present. The considerable impact on waterhyacinth demonstrates the potential for this insect to contribute to waterhyacinth control in countries where risk assessment favours release