Baseline Susceptibility and Cross Resistances of Some New Acaricides in the European Red Mite, Panonychus ulmi*

We have developed baseline susceptibility values for four new acaricides: bifenazate, acequinocyl, spirodiclofen and etoxazole for eggs or adult females of a susceptible laboratory population of Panonychus ulmi (Koch) (Acari: Tetranychidae). Further, we have tested diagnostic concentrations of each acaricide against populations resistant to organochlorine, organotin or IGR-type acaricides. Resistance to etoxazole (ca. 4-fold) was identified in populations resistant to the IGRs clofentezine and hexythiazox. *The Canadian Crown’s right to retain a non-exclusive, royalty-free licence in and to any copyright is acknowledged.     

Maintaining <Emphasis Type="Italic">Psoroptes ovis</Emphasis> (Acari: Psoroptidae) off-host in the laboratory

Feeding and maintaining sheep scab mites off-host is an important step towards achieving a safer, environmentally-friendly means of controlling sheep scab disease. The test arena developed by Thind and Muggleton (Exp Appl Acarol 22:543–552, 1998) has been adapted for feeding and maintaining Psoroptes ovis off-host. The test arenas are simple to construct and use, and escape-proof to all stages of mites. The performance of the test arenas was assessed by determining the survival of the scab mites at 33 and 36°C and >95% r.h. on different diets. With this test arena the best reported mean survival of 10.3 days was achieved with both females and nymphs at a temperature of 33°C on a diet of sheep serum; the mean maximum survival of females at these conditions was 18.8 days, which is at least a threefold improvement on previous reports. With further development it may be possible to adapt the test arena for assessing both slow and fast acting agents for controlling sheep scab. The British Crown’s right to retain a non-exclusive, royalty-free licence in and to any copyright is acknowledged.     

32P uptake in three submerged aquatic plant species

Summary Highest uptake of³²P by young shoots of three plant species was observed and lowest by old ones. The uptake of³²P was highest inHydrilla shoots, followed byVallisneria andPotamogeton.Kinetin (0.23 mM) pretreatment (24 h) increased the uptake of³²P, while 0.69 mM ethrel or 0.075 mM ABA decreased it in all species.³²P was transported to the largest extent to the young shoots of the submerged plants and to the smallest extent to the old ones by kinetin pretreatment. Kinetin enhanced the uptake of³²P most inHydrilla shoots, followed byVallisneria andPotamogeton. Ethrel diminished³²P uptake most inPotamogeton shoots and to the smallest extent inHydrilla, while ABA lowered it most inHydrilla shoots and to the smallest extent inPotamogeton. Kinetin, ethrel and ABA can modify the uptake of³²P of these aquatic plants.     

Expression of elastinolytic activity among isolates inAspergillus SectionFlavi

A survey of the distribution of elastinolytic potential among 32 culture collection isolates ofAspergillus flavus, A. oryzae, A. parasiticus, A. sojae, A. nomius, andA. tamarii revealed this character to be highly conserved withinAspergillus SectionFlavi. Furthermore, 144 isolates ofA. flavus from environmental samples from six separate regions of the United States produced elastase on solid medium. Most previously described polymorphisms in elastinolytic potential were attributed to the toxicity of borate buffers. Replacement of borate with HEPES (N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid) resulted in detection of elastase production on solid medium by all tested fungal isolates except two that had been in culture over 50 years. In liquid culture, only isolates ofA. flavus, A. tamarii, andA. oryzae accumulated elastase activity. Although isoelectric focusing revealed only one isoform (pI 9.0) of elastase in these culture filtrates, elastinolytic activity in filtrates was partially inhibited by both 1,10-phenanthrolene (2 mM) and phenylmethylsulfonylfluoride (2 mM), suggesting the presence of both metallo and serine elastinolytic proteinases.Abbreviation IEF isoelectric focusing The US Government's right to retain a non-exclusive, royalty-free licence to any copyright is acknowledged.     

Population trends and flight behavior of the American burying beetle, Nicrophorus americanus (Coleoptera: Silphidae), on Block Island, RI

The endangered American burying beetle, Nicrophorus americanus, was monitored on Block Island, RI, USA, from 1991–2003 using mark-recapture population estimates of adults collected in pitfall traps. Populations increased through time, especially after 1994 when a program was initiated that provided carrion for beetle production. Beetle captures increased with increasing temperature and dew point, and decreased with increasing wind speed. Short distance movement was not related to wind direction, while longer distance flights tended to be downwind. Although many individuals flew considerable distances along transects, most recaptures were in traps near the point of release. These behaviors probably have counterbalancing effects on population estimates.The U.S. Goverment's right to retain a non-exclusive, royalty-free license in and to any copyright is acknowledged.     

Enhanced root system C-sink activity,water relations and aspects of nutrient acquisition in mycotrophic Bouteloua gracilis subjected to CO2 enrichment

In order to better elucidate fixed-C partitioning, nutrient acquisition and water relations of prairie grasses under elevated [CO₂], we grew the C₄ grass Bouteloua gracilis (H.B.K.) lag ex Steud. from seed in soil-packed, column-lysimeters in two growth chambers maintained at current ambient [CO₂] (350 μL L⁻¹) and twice enriched [CO₂] (700 μL L⁻¹). Once established, plants were deficit irrigated; growth chamber conditions were maintained at day/night temperatures of 25/16°C, relative humidities of 35%/90% and a 14-hour photoperiod to simulate summer conditions on the shortgrass steppe in eastern Colorado. After 11 weeks of growth, plants grown under CO₂ enrichment had produced 35% and 65% greater total and root biomass, respectively, and had twice the level of vesicular-arbuscular mycorrhizal (VAM) infection (19.8% versus 10.8%) as plants grown under current ambient [CO₂]. The CO₂-enriched plants also exhibited greater leaf water potentials and higher plant water use efficiencies. Plant N uptake was reduced by CO₂ enrichment, while P uptake appeared little influenced by CO₂ regime. Under the conditions of the experiment, CO₂ enrichment increased root biomass and VAM infection via stimulated growth and adjustments in C partitioning below-ground. The U.S. Government right to retain a non-exclusive, royalty free licence in and to any copyright is acknowledged. The U.S. Government right to retain a non-exclusive, royalty free licence in and to any copyright is acknowledged.     

Caste, Sex and Strain of Honey Bees (Apis mellifera) Affect Infestation with Tracheal Mites (Acarapis woodi)*

Worker honey bees from genetic strains selected for being resistant (R) or susceptible (S) to tracheal mites typically show large differences in infestation in field colonies and in bioassays that involve controlled exposure to infested bees. We used bioassays exposing newly emerged individuals to infested workers to compare the propensity for tracheal mites to infest queens, drones and workers from R and S colonies. In tests with queens, newly emerged R and S queens were either simultaneously confined in infested colonies (n = 95 and 87 respectively), or individually caged with groups of 5–20 infested workers (n = 119 and 115 respectively). Mite prevalence (percentage of individuals infested) and abundance (foundress mites per individual) after 4–6 days did not differ between R and S queens. In another test, five newly emerged drones and workers from both an R and an S colony, and a queen of one of the two strains, were caged in each of 38 cages with 20 g of workers infested at 60–96% prevalence. Infestations of the R queens (n = 17) and S queens (n = 19) did not differ significantly, but R workers had half the mite abundance of S workers, while R drones received about a third more migrating mites than S drones. In tests to evaluate possible mechanisms, removal of one mesothoracic leg from R and S workers resulted in 2- to 10-fold increase in mite abundance on the treated side, but excising legs did not affect infestation of the corresponding tracheae in drones. This suggests that differences in infestation between R and S workers, but not drones, are largely determined by their ability to remove mites through autogrooming. If autogrooming is the primary mechanism of colony resistance to tracheal mites, selection for resistance to tracheal mites using infestation of hemizygous drones may be inefficient. *The U.S. Government’s right ot retain a non-exclusive, royalty-free licence in and to any copyright is acknowledged.     

Spatial Relationships Between an Introduced Snapper and Native Goatfishes on Hawaiian Reefs*

It has been suggested that the introduced blueline snapper (Lutjanus kasmira, Family: Lutjanidae) may adversely affect populations of native fishery species in Hawai’i through competition for spatial or dietary resources, or through predation on young fish. We studied the habitat use patterns of L. kasmira and several native reef fish species using direct observation by SCUBA divers. Habitat use patterns of the yellowtail goatfish (Mulloidichthys vanicolensis, Family: Mullidae) were most similar to those of L. kasmira. Both species were primarily found low in the water column and were closely associated with areas of vertical relief. Individual M. vanicolensis were found higher in the water column when L. kasmirawere present, but L. kasmira were not similarly affected by M. vanicolensis. This finding suggests asymmetrical competition for shelter, in which the dominant L. kasmira displaces M. vanicolensis farther into the water column. This displacement from the protection of the reef could increase the vulnerability of M. vanicolensisto predators and fishers. *The US Government’s right to retain a non-exclusive, royalty-free licence in and to any copyright is acknowledged.     

Effects of natural shade on soybean thylakoid membrane composition

The effect of natural shade on chloroplast thylakoid membrane activity and composition was examined for soybean (Glycine Max. cv. Young) grown under field conditions. Plots with high (10 plants m^–1 row) or low (1 plant m^–1 row) plant density were established. Expanding leaves were tagged at 50, 58 and 65 days after planting (DAP). At 92 DAP, tagged leaves were used as reference points to characterize canopy light environments and isolate thylakoid membranes. Light environments ranged from a photosynthetic photon flux density (PPFD) of 87% of full sun to a PPFD of 10% of full sun. The decline in PPFD was accompanied by an increase in the far-red/red (735 nm/645 nm) ratio from 0.9 to approximately six. The major effects of shade on chloroplast thylakoid membranes were a reduction in chloroplast coupling factor and a shift in light-harvesting capacity from Photosystem I to Photosystem II. Photosynthetic electron transport capacity was not affected by differences in PPFD, but was 20 to 30% higher in the 1 plant m^–1 row treatment. The plant density effect on electron transport was associated with differences in plastocyanin concentration, suggesting that plastocyanin is a limiting factor in soybean. Shade did not have a significant effect on the concentration of Photosystem II, Cyt b₆f, or Photosystem I complexes.Abbreviations CF₁ chloroplast coupling factor - DAP days after planting - DBMIB 2,5-dibromo-3-methyl-6-isopropyl-p-benzoquinone - DCIP 2,6-dichlorophenolindophenol - FR/R far-red/red - PBS 10 mM sodium phosphate (pH 7.0), 150 mM NaCl - PPFD photosynthetic photon flux density - PS I Photosystem I - PS II Photosystem II - P700 reaction center of Photosystem I - Rubisco ribulose-1,5-bisphosphate carboxylase/oxygenase - TBS 20 mM Tris-HCl (pH 7.5), 500 mM NaCl - TTBS 20 mM Tris-HCl (pH 7.5), 500 mM NaCl, 0.05% (w/v) polyoxyethylenesorbitan monolaurate (Tween-20) The US Government right to retain a non-exclusive, royalty-free licence in and to any copyright is acknowledged.The US Government right to retain a non-exclusive, royalty-free licence in and to any copyright is acknowledged.     

California’s Reaction to <Emphasis Type="Italic">Caulerpa taxifolia</Emphasis>: A Model for Invasive Species Rapid Response*

The invasive marine alga Caulerpa taxifolia was discovered June 12, 2000, in California at Agua Hedionda Lagoon. Due to a 15-year history of spread in the Mediterranean Sea, C. taxifolia had already been placed on the US Federal Noxious Weed list in 1999. Awareness of this threat greatly facilitated consensus building and setting clear eradication goals among a large number of state, federal and local agencies as well as private groups and non-governmental organizations (NGOs) that became the ‘Southern California Caulerpa Action Team’ (SCCAT). Field containment and treatments began 17 days after the discovery due to: (1) timely identification and notification of the infestation; (2) the proactive staff of the San Diego Regional Water Quality Control Board who deemed this invasion tantamount to an ‘oil spill’, thus freeing up emergency funding; (3) the mobilization of diver crews already working at the site. Three well-integrated components of this rapid response have resulted in an effective eradication program: (a) expertise and knowledge on the biology of C. taxifolia; (b) knowledge on the uses, ‘ownership’ and characteristics of the infested site; (c) knowledge and experience in the implementation of aquatic plant eradication. Together, with the requisite resources (approximately $US1.2 million per year), this approach has resulted in containment, treatment and excellent progress toward eradication of C. taxifolia. Successful rapid response to other aquatic invasive species will require similar readiness to act, and immediate access to adequate funding. The US Government’s right to retain a non-exclusive, royalty-free licence in and to any copyright is acknowledged.     

Crop-to-crop Gene Flow using Farm Scale Sites of Oilseed Rape (<Emphasis Type="Italic">Brassica napus</Emphasis>) in the UK

From 2000–2003 a range of Farm Scale Evaluation (FSE) trials were established in the UK to assess the effect of the release and management of herbicide tolerant (HT) crops on the abundance and diversity of farmland wildlife compared with their conventionally managed non-GM-equivalents. The objective of this research project was to investigate gene flow within the winter (WOSR) and spring oilseed rape (SOSR) FSE trials and to develop a statistical model for the prediction of cross-pollination frequency that can be used to evaluate current separation distance guidelines. Seed samples were collected from the non-GM half of the trial sites and were tested for evidence of cross-pollination from the GM HT halves using a quantitative PCR assay specific to the HT (bar) gene. Rates of cross-pollination were found to decrease rapidly with increasing distance from the GM source. The quantitative data were subjected to statistical analysis and a two-step model was found to provide the best fit for the data. Significant differences were found between the results for WOSR, SOSR and varietal association (VA) crops. The model predicted that the %GM content (including upper 95% confidence limits) of a sample taken at a distance of 50 m away from the GM source would be 0.04% (0.84%) for WOSR, 0.02% (0.39%) for SOSR, 0.77% (21.72%) for WOSR VA and 0.37% (5.18%) for SOSR VA. The data and models presented here are discussed in the context of necessary separation distances to meet various possible thresholds for adventitious presence of GM in OSR. The British Crown's right to retain a non-exclusive, royalty-free licence in and to any copyright is acknowledged.     

Propagule type influences competition between two submersed aquatic macrophytes

Summary Glasshouse competition experiments with Hydrilla verticillata (L.f.) Royle indicate that plants grown from turions are weaker competitors than those grown from tubers, when compared to the widely distributed macrophyte, Potamogeton pectinatus L. These results support an earlier hypothesis about the importance of propagule size for predicting the outcome of plant competition (Grace 1985; Schaffer and Gadgil 1980). Results of outdoor growth experiments indicate that even though Hydrilla plants from turions are relatively weaker competitors, they are able to grow succesfully in an existing macrophyte bed composed of either, P. pectinatus or P. gramineus. During the early stages of Hydrilla invasion into an area of existing macrophytes, native plants may coexist with Hydrilla. However, once the abundance of Hydrilla tubers in the sediment increases, Hydrilla may displace existing plants.     

Analysis of ribosomal DNA restriction patterns in the genusKluyveromyces

Riboprinting was used to determine the relationships among strains belonging to 15 species of the genusKluyveromyces. The small subunit ribosomal RNA gene (SSU rDNA) was amplified using the Polymerase Chain Reaction (PCR) and subjected to a battery of nine restriction enzymes. Similarity coefficients between strains were calculated based on shared and unique restriction fragments. Cluster analysis revealed three major groups that generally correlated with previously reported relationships based on other molecular data. Variations in SSU rDNA restriction fragments may be used for differentiation of theKluyveromyces strains included in this study.The U.S. Government right to retain a non-exclusive, royalty free licence in and to any copyright is acknowledged.     

The mechanism of Rubisco activase: Insights from studies of the properties and structure of the enzyme

Rubisco, the primary carboxylating enzyme in photosynthesis, must be activated to catalyze CO₂ fixation. The concept of an activase, a specific protein for activating Rubisco, was first introduced in 1985 based largely on biochemical and genetic studies of a high CO₂-requiring mutant of Arabidopsis (Salvucci et al. (1985) Photosynth Res 7: 193–201). Over the past ten years, details about the occurrence, structure, and properties of Rubisco activase have been elucidated. However, the mechanism of action of Rubisco activase remains elusive. This review discusses the need for and function of Rubisco activase and summarizes information about the properties and structure of Rubisco activase. The information is evaluated in the context of the mechanism of Rubisco activase.Abbreviations CA1-P carboxyarabinitol 1-phosphate - PS photosystem - Rubisco ribulose 1,5-bisphosphate carboxylase/oxygenase - RuBP ribulose 1,5-bisphosphate - XuBP xylulose 1,5-bisphosphate The US Government right to retain a non-exclusive, royalty-free licence in and to any copyright is acknowledged.     

Occurrence of aflatoxin in three maize (<Emphasis Type="Italic">Zea mays</Emphasis> L.) hybrids over 5 years in Northern Mississippi

Aflatoxins are produced as secondary metabolites under conducive climatic conditions by Aspergillus flavus. The incidence of aflatoxin varies with environmental conditions, genotype, and location. An expanded understanding of the interaction of the plant, fungus, and weather conditions is needed to further elucidate the field infection process of maize by A. flavus and subsequent aflatoxin contamination. One of the problems in evaluating maize hybrids for resistance to kernel infection and aflatoxin contamination is identifying a time period and environmental conditions that are most advantageous. Three maize genotypes (Pioneer Brand 3223, Mo18W × Mp313E, and Mp313E × Mp420) were evaluated from 1998 to 2002 in response to A. flavus inoculation and aflatoxin contamination and weather conditions favorable for aflatoxin contamination were identified. The highest aflatoxin levels were observed in 1998 and 2000 (1186 and 901 ng g⁻¹; P < 0.0001); while the lowest levels were detected in 1999 (39 ng g⁻¹). Pioneer 3223 had significantly higher levels (1198 ng g⁻¹) than Mp313E × Mp420 (205 ng g⁻¹), and Mo18W ×Mp313E (161 ng g⁻¹; P < 0.0001). The hybrids had six weather-related variables in common that were positively correlated with aflatoxin accumulation. Four of these occurred during 65–85 days after planting and were temperature-related. These results suggest that regardless of the hybrid’s maturity or physiological development, the time from 65 to 85 days after planting may be indicative of a period of stress which leads to greater aflatoxin accumulation at harvest. The U.S. Government's right to retain a non-exclusive, royalty-free license in and to any copyright is acknowledged.     

The importance of streamside sandbars to ground beetle (Coleoptera, Carabidae) communities in a deciduous forest

We used pitfall traps to sample ground beetles on sandbars along a small woodland stream and in the adjacent floodplain forest (Oglethorpe Co., GA, USA). We captured a total of 1,477 ground beetles representing 41 species. Twenty-two species were exclusive to sandbars, while eight were found only in the forested habitat. Ground beetles were captured in significantly greater numbers from sandbars, especially Brachinus janthinipennis and Omophron americanum. The B. janthinipennis record represents a new state record for the species. This study demonstrates that many unique species can be found in specialized microhabitats and emphasizes the need for biodiversity assessment surveys to include a wide range of these microhabitats within a survey area. In addition, it appears that many generalist forest species might use sandbars seasonally to exploit available resources. The U.S. Government's right to retain a non-exclusive, royalty-free license in and to any copyright is acknowledged.     

Molecular evidence for a novel <Emphasis Type="Italic">Coxiella</Emphasis> from <Emphasis Type="Italic">Argas monolakensis</Emphasis> (Acari: Argasidae) from Mono Lake,California, USA

Argasid ticks are vectors of viral and bacterial agents of humans and animals. Recent reports indicate that some ornithophilic argasids harbored rickettsial agents. A Nearctic tick, Argas monolakensis Schwan, Corwin, Brown is ornithophilic and has not previously been examined for rickettsial agents. Thirty adult A. monolakensis were tested by PCR for DNA from Rickettsia or Coxiella. Amplicons from a Coxiella sp. that were divergent from Coxiella burnetii were detected in 16/30 A. monolakensis. These molecular isolates were similar but not identical to C. burnetii, the Coxiella spp. of other ticks, and “Coxiella cheraxi” a pathogen of crayfish. The U.S. Government’s right to retain a non-exclusive, royalty-free license in and to any copyright is acknowledged.     

Assessment of Monitoring Methods for Early Detection of Three Species of Storage Mite in Bulk Oilseed Rape

Two types of trap, the BT Trap and PC^TM pitfall cone trap, were evaluated against the most widely used method of sampling and sieving for their ability to detect low numbers of storage mites (Acarus siro, Tyrophagus longior and Lepidoglyphus destructor) in bulk oilseed rape, under UK maritime conditions. In addition, a synthetic lure (2-nonanone) was incorporated into the two types of trap to assess whether its presence improved trapping performance. The BT traps and PC traps were significantly more effective in detecting low numbers of mites of all species compared with sampling and sieving. The PC trap with synthetic lure was the most effective method. As the PC trap is already widely used for monitoring insects in cereal bulks in the UK, extending its application to include oilseed rape, and to detect mites, would be a logical and cost effective extension of its use. The British Crown's right to retain a non-exclusive, royalty-free license in and to any copyright is acknowledged.     

Examination of the Biological Effects of High Anionic Peroxidase Production in Tobacco Plants Grown under Field Conditions. I. Insect Pest Damage

At least 25 wild type and high peroxidase tobacco Nicotiana tabacum L. plants were examined semiweekly over several weeks for pest insect distribution and damage in a 2 year field study. Incidence and/or severity of naturally occurring caterpillar damage (dingy cutworm (Feltia ducens Walker), black cutworm (Agrotis ipsilon (Hufnagel), tobacco hornworm (Manduca sexta L.), and false tobacco budworm (= corn earworm Helicoverpa zea (Boddie)) was significantly reduced at several sample dates for high peroxidase vs. wild type plants. These results parallel those of prior laboratory studies with caterpillars. The number of adult whiteflies (Trialeurodes vaporariorum (Westwood) per plant was significantly reduced on high peroxidase compared to wild type plants on most sample dates in both years. The number of plants with leaves containing >100 aphids (primarily Myzus persicae Sulzer) per leaf on high peroxidase plants was significantly lower that on wild type plants after an equivalent invasion period in both years. A significantly higher proportion of aphids were found dead on leaf five of high peroxidase compared to wild type plants at most sample dates in both years. These results indicate that high peroxidase plants have resistance to a wide range of insects, implicating this enzyme as a broad range resistance mechanism. The U.S. Government’s right to retain a non-exclusive, royalty-free license in and to any copyright is acknowledged.     

Engineering Disease Resistant Cattle

Mastitis is a disease of the mammary gland caused by pathogens that find their way into the lumen of the gland through the teat canal. Mammary gland infections cost the US dairy industry approximately $2 billion dollars annually and have a similar impact in Europe. In the absence of effective treatments or breeding strategies to enhance mastitis resistance, we have created transgenic dairy cows that express lysostaphin in their mammary epithelium and secrete the antimicrobial peptide into milk. Staphylococcus aureus, a major mastitis pathogen, is exquisitely sensitive to lysostaphin. The transgenic cattle resist S. aureus mammary gland challenges, and their milk kills the bacteria, in a dose dependent manner. This first step in protecting cattle against mastitis will be followed by introduction of other genes to deal with potential resistance issues and other mastitis causing organisms. Care will be taken to avoid altering milk’s nutritional and manufacturing properties. Multi-cistronic constructs may be required to achieve our goals as will other strategies possibly involving RNAi and gene targeting technology. This work demonstrates the possibility of using transgenic technology to address disease problems in agriculturally important species. The U.S. Government's right to retain a non-exclusive, royalty-free license in and to any copyright is acknowledged.