The passionvine mealybug,Planococcus minor (Maskell) (Hemiptera: Pseudococcidae), and its natural enemies in the cocoa agroecosystem in Trinidad

Planococcus minor (Maskell) is native to South Asia, but it is also present in several Neotropical locations including the island of Trinidad in the southern Caribbean. The mealybug poses a serious threat to uninfested countries in this region as well as the mainland U.S. As part of an effort to gather much needed information on P. minor, 33 cocoa (Theobroma cacao L.) field sites on the island were surveyed in 2006 with a view to assess the occurrence and pest status of the mealybug. P. minor was identified from 20 field sites, indicating that it was well distributed across the island on this crop, which appeared to be a reliable indicator host plant. Infestation levels were generally low and populations were sparsely distributed across the field sites categorized into three habitat types. The following year, nine field sites were surveyed for natural enemies of P. minor using laboratory-infested potatoes in sentinel traps. Species from four insect orders and six families were collected and identified. The major predators belonged to the families Cecidomyiidae and Coccinellidae. Two primary parasitoids, Leptomastix dactylopii Howard (Encyrtidae) and Coccidoxenoides perminutus (Girault) (=Pauridia peregrina Timberlake, =Coccidoxenoides peregrinus (Timberlake)) (Encyrtidae), were reared from different mealybug stages, along with several hyperparasitoids. The primary parasitoids were probably introduced fortuitously. These diverse natural enemies were recovered throughout the sampling period from the different habitat types. The identification of key natural enemies associated with P. minor has important implications for the implementation of biological control in newly infested areas.     

Evaluation of predatory mites and Acramite for control of twospotted spider mites in strawberries in north central Florida

Greenhouse and field experiments were conducted from 2003 to 2005 to determine the effectiveness of two predatory mite species, Phytoseiulus persimilis Athias-Henriot and Neoseiulus californicus (McGregor), and a reduced-risk miticide, Acramite 50 WP (bifenazate), for control of twospotted spider mite, Tetranychus urticae Koch, in strawberries (Fragaria x ananassa Duchesne). In greenhouse tests, three treatments consisting of releases of P. persimilis, N. californicus, and an untreated control were evaluated. Both species of predatory mites significantly reduced twospotted spider mite numbers below those found in the control during the first 3 wk of evaluation. However, during week 4, twospotted spider mite numbers on the plants treated with P. persimilis increased and did not differ significantly from the control. Field studies used releases of P. persimilis and N. californicus, applications of Acramite, and untreated control plots. Both N. californicus and P. persimilis significantly reduced populations of twospotted spider mite below numbers recorded in the control plots. During the 2003-2004 field season P. persimilis took longer than N. californicus to bring the twospotted spider mite population under control (< 10 mites per leaflet). Acramite was effective in reducing twospotted spider mite populations below 10 mites per leaflet during the 2003-2004 field season but not during the 2004-2005 field season, possibly because of a late application. These findings indicate that N. californicus releases and properly timed Acramite applications are promising options for twospotted spider mite control in strawberries for growers in north Florida and other areas of the southeast.     

Histological studies on cultured canine heart valves recovered from −196 °C

Adult canine heart valves have been frozen to ?196 °C, (0.5 to 0.7 °C/min from 0 to ?100 °C) with 10% DMSO ($\text{v}\text{v}$), stored, thawed at ~150 °C/min, and then cultured for 9 to 12 days. A histological analysis of sections derived from several valves indicates viability, but with a not inconsiderable loss of stromal fibrocytes and some damage to the endothelial lining. The practicality of freezing valve tissue for banking will have to be looked at critically, before valve transplants can be considered as a possible alternative to the well established use of mechanical valve prosthesis. However, demonstrating viability of heart valve tissue extends the range of tissues that are amenable to cryopreservation.     

Effects of soil moisture and temperature on reproduction and development of twospotted spider mite (Acari: Tetranychidae) in strawberries

The effects of soil moisture and temperature on the reproduction of twospotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae), were examined in laboratory and field tests in strawberries, Fragaria x ananassa Duchesne, in Florida. Different soil moisture levels (low, moderate, and high) were compared to determine how soil moisture affects the reproduction and development of twospotted spider mite. In addition to soil moisture, different irrigation techniques (drip versus drip/overhead) were compared to determine their effects on twospotted spider mite reproduction as well as the incidence of angular leaf spot, Xanthomonas fragaria Kennedy & King disease. Similar studies were conducted to determine how different temperatures (18, 27, and 35 degrees C) affect the reproduction and development of twospotted spider mites. In the laboratory, low soil moisture as well as temperatures >27 degrees C promoted twospotted spider mite development. A similar trend was observed in a field study with low soil moisture promoting twospotted spider mite reproduction during the early season (11 November--8 December). Irrespective of moisture levels, a significantly higher incidence of X. fragaria was recorded in treatments with drip/overhead irrigation systems compared with drip irrigation. Implications for management of soil moisture levels are discussed with respect to the abundance of twospotted spider mite and X. fragaria in strawberries.     

Identification of calmodulin and MlcC as light chains for Dictyostelium myosin-I isozymes

Dictyostelium discoideum express seven single-headed myosin-I isozymes (MyoA-MyoE and MyoK) that drive motile processes at the cell membrane. The light chains for MyoA and MyoE were identified by expressing Flag-tagged constructs consisting of the motor domain and the two IQ motifs in the neck region in Dictyostelium. The MyoA and MyoE constructs both copurified with calmodulin. Isothermal titration calorimetry (ITC) showed that apo-calmodulin bound to peptides corresponding to the MyoA and MyoE IQ motifs with micromolar affinity. In the presence of calcium, calmodulin cross-linked two IQ motif peptides, with one domain binding with nanomolar affinity and the other with micromolar affinity. The IQ motifs were required for the actin-activated MgATPase activity of MyoA but not MyoE; however, neither myosin exhibited calcium-dependent activity. A Flag-tagged construct consisting of the MyoC motor domain and the three IQ motifs in the adjacent neck region bound a novel 8.6 kDa two EF-hand protein named MlcC, for myosin light chain for MyoC. MlcC is most similar to the C-terminal domain of calmodulin but does not bind calcium. ITC studies showed that MlcC binds IQ1 and IQ2 but not IQ3 of MyoC. IQ3 contains a proline residue that may render it nonfunctional. Each long-tailed Dictyostelium myosin-I has now been shown to have a unique light chain (MyoB-MlcB, MyoC-MlcC, and MyoD-MlcD), whereas the short-tailed myosins-I, MyoA and MyoE, have the multifunctional calmodulin as a light chain. The diversity in light chain composition is likely to contribute to the distinct cellular functions of each myosin-I isozyme.     

Quantitative high-throughput measurement of gene expression with sub-zeptomole sensitivity by capillary electrophoresis

Microarray technologies have provided the ability to monitor the expression of whole genomes rapidly. However, concerns persist with regard to quantitation and reproducibility, and the detection limits for individual genes in particular arrays are generally unknown. This article describes a semiautomated PCR-based technology, Q-RAGE, which rapidly provides measurements of mRNA abundance with extremely high sensitivity using fluorescent detection of specific products separated by capillary electrophoresis. A linear relationship between template concentration and fluorescent signal can be demonstrated down to template concentrations in the low aM region, corresponding to approximately 0.04 zmol (24 molecules) per reaction. The technique is shown to be quantitative over five orders of magnitude of template concentration, and average mRNA abundances of approximately 0.01 molecule per cell can be detected. A single predefined set of 320 primers provides 90-95% coverage of all eukaryotic genomes. Analysis of a set of 19 p53-regulated genes in untreated cultures of normal human epithelial cells, derived from three different tissues, revealed a 600-fold range of apparent constitutive expression levels. For most of the genes assayed, good correlations were observed among the expression levels in normal mammary, bronchial, and epidermal epithelial cells.     

Effects of southern highbush blueberry cultivar and treatment threshold on flower thrips populations

In Florida, southern highbush (SHB) blueberries (Vaccinium corymbosum L. x Vaccinium darrowi Camp) are grown for a highly profitable early season fresh market. Flower thrips are the key pest of SHB blueberries, and Frankliniella bispinosa (Morgan) is the most common species found. Flower thrips injure blueberry flowers by feeding and ovipositing in all developing tissues. These injuries can lead to scarring of developing fruit. The objectives of this study were to determine the relationship between thrips and yield in different SHB blueberry cultivars and to determine an action threshold. Experiments were conducted during early spring 2007 and 2008 on four farms; a research farm in Citra, FL; and three commercial farms, two in Hernando Co., FL., and one in Lake Co., FL. At the Citra farm, 'Emerald', 'Jewel', 'Millennia', and 'Star' blueberries were compared in 2007, and all but Star were compared in 2008. On the Hernando and Lake Co. farms, two treatment thresholds (100 and 200 thrips per trap) and an untreated control and four cultivars (Emerald, Jewel, Millennia, and 'Windsor') were compared. Emerald consistently had more thrips per trap and per flower than the other cultivars on all four farms. However, this did not always lead to an increase in fruit injury. Thrips numbers exceeded the threshold on only one farm in 2007, and there was a significantly lower proportion of injured and malformed fruit in the 100 thrips per trap threshold treatment compared with the control on this farm.     

Global transcriptional response of pig brain and lung to natural infection by Pseudorabies virus

Background  

Pseudorabies virus (PRV) is an alphaherpesviruses whose native host is pig. PRV infection mainly causes signs of central nervous system disorder in young pigs, and respiratory system diseases in the adult.     

Toxicity of imidacloprid-treated spheres to Caribbean fruit fly, Anastrepha suspensa (Diptera: Tephritidae) and its parasitoid Diachasmimorpha longicaudata (Hymenoptera: Braconidae) in the laboratory

No-choice cage tests were used to study the toxicity of imidacloprid-treated spheres to Caribbean fruit fly, Anastrepha suspensa (Loew), and its associated parasitoid, Diachasmimorpha longicaudata (Ashmead), in the laboratory. Three imidacloprid sphere treatments (2, 4, and 8% active ingredient [AI] Provado 1.6 F) and an untreated control sphere (no toxicant) were evaluated against A. suspensa. Throughout the observation period (2-72 h), all concentrations of imidacloprid-treated spheres killed significantly more A. suspensa compared with control spheres. After 4 h of exposure to imidacloprid-treated spheres, significantly more A. suspensa were killed on spheres treated with 8% compared with 2% (AI). At 48 and 72 h, there were no significant differences in the mean number of A. suspensa killed at 2, 4, and 8% (AI), potentially indicating that a period of 24 h was sufficient for flies to ingest a lethal dose of the pesticide. Overall, significantly more A. suspensa males were killed after 72 h of exposure to imidacloprid-treated spheres compared with females. For D. longicaudata, only two imidacloprid sphere treatments, 2 and 4% (AI), and an untreated sphere (control) were evaluated for mortality in cage tests. There were no significant differences in mortality of D. longicaudata between the 2 and 4% (AI) imidacloprid-treated spheres. Both rates killed significantly more D. longicaudata compared with the control. However, after 24, 48, and 72 h of exposure to imidacloprid-treated spheres, significantly more D. longicaudata were killed in cages containing 4% compared with 2% (AI) and untreated control spheres. The study demonstrates the potential use of imidacloprid-treated spheres for control of A. suspensa in areas where it may be difficult to apply broad-spectrum insecticides.