Root Weevil (Coleoptera: Curculionidae) and Ground Beetle (Coleoptera: Carabidae) Immigration into Strawberry Plots Protected by Fence or Portable Trench Barriers

Physical exclusion shows some potential as a novel root weevil control strategy, but barriers to root weevil immigration may also exclude beneficial insects, such as ground beetles. A field study was undertaken in 1997 to assess the impact of two physical barriers—portable plastic trenches and aluminum fences with Teflon tape—on root weevil and ground beetle immigration into plots of strawberry, Fragaria x ananassa (Duchesne). Barypeithes pellucidus (Boheman) and Nemocestes incomptus (Horn), each comprised 43% of the root weevils caught at the site. Most (86%) of the ground beetles caught in control plots were longer than 1 cm, the width of the gap in the portable trench top. Trenches excluded 75 and 63% of B. pellucidus and N. incomptus, respectively, without significantly reducing immigration of large (<1 cm) ground beetles. Fences excluded 65, 84, and 99% of B. pellucidus, N. incomptus, and large ground beetles, respectively. Adding diatomaceous earth to trenches did not increase their efficacy, and fences without Teflon tape excluded ground beetles but not root weevils. The reduction in the population of root weevils and other strawberry pests caused by the use of barriers reduced damage to strawberry plant leaves and increased strawberry plant survival relative to unprotected control plots. Advantages and disadvantages of these physical control tools are discussed with a view to creating superior tools for root weevil exclusion, compatible with an integrated pest management approach. Portable trenches may offer a means of selectively excluding root weevils but not ground beetles

Moisture tempers impairment of adult Otiorhynchus sulcatus (Coleoptera: Curculionidae) climbing ability by fluoropolymer, talc dust, and lithium grease

As part of a project to develop tools for the physical exclusion of flightless root weevils, adult black vine weevils (BVW), Otiorhynchus sulcatus (F.), were placed in open enclosures with smooth walls of glass, plastic or aluminum to test their ability to escape by climbing. Enclosure walls were left untreated or were treated with substances known to reduce insect climbing ability: fluoropolymer, powdered talc and lithium grease. No BVW escapes were observed under dry conditions, but all treatments allowed some escapes under wet conditions, suggesting that moisture helps BVW adults scale treated surfaces. The results help explain the ability of root weevils to overcome physical barriers under field conditions

Importance of Collection Overhangs on the Efficacy of Exclusion Fences for Managing Cabbage Flies (Diptera: Anthomyiidae)

Fine nylon mesh fences (135 cm high) with varying lengths of downward-sloping collection overhangs were evaluated for efficacy in excluding the female cabbage flies Delia radicum (L.) from plots of radish, Raphanus sativus (L.). During three trials conducted in 1994 and 1995, fences without overhangs, fences with 12.5-cm overhangs, or fences with 50-cm overhangs were tested against fences with standard 25-cm overhangs and unfenced control plots. In fenced plots with standard 25-cm overhangs, the mean number of D. radicum females caught on yellow sticky traps placed within plots was 85% less than those caught in corresponding control plots. The mean numbers of D. radicum females caught in fenced enclosures with no overhangs, 12.5-cm overhangs, or 50-cm overhangs, were 61, 67, and 94% less than those caught in corresponding control plots, respectively. The mean proportion of radishes damaged by D. radicum larvae inside enclosures with 25-cm overhangs was 62% less than in corresponding control plots. The mean proportions of radishes damaged inside fences with no overhangs, 12.5-cm overhangs, or 50-cm overhangs were 33, 59, and 81% less than those caught in corresponding control plots, respectively. Results are discussed in terms of defining an appropriate fence design for commercial use

Propfan experimental data analysis

A data reduction method, which is consistent with the performance prediction methods used for analysis of new aircraft designs, is defined and compared to the method currently used by NASA using data obtained from an Ames Res. Center 11 foot transonic wind tunnel test. Pressure and flow visualization data from the Ames test for both the powered straight underwing nacelle, and an unpowered contoured overwing nacelle installation is used to determine the flow phenomena present for a wind mounted turboprop installation. The test data is compared to analytic methods, showing the analytic methods to be suitable for design and analysis of new configurations. The data analysis indicated that designs with zero interference drag levels are achieveable with proper wind and nacelle tailoring. A new overwing contoured nacelle design and a modification to the wing leading edge extension for the current wind tunnel model design are evaluated. Hardware constraints of the current model parts prevent obtaining any significant performance improvement due to a modified nacelle contouring. A new aspect ratio wing design for an up outboard rotation turboprop installation is defined, and an advanced contoured nacelle is provided

Effects of soil type and moisture on emergence of tuber flea beetles, Epitrix Tuberis (Coleoptera: Chrysomelidae) from potato fields

The numbers of adult tuber flea beetles, Epitrix tuberis Gentner, emerging from different soil types in the lower Fraser Valley of British Columbia were compared in 1987 and 1988. Over- wintered beetles (PI) were released at known densities onto caged Russet Burbank potato plants grown in soils with different inorganic, organic, and moisture characteristics. The time from the introduction of PI beetles in June to the mean initial emergence of first generation (FI) beetles ranged from 38 to 47.2 days during the two years of study. The female:male sex ratio of 2210 FI beetles was 1 :0.94, with a slight but significant bias in females early in the emergence period. Although significantly more FI beetles emerged from some highly organic soils than from some mineral soils in both years, inorganic, organic and moisture factors of the test sites did not correlate consistently with the emergence of FI beetles in time or numbers. FI emergence from mineral soils was never significantly greater than that from highly organic soils. This work indicates that the economic injury level derived from studies of PI beetles in highly organic soils could be applied to other soil types with minimal risk to potato crops

Mortality and infection of wireworm, Agriotes obscurus [Coleoptera: Elateridae], with inundative field applications of Metarhizium anisopliae

In an attempt to cause fatal infection of wireworm Agriotes obscurus [Coleoptera: Elateridae], Metarhizium anisopliae was applied in the field as factorial combinations of conidia formulated as granules at 3.68 g granules or 1.25 x 1010 cfu per 196 cm2 (6.38 x 107 conidia cm-2), as conidia mixed with soil at 1.26 x 1010 cfu per 2.986 cm3 soil (4.22 x 106 conidia cm-3 soil), and as conidia-coated wheat seed (100 wheat seeds or 4.16 x 109 cfu per 196 cm2 = 2.12 x 107 conidia cm-2). The treatments resulted in a significantly greater number of mycosed wireworms compared with the control over and during five sampling periods. Significant differences in total wireworm mortality and mycosed wireworms in the field occurred at any time ranging from 15 to 82 d following treatment. The treatments also caused a reduction in the number of wireworms found in the cores, implying that they had a repellent effect. Latent infection of wireworms became apparent after living wireworms from the field treatments died following incubation under laboratory conditions, in numbers significantly greater than the control. This study showed that M. anisopliae can be applied in the field and infect and kill wireworms, but only at concentrations exceeding 4 x 106 conidia cm-3 with the subject isolate, wireworm species, and field conditions used in this study.Dans une tentative d'infecter mortellement le ver fil de fer Agriotes obscurus [Coleoptera: Elateridae], le Metarhizium anisopliae a été appliqué au champ selon des combinaisons factorielles d'une formulation granulaire de conidies à 3,68 g de granules ou 1,25 x 1010 ufc par 196 cm2 (6,38 x 107 conidies cm-2), de conidies mélangées à du sol à 1,26 x 1010 ufc par 2,986 cm3 de sol (4,22 x 106 conidies cm-3 de sol) et de graines de blé enrobées de conidies (100 graines de blé ou 4,16 x 109 ufc par 196 cm2 = 2,12 x 107 conidies cm-2). Pendant cinq périodes d'échantillonnage, un nombre significativement plus grand de vers fil de fer mycosés a été observé pour les traitements comparativement au témoin. Des différences significatives en termes de mortalité totale des vers fil de fer et de vers fil de fer mycosés au champ sont apparues à toutes les périodes, variant de 15 à 82 j après le traitement. Les traitements ont aussi réduit le nombre de vers fil de fer trouvés dans le cylindre central, ce qui indique qu'ils ont eu un effet répulsif. L'infection latente des vers fil de fer s'est manifestée lorsque des spécimens vivants provenant des traitements au champ sont morts après incubation en laboratoire, en nombres significativement plus élevés que ceux provenant du témoin. Les résultats démontrent que le M. anisopliae peut être utilisé au champ et peut infecter et tuer les vers fil de fer, mais seulement à des concentrations excédant 4 x 106 conidies cm-3 en utilisant l'isolat, le ver fil de fer, ainsi que les conditions décrites dans la présente étude

Moisture tempers impairment of adult Otiorhynchus sulcatus (Coleoptera: Curculionidae) climbing ability by fluoropolymer, talc dust, and lithium grease

As part of a project to develop tools for the physical exclusion of flightless root weevils, adult black vine weevils (BVW), Otiorhynchus sulcatus (F.), were placed in open enclosures with smooth walls of glass, plastic or aluminum to test their ability to escape by climbing. Enclosure walls were left untreated or were treated with substances known to reduce insect climbing ability: fluoropolymer, powdered talc and lithium grease. No BVW escapes were observed under dry conditions, but all treatments allowed some escapes under wet conditions, suggesting that moisture helps BVW adults scale treated surfaces. The results help explain the ability of root weevils to overcome physical barriers under field conditions