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Structure elucidation of some insect pheromones : a contribution to the development of selective pest control agents
No full textThe use of pheromones is one of the methods currently being investigated intensively as an alternative method of insect control. The various ways in which pheromones might be used in insect control programmes are briefly discussed in Chapter 1.Chapter 2 gives a detailed description of the isolation and identification of the sex pheromone of the American cockroach, Periplaneta americana. The various techniques that have been used for the structure elucidation are described.The sex pheromone of P. americana contains two major components (periplanone-A and periplanone-B), as well as minute amounts of another four.Periplanone-B could be identified as (1 Z, 5 E)-1,10(14)-diepoxy- 4(15), 5-germacradiene-9-one. Periplanone-A proved to be very unstable, isomerizing to a biologically inactive compound. The instability of the compound rendered a complete structure elucidation impossible.The four minor compounds could not be collected in sufficient amounts to carry out a complete structure elucidation.Of the compounds reported to mimic the natural pheromone, only germacrene-D was found to do so. However, its threshold is very much higher than that of the natural pheromone. The same holds for the other reported mimics, even they do elicit electroantennogram responses. Regardless of concentration, none of the mimics elicit responses as marked as the natural pheromone.Apart from causing sexual excitation, periplanone-B also can attract males of P. americana.The isolation, identification and field evaluation of the sex pheromone of the leafroller moth, Archips podana, is described in Chapter 3. The pheromone consists of a mixture of equal amounts of cis -11-tetradecenyl acetate and trans -11-tetradecenyl acetate. Although the individual compounds are not attractive in field experiments, a 1:1 mixture of the two is capable of attracting many males of this species.Investigation of the sex pheromone of the false codling moth, Cryptophlebia leucotreta (Chapters 4 and 5) revealed that the pheromone is a mixture of equal amounts of cis -8-dodecenyl acetate and trans -8-dodecenyl acetate. This finding contradicts other reports which state that the pheromone of this insect is trans -7-dodecenyl acetate. Mixtures of cis -8- and trans -8-dodecenyl acetate in various ratios proved to be very attractive to males of this species.In Chapter 6 the isolation, identification and field evaluation of the sex pheromone of the potato tuberworm moth, Phthorimaea operculella, is described. The sex pheromone of this moth is a mixture of about equal amounts of trans -4, cis -7-tridecadienyl acetate and trans -4, cis -7, cis -10-tridecatrienyl acetate. These findings were confirmed by synthesis and by trapping experiments in the field
Codling moth granulovirus: Variations in the susceptibility of local codling moth populations
No full textThis study is part of a BMELV (German Federal Ministry for, Food, Agriculture and Consumer Protection) project for prevention of codling moth damage by long-term population control in large areas. Specimens from local codling moth populations were collected in fall 2003 from three different orchards in the South of Germany; two of them having been treated with granulovirus of codling moth (CpGV Madex 2 and/or Gran-upom) over many years (Lake Constance II and South Baden) and one since two years (Lake Constance I). In autumn 2004, specimens from populations in four other orchards with serious CM problems were col-lected to investigate whether more populations were involved in that region. Furthermore, the population Lake Constance I and South Baden were tested again. During the season, the location South Baden was almost weekly treated with 100 ml/ha of Madex 2 to test whether the level of susceptibility would change after such heavy treatments.
The susceptibility of the offsprings of the overwintering generation to CpGV was investigated in the spring of the following year in bioassays on artificial diet and compared to a laboratory strain of the codling moth. The results indicated significant differences in sensitivity to the virus between the local codling moth populations. The LC50-values showed that in 2004, South Baden and Lake Constance II were more than thousand fold less susceptible than the populations Lake Constance I and the laboratory strain. The results from the bio-assays in 2005 confirmed the low susceptibility of South Baden and of the new locations in Saarland and from an orchard 100 km away from South Baden. The population Lake Constance I, on the other hand, maintained its high sensitivity to the virus. The slope of the dose-mortality-regression lines of the unsuscep-tible populations was significantly lower than those of the susceptible ones, including that of the laboratory strain. This indicates a high inhomogeneity in the individual response of the unsusceptible larvae against the virus. Actually, the problem of reduced sensitivity to the virus seems to be limited to a few orchards in Germany, the majority of orchards being not affected
Mass rearing codling moths: improvements and modifications
No full textCurrent diet, oviposition cages, rearing containers, diapause induction and adult handling are described for a rearing colony of codling moth, Cydia pomonella (L.), maintained at the USDA-ARS facility in Wapato, WA , USA, for over 40 years for use in field, laboratory and postharvest research. Previous studies have found codling moth production to approach maximum efficiency at a density of one larva per 4.8 ml of diet. Since 2002, the current YARL rearing program has produced an average of 1 adult per 4.5 ml diet
Laboratory and field experiments towards the development of an attract and kill strategy for the control of the codling moth, Cydia pomonella
No full textA viscous formulation based on castor oil containing the pyrethroid insecticide cyfluthrin and E8, E10-dodecadienol, the main component of the codling moth sex pheromone, (Cydia pomonella L.: Tortricidae, Olethreutinae) was developed. The insecticidal performance of the formulation was evaluated in the laboratory using a tarsal-contact bioassay. The pheromone dosage required to attract male moths to the formulation was determined in behavioural tests performed in a wind tunnel. The efficacy of formulations applied to seedlings of the host plant was further investigated in glasshouse experiments conducted with male moths in small wire-gauze cages. The laboratory tests resulted in a formulation for preliminary field trials containing 4% cyfluthrin and 0.1% pheromone. During the 1995 growing season, experiments were conducted in apple orchards at three locations in Germany. The formulation was first applied to the bark of apple trees (Malus domestica) in mid May and then again in late July. A good level of control, comparable with a spray treatment using the insect growth regulator Alsystin was achieved. The potential of the attract and kill strategy, combining selective attraction of a pest species with the efficacy associated with a pyrethroid insecticide treatment, as a means of controlling the codling moth in commercial apple growing, is discussed
Comparing Integrated Pest Management and Protectant Strategies for Control of Apple Scab and Codling Moth in an Iowa Apple Orchard
No full textIntegrated peat management (IPM) strategies for control of apple scab and codling moth (Cydia pomonolla) were compared with a traditional protestant spray program in an Iowa apple orchard over a 3-year period. IPM tactics for scab included a postinfection spray program and an integrated, reduced-spray program based on the use of demethylation inhibitor fungicides. Codling moth spray timing was determined by pheromone-trap captures and degree-day models. The IPM tactics resulted in an average of three fewer fungicide sprays and two fewer insecticide sprays than the protestant program. Neither yield, incidence of fruit scab, nor incidence of codling moth injury on fruit was significantly different among the two IPM treatments and the protestant treatment. A no-fungicide treatment had significantly lower yield and greater scab incidence than the other treatments. A partial budget analysis indicated that the treatment using the postinfection strategy was more costly per acre than the protectant program for orchardsacres, about equivalent in cost for 20 acres, but leas costly for 40 acres. A treatment incorporating the integrated, reduced-spray strategy was less costly than either postinfection or protestant strategies at orchard sizes from 5 to 40 acres. Return (total revenue - cost for control of primary scab and codling moth) per acre for the IPM strategies was somewhat lower than for the protestant program.This article is published as Gleason, Mark L., M. K. Ali, Paul A. Domoto, D. R. Lewis, and M. D. Duffy. "Comparing integrated pest management and protectant strategies for control of apple scab and codling moth in an Iowa apple orchard." HortTechnology 4, no. 2 (1994): 136-141. Posted with permission.</p
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Female codling moth, Cydia pomonella (Lepidoptera: tortricidae), antennal responses to serial dilutions of apple volatile chemicals
No full textVolatile chemicals from apples collected during each of the two codling moth, Cydia pomonella, flights in central Washington were analyzed using gas chromatography coupled with electroantennal detection (GC-EAD) using serially diluted samples. More concentrated immature apple volatile chemical collections elicited significantly more antennal responses than less concentrated volatile chemical collections. Antennal responses of wild codling moths were compared to laboratory-reared moths at one concentration with no significant difference found. Four immature apple volatile chemicals elicited an antennal response at the lowest concentration and three of these were identified. These chemicals are: (Z)-3-hexenol, (d)-linalool, and (E,E)-[alpha]-farnesene. The fourth chemical eluted with the solvent peak during analysis preventing structural determination and indicating low boiling point and low molecular weight. These chemicals are of interest for understanding how codling moths use kairomones to find and select host for oviposition and, ultimately, developing attractants for female codling moths
Characterisation of novel CrleGV isolates for false codling moth control-lessons learnt from codling moth resistance to CpGV. Characterisation of novel CrleGV isolates for false codling moth control-lessons learnt from codling moth resistance to CpGV
No full textRecently some codling moth, Cydia pomonella, populations in Europe developed resistance to CpGV. In order to prepare for the possibility of a similar occurrence with the false codling moth, Thaumatotibia leucotreta, in South Africa, a search was conducted for novel CrleGV isolates. Through overcrowding, outbreaks of novel isolates were recorded from laboratory populations of five geographically distinct host populations. The genetic novelty of these and two commercially available isolates was confirmed through restriction enzyme analysis and sequence analysis of the granulin and egt genes. Phylogenetic analysis showed the existence of two CrleGV-SA genome types. Significant differences in virulence were also shown between certain isolates against certain host populations
Madex Plus and Madex I12 overcome Virus Resistance of Codling Moth
No full textOver the past three years, codling moth populations with resistance to the Mexican isolate
of Cydia pomonella Granulovirus (CpGV) have been found in Germany, France, Italy,
Switzerland and the Netherlands. Andermatt Biocontrol has tested two new virus isolates
(Madex Plus and Madex I12) which can overcome CpGV-resistance, and compared them
in the field. Both isolates proved effective against Mexican isolate resistant codling moth
populations, in several locations. In Switzerland, Madex Plus has been already approved
for use
MeSH term explosion and author rank improve expert recommendations
No full textInformation overload is an often-cited phenomenon that reduces the productivity, efficiency and efficacy of scientists. One challenge for scientists is to find appropriate collaborators in their research. The literature describes various solutions to the problem of expertise location, but most current approaches do not appear to be very suitable for expert recommendations in biomedical research. In this study, we present the development and initial evaluation of a vector space model-based algorithm to calculate researcher similarity using four inputs: 1) MeSH terms of publications; 2) MeSH terms and author rank; 3) exploded MeSH terms; and 4) exploded MeSH terms and author rank. We developed and evaluated the algorithm using a data set of 17,525 authors and their 22,542 papers. On average, our algorithms correctly predicted 2.5 of the top 5/10 coauthors of individual scientists. Exploded MeSH and author rank outperformed all other algorithms in accuracy, followed closely by MeSH and author rank. Our results show that the accuracy of MeSH term-based matching can be enhanced with other metadata such as author rank
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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