Download the Free Unbound MEDLINE PubMed App to your smartphone or tablet.
Available for iPhone, iPad, iPod touch, and Android.
J Econ Entomol [journal]
- Effects of short photoperiod on codling moth diapause and survival. [Journal Article, Research Support, Non-U.S. Gov't]
- J Econ Entomol 2013 Feb; 106(1):520-3.
The potential presence of codling moth, Cydia pomonella L., in apples shipped to countries within the 30th latitudes has raised concerns that this pest could establish and spread in these countries. Previous research demonstrated that codling moth in apples handled under simulated commercial cold storage conditions and held under short day lengths could not break diapause and emerge in sufficient numbers to establish a minimum viable population. This study expands the in-fruit work by examining the ability of codling moth to establish a laboratory population under a short photoperiod of 12:12 (L:D) h, as compared with a long photoperiod of 16:8 (L:D) h. Codling moth larvae were collected from field infested fruits in 2010 and 2011. Moths were collected from the infested fruits and separated into two groups representing the two daylength conditions. In total, 1,004 larvae were monitored for adult emergence and ability to generate a subsequent population. Larvae held under the photoperiod of 12:12 (L:D) h generated only one moth in the 2 yr period, whereas larvae held under the photoperiod of 16:8 (L:D) h generated 186 females and 179 males, that sustained subsequent generations on artificial diet under laboratory conditions. These results indicate that under controlled environmental conditions, codling moth cannot complete diapause and emerge in sufficient numbers to sustain a viable population when held under a short photoperiod.
- Evaluation of repellency of some Chinese medicinal herbs essential oils against Liposcelis bostrychophila (Psocoptera: Liposcelidae) and Tribolium castaneum (Coleoptera: Tenebrionidae). [Evaluation Studies, Journal Article, Research Support, Non-U.S. Gov't]
- J Econ Entomol 2013 Feb; 106(1):513-9.
The screening for repellency against the booklouse, Liposcelis bostrychophila (Badonnel), and the red flour beetle, Tribolium castaneum (Herbst), from 14 Chinese medicinal herbs showed that the essential oils of Curcuma longa L., Epimedium pubescens Maximouwicz, Lindera aggregate (Sims) Kostermans, Nardostachys chinensis Battandier, Schizonepeta tenuifolia Briquet, Zanthoxylum schinifolium Sieber et Zuccarini, and Z. officinale Roscoe exhibited strong repellency against L. bostrychophila and T. castaneum. A total of 35 components of the essential oil of E. pubescens were identified by gas chromatography and gas chromatography-mass spectrometry. Beta-Eudesmol (14.89%), alpha-pinene (13.38%), borneol (9.56%), (R)-carvone (7.89%), and menthol (7.45%) were the main components of the essential oil of E. pubescens. From the essential oil of E. pubescens, four monoterpenoids and one sesquiterpenoid were isolated by bioassay-guided fractionation. The compounds were identified alpha-pinene, borneol, menthol, carvone, and beta-eudesmol. (R) -carvone, menthol, borneol, and beta-eudesmol were strongly repellent against L. bostrychophila at concentration of 8.5 nl/cm2 after 2 h exposure whereas alpha-pinene exhibited moderate repellency. (R)-carvone exhibited stronger repellency against the booklouse than the positive control, N, N-diethyl-3-methylbenzamide (DEET). Moreover, (R)-carvone also possessed stronger repellency against T. castaneum than DEET. The other four constituents, menthol, borneol, and beta-eudesmol also showed repellency against the red flour beetles but weaker than DEET at lower concentrations.
- Tribolium castaneum (Coleoptera: Tenebrionidae) associated with rice mills: fumigation efficacy and population rebound. [Journal Article, Research Support, U.S. Gov't, Non-P.H.S.]
- J Econ Entomol 2013 Feb; 106(1):499-512.
The red flourbeetle, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae), is the most important stored-product insect pest infesting rice (Oryza sativa L.) mills in the United States. Due to the phasing out of methyl bromide in accordance with the 1987 Montreal Protocol, the efficacy of alternative fumigants in controlling flour beetles in mill structures must be evaluated. Long-term trapping data sets (2-6 yr) of T. castaneum in and around seven rice mills were analyzed to assess the efficacy of sulfuryl fluoride fumigation (n = 25). Fumigation efficacy was evaluated as the percentage reduction in mean trap captures of adults and proportion of traps capturing at least one adult beetle. Beetle trap captures fluctuated seasonally, with increased captures during the warmer months, June-September, that dropped off during the cooler months, October-March. Fumigations resulted in a 66 +/- 6% (mean +/- SE) reduction in mean trap captures within mills and a 52 +/- 6% reduction in the proportion of traps capturing at least one adult beetle. Lengths of time for captures to reach prefumigation levels, or rebound rates, were variable, and adult capture levels inside were most influenced by seasonal temperature changes. Temperatures inside mills followed those outside the mill closely, and a significant positive relationship between outside temperatures and trap captures was observed. Inside and outside trap captures exhibited a significant, positive relationship, but fumigations consistently led to reductions in beetle captures outside of mills, highlighting the interconnectedness of populations located inside and outside mill structures.
- Weight loss and germination failure caused by psocids in different wheat varieties. [Journal Article, Research Support, Non-U.S. Gov't]
- J Econ Entomol 2013 Feb; 106(1):491-8.
We investigated weight loss caused by Liposcelis entomophila (Enderlein) feeding in damaged (cracked) and intact kernels of 'Jagger' variety of hard red winter wheat over a 90-d period at 30 +/- 1 degrees C and 75 +/- 5% relative humidity. L. entomophila caused 8.5% weight loss in damaged wheat kernels, which was significantly greater than the weight loss found in intact wheat kernels (0.2%). We also evaluated the suitability of six wheat varieties commonly grown in Oklahoma, namely, Jagger, 'Endurance,' 'Overley,' 'Jagalene,' 'OK Bullet,' and 'Deliver' to support populations of four psocid species, namely, Liposcelis bostrychophila Badonnel, L. decolor (Pearman), L. entomophila, and L. paeta Pearman over a 30-d period. The greatest population increase was observed in L. bostrychophila followed by L. paeta. Subsequently, weight loss of damaged and intact wheat kernels and germination of intact kernels infested by L. paeta over a 45-d period were assessed in OK Bullet variety. L. paeta caused weight loss of 3.3% in damaged kernels, which was significantly greater than the weight loss found in intact kernels (0.4%). Based on our data, 40% of infested intact kernels failed to germinate after 45 d of infestation by L. paeta, but this decreased to 32% when adjusted using germination failure of uninfested kernels. Our data show that psocid infestations do not only cause considerable loss in weight of wheat, but also result in significant germination failure. These data call for the formulation of effective integrated psocid management strategies for stored wheat to mitigate the negative impacts of psocid pests.
- Pheromone-based monitoring of Pseudococcus maritimus (Hemiptera: Pseudococcidae) populations in concord grape vineyards. [Journal Article, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, Non-P.H.S.]
- J Econ Entomol 2013 Feb; 106(1):482-90.
The grape mealybug, Pseudococcus maritimus (Ehrhorn), is the dominant mealybug in Washington's Concord grape vineyards (Vitis labrusca L.). It is a direct pest of fruit clusters and a vector of grapevine leafroll-associated viruses. Using traps baited with the sex pheromone of Ps. maritimus, we determined the optimal trap density for monitoring Ps. maritimus, with the goal of providing a more rapid monitoring method for Ps. maritimus than visual surveys. Varying densities of pheromone-baited traps (one, four, and eight traps per 12.14 ha) were deployed in Concord vineyards to monitor Ps. maritimus seasonal phenology in 2010 and 2011. In both years, flights of adult males were detected in early May and captures peaked twice per season in mid-June and mid-August, indicating two generations each year. Trap data were analyzed using Taylor's Power Law, Iwao's patchiness regression, and the K parameter of the negative binomial model to determine optimal sample size. The formula using the K parameter provided the lowest required sample size, showing that four to eight traps per 12.14 ha were needed to provide 30% sampling precision efficiency throughout the entire season. Fewer traps were needed during flight peaks when trap capture numbers were great. Only one pheromone-baited trap per 12.14 ha was sufficient to provide Ps. maritimus flight phenology data to make informed management decisions. Species-specific pheromone-baited traps deployed for Planococcus ficus (Signoret), Pseudococcus longispinus (Targioni Tozzetti), and Pseudococcus viburni (Signoret) did not detect any of these species in the vineyards sampled.
- Characterization of antibiosis and antixenosis to the woolly poplar aphid (Hemiptera: Aphididae) in the bark of different poplar genotypes. [Journal Article, Research Support, Non-U.S. Gov't]
- J Econ Entomol 2013 Feb; 106(1):473-81.
The woolly poplar aphid, Phloeomyzus passerinii (Signoret) (Hemiptera: Aphididae), is a major pest of poplar plantations in the Mediterranean basin and the Near East. Aphids colonize poplar trunks and feed upon the cortical parenchyma. Despite the economic importance of poplar, little is known about the mechanisms involved in poplar resistance to this pest. However, Populus x canadensis Moench genotypes show various levels of resistance to P. passerinii. This study has investigated the type of poplar resistance (antibiosis or antixenosis) by assessing aphid settlement, physiology (survival, development, and reproduction), and stylet penetration behavior (electrical penetration graph) on three P. x canadensis genotypes; '1214' (susceptible), 'Brenta' (resistant), and '145/51' (intermediate). Because settlement was reduced, the highly resistant genotype Brenta exhibited surface antixenosis. In addition, nymphal survival was null on Brenta, and twice less adult aphid initiated a sustained intracellular phase in the cortical parenchyma of that genotype compared with the other two genotypes. Thus, Brenta also showed parenchyma-located antixenosis coupled with antibiosis characteristic. In contrast, P. passerinii had no difficulty to initiate a sustained ingestion in the cortical parenchyma of the intermediate genotype 145/51, but decreased fecundity and lower intrinsic rate of natural increase were clear expressions of antibiosis.
- DNA-based identification of spider mites: molecular evidence for cryptic species of the genus Tetranychus (Acari: Tetranychidae). [Journal Article]
- J Econ Entomol 2013 Feb; 106(1):463-72.
Spider mites are difficult to identify because they are very small and have a limited number of diagnostic characters. Most species of the spider mite genus Tetranychus in Japan are morphologically similar, differing only in the diameter of the aedeagal knob in males. Because this genus contains many important pests, the unambiguous identification of species is crucial for effective pest management and quarantine procedures. DNA-based methods could complement the morphological methods. We examined whether Tetranychus species in Japan could be identified by DNA sequences using the internal transcribed spacer region of nuclear ribosomal DNA and the cytochrome c oxidase subunit I gene of mitochondrial DNA. We determined sequences of the 13 known Tetranychus species in Japan. We could identify 10 of the 13 species in the internal transcribed spacer tree. In the cytochrome c oxidase subunit I tree, we could identify all 13 known Tetranychus species in Japan. Although Tetranychus kanzawai Kishida and T. parakanzawai Ehara were identified by DNA sequences, they were clearly separated into two monophyletic clades each, indicating that a cryptic species existed in each species.
- Molecular cloning, characterization, and mRNA expression of two Cryptochrome genes in Helicoverpa armigera (Lepidoptera: Noctuidae). [Journal Article, Research Support, Non-U.S. Gov't]
- J Econ Entomol 2013 Feb; 106(1):450-62.
Light is a major environmental signal for insect circadian. In this study, we isolated two cryptochrome (cry) genes from Helicoverpa armigera (Hübner) by reverse transcription polymerase chain reaction and RACE-PCR strategies, designated as Ha-cryl (GenBank accession GQ896502) and Ha-cry2 (GenBank accession GQ896503). Ha-CRY1 encoded a fly-like protein of 548 amino acids, while Ha-CRY2 encoded a mammal-like protein of 657 amino acids. Both of these proteins had two conserved domains: a DNA photolyase domain and a flavin adenine dinucleotide (FAD) binding seven domain, and alignment of the amino acid sequence indicated that there was a high degree of homology between the CRYs of H. armigera and other insects. Real-time polymerase chain reaction revealed that: 1) Ha-cry1 and Ha-cry2 mRNA expressions were neither organ-specific nor developmental-stage-specific. 2) Under the light-dark cycle (16:8 L:D), Ha-cry1 abundance tended to increase during the day, then decrease in the night, whereas the expression pattern of Ha-cry2 was opposite. 3) The cyclings of Ha-cry1 and Ha-cry2 expression were disturbed by constant light and darkness. Our study has significant importance for the further study of the functions of the Ha-cry genes and potential control of the cotton bollworm.
- Molecular diagnosis of populational variants of Anthonomus grandis (Coleoptera: Curculionidae) in North America. [Comparative Study, Evaluation Studies, Journal Article]
- J Econ Entomol 2013 Feb; 106(1):437-49.
The utility of the cytochrome oxidase I (COI) DNA sequence used for DNA barcoding and a Sequence Characterized Amplified Region for diagnosing boll weevil, Anthonomus grandis Boheman, variants was evaluated. Maximum likelihood analysis of COI DNA sequences from 154 weevils collected from the United States and Mexico supports previous evidence for limited gene flow between weevil populations on wild cotton and commercial cotton in northern Mexico and southern United States. The wild cotton populations represent a variant of the species called the thurberia weevil, which is not regarded as a significant pest. The 31 boll weevil COI haplotypes observed in the study form two distinct haplogroups (A and B) that are supported by five fixed nucleotide differences and a phylogenetic analysis. Although wild and commercial cotton populations are closely associated with specific haplogroups, there is not a fixed difference between the thurberia weevil variant and other populations. The Sequence Characterized Amplified Region marker generated a larger number of inconclusive results than the COI gene but also supported evidence of shared genotypes between wild and commercial cotton weevil populations. These methods provide additional markers that can assist in the identification of pest weevil populations but not definitively diagnose samples.
- Phylogenetic analysis of the alfalfa weevil complex (Coleoptera: Curculionidae) in North America. [Journal Article, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, Non-P.H.S.]
- J Econ Entomol 2013 Feb; 106(1):426-36.
The Eastern, Western, and Egyptian strains of alfalfa weevil are pests introduced to North America on three separate occasions, now they share partially overlapping geographic ranges, covering most of the continental United States. Behavior, susceptibility to parasites, and subtle morphological differences separate the strains. The difficulty in differentiating among these strains morphologically has led to the application of molecular phylogeny approaches including restriction fragment-length polymorphism characterization and sequencing of mitochondrial genes. While valuable for strain identification, this approach cannot identify interstrain hybrids because mitochondrial markers are maternally inherited. The work reported here extends previous findings by comparing over 7 Kb of sequence from two mitochondrial and four nuclear loci to increase the resolution of molecular phylogeny for these weevils. The related clover leaf weevil, also an occasional pest of alfalfa, was included in the analysis because the molecular phylogeny of this weevil has not been examined to date. Analysis of nuclear loci indicate that the clover weevil is a distinct species. Furthermore, while the three alfalfa weevil strains are separable based on mitochondrial sequence data they cannot be separated using nuclearloci suggesting that they are all recently diverged members of the same species. These data refine the relationships among these strains and may find application in design of better control strategies.