Evaluation and Calibration of Sampling Methods Used to Estimate Abundance of Alfalfa Weevil Larvae (Coleoptera: Curculionidae)

1992 ◽  
Vol 27 (3) ◽  
pp. 202-208 ◽  
Author(s):  
John M. Luna ◽  
F. William Ravlin
Keyword(s):  
Sampling Methods ◽  
Fourth Instar ◽  
Larval Abundance ◽  
Alfalfa Weevil ◽  
Hypera Postica ◽  
Accuracy And Precision ◽  
Coefficients Of Variation ◽  
Plastic Bag ◽  
Calibration Equations ◽  
Sweep Net

Three sampling methods for estimating abundance of alfalfa weevil larvae (Hypera postica Gyllenhal) were evaluated for both accuracy and precision. A plastic bag/Tullgren funnel method collected significantly fewer second, third, fourth instar and total larvae than did the bucket-shake method. Calibration equations were developed to convert intensity estimates (alfalfa weevil larvae per alfalfa stem) obtained from the plastic bag/Tullgren funnel method to bucket-shake estimates. Sweep-net sampling produced significantly lower coefficients of variation than both bucket-shake and plastic bag/Tullgren funnel sampling methods, however mean estimates of larval abundance obtained from sweep-net sampling could be reliably converted to bucket-shake estimates for only fourth instar larvae.

Demographic studies of Oomyzus incertus (Hymenoptera: Eulophidae), a larval parasitoid of Hypera postica (Coleoptera: Curculionidae), treated with four organophosphorous insecticides

2005 ◽  
Vol 137 (4) ◽  
pp. 488-491
Author(s):  
Qodrat Sabahi ◽  
Khalil Talebi
Keyword(s):  
Life Cycle ◽  
Medicago Sativa ◽  
Fourth Instar ◽  
Northern Iran ◽  
Alfalfa Weevil ◽  
Hypera Postica ◽  
Larval Parasitoid ◽  
Organophosphorous Insecticides

The alfalfa weevil, Hypera postica (Gyllenhal) (Coleoptera: Curculionidae), can severely damage the first cutting of alfalfa, Medicago sativa L. (Fabaceae), in much of Iran. The pest has been parasitized by several parasitoids including Oomyzus incertus (Ratzeburg) (Hymenoptera: Eulophidae), a gregarious larval endoparasitoid. This wasp can parasitize up to 30% of weevil larvae in alfalfa fields in northern Iran. It produces three to four generations per year, and the female prefers the fourth instar of the host for oviposition. Each female lays 2 to 22 eggs per host, which hatch within 47–60 h. The life cycle is completed in about 2 weeks, upon pupation inside the host. This species is predominantly present during the summer months in alfalfa fields (Streams and Fuester 1967).

scholarly journals Management of the Egyptian alfalfa weevil, Hypera brunneipennis (Boheman) (Coleoptera: Curculionidae), in the alfalfa, Medicago sativa L., using the entomopathogenic fungus, Beauveria bassiana (Balsamo) Vuillemin

2019 ◽  
Vol 29 (1) ◽  
Author(s):  
Monir M. M. El Husseini
Keyword(s):  
Medicago Sativa ◽  
Beauveria Bassiana ◽  
Entomopathogenic Fungus ◽  
Larval Population ◽  
Alfalfa Weevil ◽  
Alfalfa Field ◽  
Medicago Sativa L ◽  
Hypera Brunneipennis ◽  
Fungus Beauveria Bassiana ◽  
Sweep Net

AbstractLarval and adult populations of the Egyptian alfalfa weevil (EAW) Hypera brunneipennis (Boheman) (Coleoptera: Curculionidae) was monitored after application of the entomopathogenic fungus Beauveria bassiana in the alfalfa field (Medicago sativa L.) in two successive seasons 2014/2015 and 2015/2016. The second and last generation of the weevil on April 10, 2016, was controlled by only one application with the conidiospores of the entomopathogenic fungus B. bassiana (3 × 108 spores/ml). Accordingly, the larval population decreased from 16.07 ± 1.09 in season 2015/2016 to 7.37 ± 0.05 individuals/50 sweep net double strokes in season 2016/2017. Also, the adult weevil’s population decreased from 5.66 ± 0.8 to 2.55 ± 0.6 individuals/50 sweep net double strokes in the two seasons, respectively. 39.66% mortality rate was recorded in the Hypera brunneipennis adults aestivated under loose bark of the surrounding eucalyptus trees, which received the application of B. bassiana in the field. Another application with the fungus, targeting the second generation of the pest adults in alfalfa each season, will undoubtedly lead to a further decrease in the pest population.

EFFECTS OF CARBOFURAN ON ARTHROPOD POPULATIONS AND CROP YIELD IN HAYFIELDS

1972 ◽  
Vol 104 (9) ◽  
pp. 1433-1437 ◽  
Author(s):  
C. D. Dondale
Keyword(s):  
Crop Yield ◽  
Crude Protein ◽  
Alfalfa Weevil ◽  
Hypera Postica

AbstractCarbofuran was applied to three hayfields at a rate of 0.56 kg/ha in early June. This caused significant reductions of Thysanoptera, phytophagous Coleoptera larvae (including the alfalfa weevil, Hypera postica (Gyl.)), and Cicadellidae. It caused similar reductions in Araneida and parasitoids. The differences between treated and untreated plots were no longer significant by September. Carbofuran did not significantly affect the yield of air-dried hay or of crude protein.

DIFFERENTIAL ENCAPSULATION OF TWO BATHYPLECTES PARASITOIDS AMONG ALFALFA WEEVIL STRAINS, HYPERA POSTICA (GYLLENHAL)

1991 ◽  
Vol 123 (1) ◽  
pp. 197-203 ◽  
Author(s):  
Christopher M. Maund ◽  
T.H. Hsiao
Keyword(s):  
Biological Control ◽  
Control Strategy ◽  
Laboratory Studies ◽  
Alfalfa Weevil ◽  
Hypera Postica ◽  
Biological Differences

AbstractEncapsulation of Bathyplectes curculionis (Thomson) and B. anurus (Thomson) (Hymenoptera: Ichneumonidae) was investigated by dissecting parasitized larvae of three strains of the alfalfa weevil, Hypera postica (Gyllenhal) (Coleoptera: Curculionidae). In laboratory studies, there was no encapsulation of B. curculionis in the western strain of the weevil, a significant level of encapsulation in the eastern strain of the weevil, and nearly complete encapsulation in the Egyptian strain of the weevil. The rickettsia, Wolbachia postica Hsiao and Hsiao, found only in the western strain, was not involved in encapsulation. Variation in encapsulation was due to biological differences between weevil strains. Encapsulation rates among field populations of the western and Egyptian weevils were lower than in the laboratory. Encapsulation rates of weevil populations from zones in which western and Egyptian strains overlap in southern Utah, and between eastern and western strains in Colorado, were intermediate to rates of parental strains. These results imply that B. curculionis effectiveness against the western alfalfa weevil will decline with mixing of weevil strains. Bathyplectes anurus did not evoke encapsulation and was able to develop equally well in all three weevil strains. Our findings illustrate the importance of investigating the compatibility between alfalfa weevil strains and their parasitoids in devising a sound biological control strategy.

Multiresidue Gas Chromatographic Method for Determining Organochlorine Pesticides in Poultry Fat: Collaborative Study

1984 ◽  
Vol 67 (2) ◽  
pp. 284-289 ◽  
Author(s):  
James A Ault ◽  
Tim E Spurgeon ◽  
◽  
M M Anderson ◽  
R Bowers ◽  
...  
Keyword(s):  
Chromatographic Method ◽  
Collaborative Study ◽  
Gel Permeation Chromatography ◽  
Accuracy And Precision ◽  
Coefficients Of Variation ◽  
Poultry Fat ◽  
Gel Permeation ◽  
Detector Method ◽  
Gas Chromatographic Method

Abstract A gas chromatographic electron capture detector method is described for the quantitative determination of organochlorine pesticide residues in poultry fat. The samples are rendered and cleaned up using automated gel permeation chromatography. The collaborative samples consisted of 10 fortified samples and one incurred residue sample, all in duplicate. Fortification levels ranged from 0.15 to 1.0 ppm for a-BHC, lindane, cis- and frans-chlordane, octachlor epoxide, o,p' and p,p'-DDT, p,p'-DDE, p,p'-TDE, hexachlorobenzene, heptachlor epoxide, dieldrin, endrin, methoxychlor, mirex, and toxaphene. The average recovery was 91.9% with a range of 81-102%. The ranges of coefficients of variation were: CVo = 3.39-14.79%; CVL = 0-16.6%; and CVx = 5.82-19.0%. The results indicate accuracy and precision comparable to other official methodology. The method has been adopted official first action.

Alfalfa Weevil, Hypera postica (Gyllenhal) (Coleoptera: Curculionidae)

2008 ◽  
pp. 110-110
Author(s):  
George Hangay ◽  
Severiano F. Gayubo ◽  
Marjorie A. Hoy ◽  
Marta Goula ◽  
Allen Sanborn ◽  
...  
Keyword(s):  
Alfalfa Weevil ◽  
Hypera Postica

Simplified Plate Diffusion System for Microbial Assays of Antibiotics

1987 ◽  
Vol 70 (4) ◽  
pp. 641-646
Author(s):  
Marietta Sue Brady ◽  
Stanley E Katz
Keyword(s):  
Diffusion System ◽  
Standard Curve ◽  
Single Plate ◽  
Accuracy And Precision ◽  
Coefficients Of Variation

Abstract A protocol for microbial assays of antibiotics, using the plate diffusion system, is presented. The system is based on the concept that a complete standard curve and assay unknowns can be placed on an issay plate and that 2 plates can be a complete assay with an accuracy and precision essentially equivalent to the official AOAC diffusion procedure. Four antibiotics, bacitracin, chlortetracycline, oxytetracycline, and streptomycin, were used in the design and comparison studies with the AOAC protocol. The coefficients of variation (CVs) for the AOAC design, using 10 replicates, ranged from 1.4 to 10.3% with a mean of 4.5%. The CVs for the single-plate option of the simplified design ranged from 4.3 to 9.6% with a mean of 6.6%; the CVs for the 2-plate option ranged from 2.5 to 6.8% with a mean of 43%; the CVs for the 3-plate option ranged from 1.2 to 5.0% with a mean of 3.0%.

Sign in / Sign up

Export Citation Format

Share Document