A THERMAL SUMMATION MODEL FOR PREDICTING SEASONAL OCCURRENCE OF THE ALFALFA WEEVIL, HYPERA POSTICA (COLEOPTERA: CURCULIONIDAE), IN SOUTHERN ONTARIO

1981 ◽  
Vol 113 (7) ◽  
pp. 601-605 ◽  
Author(s):  
D. G. Harcourt
Keyword(s):  
Adult Emergence ◽  
Seasonal Occurrence ◽  
Alfalfa Weevil ◽  
Southern Ontario ◽  
Hypera Postica ◽  
Heat Units ◽  
Model Based ◽  
Significant Events

AbstractA thermal summation model based on heat units above 9°C accurately predicted peak hatch of eggs, an event critical to management of the alfalfa weevil, Hypera postica (Gyll.), in southern Ontario. The model also gave accurate predictions for maximum numbers of the larval and pupal stages, as well as other significant events such as cocooning and adult emergence.

ESTIMATION OF EGG POPULATIONS OF THE ALFALFA WEEVIL, HYPERA POSTICA (COLEOPTERA: CURCULIONIDAE)

1974 ◽  
Vol 106 (4) ◽  
pp. 337-347 ◽  
Author(s):  
D. G. Harcourt ◽  
M. K. Mukerji ◽  
J. C. Guppy
Keyword(s):  
Poisson Distribution ◽  
Alfalfa Weevil ◽  
Southern Ontario ◽  
Hypera Postica ◽  
Valid Index ◽  
Direct Counts

AbstractAs part of a detailed study of the life system of the alfalfa weevil, Hypera postica (Gyll.), in southern Ontario, two methods were developed for estimating numbers of eggs in the spring growth of alfalfa. The first is based on direct counts of the eggs, which are laid in clusters and hence, aggregated in distribution; for moderate levels of infestation (ca. 8 eggs per bouquet), estimates with acceptable precision may be obtained by taking a single 3-stem bouquet of alfalfa from 80 randomly selected ft2 (.09 m2) quadrats within a field. The second is based on counts of the oviposition punctures which are randomly dispersed and consistent with the Poisson distribution. Although slightly less accurate, this method will provide a valid index of the number of eggs with less labour; acceptable precision may be obtained by taking a single bouquet from just 32 quadrats.

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.

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).

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

EFFECT OF FIELD APPLICATIONS OF CARBOFURAN ON HYPERA POSTICA (COLEOPTERA: CURCULIONIDAE) AND ITS PARASITOIDS

1976 ◽  
Vol 108 (6) ◽  
pp. 649-654
Author(s):  
G. A. Surgeoner ◽  
C. R. Ellis
Keyword(s):  
Unit Area ◽  
Alfalfa Weevil ◽  
Hypera Postica ◽  
Percentage Parasitism

AbstractCarbofuran at 2 oz AI/acre caused a 94% reduction in 3rd- and 4th-instar larvae of alfalfa weevil. There was a 67% reduction in 1st- and 2nd-instar larvae which were protected within the buds. Carbofuran did not reduce the percentage parasitism by Bathyplectes curculionis (Thomson) although the total parasitoids that developed per unit area was less.

A Nematode Parasite of the Alfalfa Weevil (Hypera postica (Gyll.))

1960 ◽  
Vol 53 (1) ◽  
pp. 178-179 ◽  
Author(s):  
George O. Poinar ◽  
George G. Gyrisco
Keyword(s):  
Nematode Parasite ◽  
Alfalfa Weevil ◽  
Hypera Postica
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