BIOLOGICAL CONTROL OF THE ALFALFA WEEVIL HYPERA POSTICA (COLEOPTERA: CURCULIONIDAE) IN NEW YORK

1971 ◽  
Vol 103 (12) ◽  
pp. 1653-1658 ◽  
Author(s):  
R. Larry Richardson ◽  
Dean E. Nelson ◽  
Alan C. York ◽  
George G. Gyrisco

AbstractTwo hymenopterous parasites Bathyplectes curculionis (Thomson) and Tetrastichus incertus (Ratzeburg) parasitized 16.5% of their principal host the alfalfa weevil Hypera postica (Gyllenhal) in 1970. A total of 2703 parasites was reared and released in localities where their activity was reported low or non-existent prior to this study. Maximum parasitism by T. incertus and B. curculionis occurred later than periods of peak weevil larvae activity; however, T. incertus emerged earlier in several areas possibly as a natural adjustment of its life cycle, and B. curculionis persisted in multiple non-diapausing generations until late fall. The braconid parasite Microtonus aethiops (Nees) shows promise in becoming a very effective control agent through its ability to prevent weevil oviposition now that it is rapidly dispersing throughout New York. Having parasites established statewide through both releases and natural dispersal has lowered weevil populations below critical levels, and will increase parasite effectiveness in dealing with future alfalfa weevil generations.

2018 ◽  
Vol 150 (2) ◽  
pp. 274-277 ◽  
Author(s):  
Tatyana A. Rand ◽  
Makenzie Pellissier ◽  
Randa Jabbour ◽  
Jonathan G. Lundgren ◽  
Debra K. Waters

AbstractThe alfalfa weevil (Hypera postica (Gyllenhal); Coleoptera: Curculionidae), is a destructive pest of alfalfa (Medicago sativa Linnaeus; Fabaceae) worldwide. The biological control parasitoid, Microctonus aethiopoides Loan (Hymenoptera: Braconidae), was successfully introduced, and considered highly effective, in the eastern and mid-western United States of America. Redistribution efforts carried out throughout the 1980s reported initial establishment in the northern Great Plains, however follow-up studies to assess long-term persistence and efficacy are lacking. We resurveyed the counties in which M. aethiopoides had been initially recovered following redistribution in Montana (Flathead and Petroleum counties), Wyoming (Platte County), and South Dakota (Brookings County), to gauge whether this species has become permanently established and, if so, assess levels of parasitism in the field. We collected adult weevils from five fields in each county, and reared them in the laboratory to assess parasitism. Despite rearing more than 1000 weevils, no parasitoids were recovered from any of the locations sampled in our study, suggesting a widespread failure of M. aethiopoides to persist in the region. Thus, M. aethiopoides does not currently appear to be an important biological control agent of alfalfa weevil in the northern Great Plains. More intensive surveys will be required to assess the extent of the distributional limits of this species throughout the region.


1991 ◽  
Vol 123 (1) ◽  
pp. 197-203 ◽  
Author(s):  
Christopher M. Maund ◽  
T.H. Hsiao

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.


1964 ◽  
Vol 54 (4) ◽  
pp. 797-803 ◽  
Author(s):  
Jean M. Taylor

A description is given of the life-cycle in Britain of Theocolax formiciformis Westw. (Pteromalidae), a parasite of Anobium punctatum (Deg.) (Anobiidae). Adults emerge from infested wood in large numbers from April to June. Eggs are laid through the wood surface and use was made of this habit as a means of rearing this parasite under observation in the laboratory. Anobium larvae were placed individually in channels gouged in the surface of 3-inch squares of plywood. They were covered with tracing paper and the parasites were caged on this by means of a glass ring covered with a glass plate. Development from egg to adult at 22 and 25°C., and 75 per cent, relative humidity, averaged about five and six weeks, respectively, compared with 12 weeks outdoors in summer. The number of progeny per female was highest (approximately five) at 22°C., at which the ratio of males to females was 1:3. Only about one per cent, of the adults reared were winged. The use of Theocolax as a biological-control agent is not considered practical.


2005 ◽  
Vol 137 (4) ◽  
pp. 488-491
Author(s):  
Qodrat Sabahi ◽  
Khalil Talebi

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).


1995 ◽  
Vol 30 (4) ◽  
pp. 481-488 ◽  
Author(s):  
T. C. Elden

Alfalfa weevil, Hypera postica (Gyllenhal), adults reared as larvae in the laboratory under an 8-h photophase were subjected to three storage conditions and two photoperiods to determine their effects on female reproductive diapause and fecundity. Contrary to previous reports, weevils reared in the laboratory as larvae and adults under a short-day photoperiod remained in a partial reproductive diapause. Newly-emerged weevil adults subjected to a 5-wk dormant period followed by an 8-h photophase had a rate of oviposition nearly twice that of adults reared under an 8-h photophase without a dormant period. Adults reared under a 15-h photophase after the dormant period also remained in a partial reproductive diapause. Results demonstrate that alfalfa weevil reproductive diapause is influenced by dormancy (an inactive state) and photoperiod. This is the first report of an efficient method to break reproductive diapause in the alfalfa weevil which will enable continuous production of nondiapausing laboratory-reared weevils for research and mass production of predators and parasites for biological control.


2004 ◽  
Vol 94 (2) ◽  
pp. 159-167 ◽  
Author(s):  
S. Jess ◽  
J.F.W. Bingham

AbstractIn small-scale experiments, the predatory mites, Hypoaspis aculeifer (Canestrini) and H. miles Berlese, applied at 700 mites m−2, and the entomopathogenic nematode, Steinernema feltiae (Filipjev) applied at 3 × 10−6 nematodes m−2 controlled sciarids and phorids in mushroom compost and casing substrates. For both mite species, earliest application to the growing substrate following sciarid infestation reduced sciarid emergence. In contrast, later application of each biological control agent provided more effective control of phorid emergence. The behaviour of adult mites suggested that H. aculeifer were more positively geotactic than H. miles although both species could penetrate compost and casing substrates to a depth of 2–12 cm. A majority of S. feltiae nematodes resided at a depth of 2–4 cm in both substrate types. Independent application of H. aculeifer provided more comprehensive control of sciarids and phorids than the other biological agents studied, owing to its better dispersal within compost and casing, and ability to attack larvae of differing ages.


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