Biological control of alfalfa weevil under unstable paddy field environment in Japan

2016 ◽  
Author(s):  
Masami Takagi
Keyword(s):  
Biological Control ◽  
Paddy Field ◽  
Alfalfa Weevil ◽  
Field Environment

Assessing the role of generalist predators in the biological control of alfalfa weevil (Coleoptera: Curculionidae)

2017 ◽  
Vol 149 (4) ◽  
pp. 525-533 ◽  
Author(s):  
Tatyana A. Rand
Keyword(s):  
United States ◽  
Biological Control ◽  
Experimental Work ◽  
United States Of America ◽  
Acyrthosiphon Pisum ◽  
The United States ◽  
Generalist Predators ◽  
Alfalfa Weevil ◽  
Exclusion Experiment ◽  
Predator Exclusion

AbstractAlfalfa weevil (Coleoptera:Curculionidae) is a major pest of alfalfa throughout the United States of America. Biological control research has disproportionately focussed on introduced parasitoids. Generalist predators may also be important, but experimental work evaluating their impacts is lacking. I combined a cross-site survey with a predator exclusion experiment to identify key predators, and test for impacts on weevil survival and plant defoliation levels in Montana and North Dakota, United States of America. Spiders (Araneae) dominated the complex, followed by Nabidae (Hemiptera) and Coccinellidae (Coleoptera). None of the dominant predators showed aggregative responses to weevil (Hypera postica (Gyllenhal); Coleoptera: Curculionidae) or pea aphid (Acyrthosiphon pisum (Harris); Hemiptera: Aphididae) densities across 10 sites surveyed. However, weevil densities were positively correlated with both coccinellid and nabid densities across transects at the experimental site. Thus, predator groups traditionally associated with aphids can show strong aggregative numerical responses to alfalfa weevil larvae at smaller scales. Predator exclusion revealed no significant predator effects on larval survival or alfalfa damage. However, final densities of pea aphids were significantly higher in exclusion treatments relative to controls. The results suggest that even under conditions where predators exert significant pressure on aphids, they may still have minimal impacts on weevils. Additional experimental work is necessary to determine the broader potential of generalist predators as alfalfa weevil control agents.

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.

Effects of Dormancy and Photoperiod on Alfalfa Weevil (Coleoptera: Curculionidae) Reproductive Diapause

1995 ◽  
Vol 30 (4) ◽  
pp. 481-488 ◽  
Author(s):  
T. C. Elden
Keyword(s):  
Biological Control ◽  
Efficient Method ◽  
Mass Production ◽  
Continuous Production ◽  
Storage Conditions ◽  
Reproductive Diapause ◽  
Dormant Period ◽  
Alfalfa Weevil ◽  
Hypera Postica ◽  
Inactive State

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.

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
Keyword(s):  
New York ◽  
Biological Control ◽  
Life Cycle ◽  
Control Agent ◽  
Effective Control ◽  
Critical Levels ◽  
Alfalfa Weevil ◽  
Hypera Postica ◽  
Late Fall ◽  
Natural Dispersal

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.

Economic analysis of an areawide program for biological control of the alfalfa weevil

1995 ◽  
Vol 10 (4) ◽  
pp. 173-179 ◽  
Author(s):  
J.M. White ◽  
P.G. Allen ◽  
L.J. Moffitt ◽  
P.P. Kingsley
Keyword(s):  
Biological Control ◽  
Control Program ◽  
Economic Benefits ◽  
Cost Ratio ◽  
Biological Pest Control ◽  
Alfalfa Weevil ◽  
Benefit Cost Analysis ◽  
Benefit Cost Ratio ◽  
Livestock Products ◽  
Benefit Cost

AbstractAn areawide program for biological control of the alfalfa weevil showed expected economic benefits of $2.2 billion, expressed in present value terms. Alfalfa producers and consumers of livestock products are the main beneficiaries. The control program was highly successful, with a benefit/cost ratio of about 91. Not all areawide biological pest control programs will be as successful; a benefit-cost analysis like the one described here should be performed before areawide control is initiated to identify programs expected to provide economic benefits.

OVARY STRUCTURE AND REPRODUCTIVE BIOLOGIES OF LARVAL PARASITOIDS OF THE ALFALFA WEEVIL (COLEOPTERA: CURCULIONIDAE)

1978 ◽  
Vol 110 (5) ◽  
pp. 507-512 ◽  
Author(s):  
Robert Dowell
Keyword(s):  
Biological Control ◽  
Egg Production ◽  
Host Density ◽  
Instar Larva ◽  
Host Feeding ◽  
Reproductive Proteins ◽  
Alfalfa Weevil ◽  
Parasitic Hymenoptera ◽  
First Instar ◽  
Egg Storage

AbstractTwo manners in which parasitic Hymenoptera gather reproductive proteins are described. Hydropic species gather all protein necessary for reproduction as larvae. Only 5–10% of the material necessary to form a viable first instar larva is put into each egg; the remainder is gathered by the egg within the host. Egg storage is in the lateral oviducts, handling times are short and egg production is independent of host density. Three Bathyplectes spp. are examples of hydropic parasitoids. Anhydropic species gather some or all protein as adults, often by host feeding. All the material necessary for the formation of a viable first instar larva is stored within the egg. The eggs are held in the ovary until laid. Handling times are longer and continued egg production is dependent upon host density. Tetrastichus incertus (Ratzeburg) is an anhydropic parasitoid.Hydropic parasitoids appear best suited for biological control efforts in ephemeral situations (i.e. cotton or alfalfa). Anhydropic parasitoids appear best suited for biological control efforts in stable situations (i.e. citrus or walnuts).

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