scholarly journals Investigation into the delayed establishment of Microctonus aethiopoides in Northland

2009 ◽  
Vol 62 ◽  
pp. 414-414
Author(s):  
T.M. Eden ◽  
P.J. Gerard ◽  
J.J. Dymock ◽  
N. Ahmad
Keyword(s):  
New Zealand ◽  
High Mortality ◽  
Far North ◽  
Larval Diapause ◽  
Sitona Lepidus ◽  
Critical Photoperiod ◽  
Clover Root ◽  
Microctonus Aethiopoides ◽  
Multiple Releases ◽  
Collection Sites

The Irish strain of Microctonus aethiopoides was released in New Zealand in 2006 to help control clover root weevil (Sitona lepidus) Establishment was rapid at all release sites except in Northland where multiple releases appeared to fail until low numbers were recovered in 2008 It was hypothesised that because Northland at 35S is at sufficiently different latitude to the original collection sites near Belfast Ireland (5437N) there is a crossing of the critical photoperiod for diapause induction in the wasp larvae Replicated cage trials were undertaken to compare the prevalence of premature diapause in Northland with Waikato under natural daylength and simulated Far North midsummer photoperiod (1410 h light dark) with a 16 h photoperiod Results indicated that larval diapause inside the weevil may be initiated by the parent wasp as significantly more 1st instar larvae were present in weevils where wasps had been subjected to reducing daylength (16 h down to 14 h light) High mortality amongst singlylaid wasp larvae in the Northland summer and the absence of teratocytes usually associated with larvae indicates clover root weevil adults can defeat a singlylaid parasitoid These results may explain the reduced efficacy of the Irish wasp in Northland

scholarly journals Farmer response to minirelease strategy for the clover root weevil biocontrol agent

2010 ◽  
Vol 63 ◽  
pp. 283-283
Author(s):  
P.J. Gerard ◽  
D.J. Wilson ◽  
T.M. Eden
Keyword(s):  
New Zealand ◽  
Technology Transfer ◽  
Biocontrol Agent ◽  
Good Condition ◽  
High Demand ◽  
Dairy Farmers ◽  
Sitona Lepidus ◽  
Parasitism Rates ◽  
Clover Root ◽  
Microctonus Aethiopoides

The Irish wasp Microctonus aethiopoides was released in 2006 as a biocontrol agent for the clover root weevil Sitona lepidus a serious pest of white clover in New Zealand Following the successful and very rapid establishment of the Irish wasp there was high demand by farmers for the biocontrol Around 2000 minirelease samples were distributed directly to farmers through pastoral industry networks and field days These consisted of ten fieldcollected weevils exposed to the wasp in the laboratory at parasitism rates such that over 99 of samples contained parasitoids A random subsample of 100 recipient dairy farmers was surveyed subsequently by post with 59 responses The minireleases were well received most going to farmers that had previously experienced losses due to the weevil The mini releases were very effective in terms of getting the biocontrol to farms with 92 of insects arriving in good condition and 96 being released on the same day The farmers appeared receptive of the information provided with the samples indicating the project was successful in terms of technology transfer There was good recognition of DairyNZ with 79 showing awareness of the organisations funding enabling the biocontrol research

scholarly journals Importation to New Zealand quarantine of a candidate biological control agent of clover root weevil

2001 ◽  
Vol 54 ◽  
pp. 147-151 ◽  
Author(s):  
S.L. Goldson ◽  
C. Phillips ◽  
M.M. McNeill ◽  
J.R Proffitt ◽  
R.P. Cane
Keyword(s):  
Genetic Diversity ◽  
Biological Control ◽  
New Zealand ◽  
Biological Control Agent ◽  
Genetic Material ◽  
Control Agent ◽  
Biological Control Agents ◽  
Sitona Lepidus ◽  
Clover Root ◽  
Microctonus Aethiopoides

Several candidate biological control agents of Sitona lepidus have been identified since a search commenced in 1997 Interestingly Microctonus aethiopoides from Europe is a much more effective parasitoid of S lepidus than the M aethiopoides ecotype already established in New Zealand To assess further the suitability of the European M aethiopoides for biological control of S lepidus 1599 infected S lepidus were shipped to New Zealand quarantine during late 2000 These yielded 267 parasitoid pupae from which 204 adult parasitoids were reared This material was obtained from a wide geographical range in Europe and has been used to establish cultures in New Zealand quarantine based on genetic material from France England Norway Finland Romania Ireland Scotland Italy and Wales This contribution presents an overview of the work associated with the importation of the parasitoids and the effort now being made to maintain genetic diversity Planned research is also discussed

scholarly journals The effect of parasitism on clover root weevil flight capability

2008 ◽  
Vol 61 ◽  
pp. 31-34
Author(s):  
T.M. Eden ◽  
M. Donald ◽  
P.J. Gerard
Keyword(s):  
New Zealand ◽  
Flight Activity ◽  
Biocontrol Agents ◽  
Passive Dispersal ◽  
First Instar ◽  
Sitona Lepidus ◽  
Clover Root ◽  
Flight Muscles ◽  
Microctonus Aethiopoides

The Irish strain of Microctonus aethiopoides was released in New Zealand in 2006 to help suppress populations of the clover pest clover root weevil (Sitona lepidus) A study was undertaken to determine if this parasitoid will be passively dispersed through flight activity by parasitized hosts In the laboratory Irish M aethiopoides parasitized equally hosts with or without flight muscles and subsequent presence of parasitoid eggs or first instar larvae had no effect on the propensity for S lepidus to prepare to take flight during laboratory observations In the field significantly fewer clover root weevil with flight muscles were found to be parasitized compared to those without flight muscles and those that were parasitized contained predominantly eggs and first instar larvae The results were compared with other Microctonus biocontrol agents released in New Zealand and it was concluded that passive dispersal should play a major role in dispersing Irish M aethiopoides in New Zealand especially in warm dry summers

scholarly journals Distribution of the clover root weevil biocontrol agent in the North Island of New Zealand

2008 ◽  
Vol 61 ◽  
pp. 24-30 ◽  
Author(s):  
P.J. Gerard ◽  
T.M. Eden ◽  
D.J. Wilson ◽  
G. Burch
Keyword(s):  
New Zealand ◽  
Biocontrol Agent ◽  
Point Sources ◽  
The North ◽  
Sitona Lepidus ◽  
Clover Root ◽  
Successful Establishment ◽  
Set Up ◽  
Microctonus Aethiopoides ◽  
Training And Support

The Irish wasp Microctonus aethiopoides was released in 2006 as a biocontrol agent for the clover root weevil Sitona lepidus a serious pest of white clover in New Zealand Following successful establishment two strategies were implemented to accelerate the widespread establishment of the parasitoid throughout the North Island The first approach was the establishment of regional nursery sites that act as point sources for natural and assisted dispersal With the assistance of Regional Councils and major landowners these were set up at sites favourable to the wasp and local people were provided the training and support to undertake collections and distribution of parasitized weevils Secondly samples of parasitized weevils were distributed for release directly to farmers through pastoral industry networks and events Initial results indicate that while the parasitoid established rapidly at Taranaki and Waikato nursery sites as anticipated it has failed to establish in Northland in two successive seasons

scholarly journals Allozyme variation between European and New Zealand populations of Microctonus aethiopoides

2003 ◽  
Vol 56 ◽  
pp. 133-137 ◽  
Author(s):  
I.I. Iline ◽  
C.B. Phillips
Keyword(s):  
Genetic Variation ◽  
Gene Flow ◽  
New Zealand ◽  
Allozyme Variation ◽  
Enzyme Electrophoresis ◽  
Preliminary Assessment ◽  
Sitona Lepidus ◽  
Clover Root ◽  
Microctonus Aethiopoides ◽  
European Populations

The parasitoid Microctonus aethiopoides Loan (Hymenoptera Braconidae) was introduced to New Zealand in 1982 for control of Sitona weevil Sitona discoideus Gyllenhal (Coleoptera Circulionidae) a pest of lucerne Unfortunately New Zealand populations of M aethiopoides do not parasitise clover root weevil Sitona lepidus Gyllenhal but European populations do Several PCRbased methods have demonstrated the existence of genetic variation between and amongst European and New Zealand populations of M aethiopoides However enzyme electrophoresis methods have the potential to provide less expensive population markers and these could also prove more useful than PCRbased markers for studying gene flow between European and New Zealand M aethiopoides populations This paper reports a preliminary assessment of allozyme variation between European and New Zealand M aethiopoides Nine enzymes and general proteins were assayed but the only variation was observed at esterase (EST) with two alleles present at each of two loci

scholarly journals Rationale for release of the Irish strain of Microctonus aethiopoides for biocontrol of clover root weevil

2006 ◽  
Vol 59 ◽  
pp. 285-289 ◽  
Author(s):  
P.J. Gerard ◽  
M.R. McNeill ◽  
B.I.P. Barratt ◽  
S.A. Whiteman
Keyword(s):  
New Zealand ◽  
Host Range ◽  
Biocontrol Agent ◽  
Hazardous Substances ◽  
Sitona Lepidus ◽  
Clover Root ◽  
Microctonus Aethiopoides ◽  
Poor Efficacy

A European biotype of Microctonus aethiopoides was identified as the best candidate biocontrol agent for Sitona lepidus a serious New Zealand pasture pest A Moroccan biotype was already present throughout the country and hence there was no requirement to obtain Hazardous Substances and New Organisms (HSNO) Act approval to release new biotypes However as research had shown mating between the two biotypes produced hybrids with poor efficacy against target hosts and that the Moroccan biotype attacked several native weevil genera serious reservations were held about introducing the European biotype Concerns were overcome with the identification of a parthenogenetic strain of European M aethiopoides from Ireland which has little risk of hybridisation and a narrower host range than the Moroccan biotype Following regulation of M aethiopoides as a risk species this strain was considered to be a new organism Approval was sought and gained under the HSNO Act to release the strain

scholarly journals Initial establishment of the irish strain of Microctonus aethiopoides in New Zealand

2007 ◽  
Vol 60 ◽  
pp. 203-208 ◽  
Author(s):  
P.J. Gerard ◽  
T.M. Eden ◽  
S. Hardwick ◽  
C.F. Mercer ◽  
M.W.A. Slay ◽  
...  
Keyword(s):  
New Zealand ◽  
White Clover ◽  
Instar Larva ◽  
Early Summer ◽  
Early Winter ◽  
First Instar ◽  
Sitona Lepidus ◽  
Microctonus Aethiopoides ◽  
Made In

Four experimental releases of the parthenogenetic strain of Microctonus aethiopoides from Ireland were made in early 2006 in the Waikato Manawatu (two sites) and Hawkes Bay By early winter establishment was confirmed at all sites with parasitism levels exceeding 10 in the target host Sitona lepidus a serious pest of white clover in New Zealand Subsequent monitoring revealed considerable betweensite variation At the Hawkes Bay and Manawatu Feilding sites where overwintering weevil adults were still present in October over 30 parasitism was found in newly emerged weevils in December 2006 In contrast at the Waikato and Manawatu Bulls sites where there was no overlap of host generations parasitism was below detectable levels during spring and early summer but recovered subsequently The Irish M aethiopoides appears to have four generations a year and diapauses over winter as a first instar larva Following the initial success releases have commenced in other regions

scholarly journals Collections of Microctonus aethiopoides Loan (Hymenoptera Braconidae) from Ireland

2006 ◽  
Vol 59 ◽  
pp. 290-296 ◽  
Author(s):  
M.R. McNeill ◽  
J.R. Proffitt ◽  
P.J. Gerard ◽  
S.L. Goldson
Keyword(s):  
Biological Control ◽  
New Zealand ◽  
Natural Enemy ◽  
Control Programme ◽  
Sitona Lepidus ◽  
Microctonus Aethiopoides

The biological control programme against Sitona lepidus (Gyllenhal) (Coleoptera Braconidae) commenced in 1998 with the first parasitised weevils imported into New Zealand quarantine in 2000 Extensive collections in Europe confirmed that the solitary endoparasitoid Microctonus aethiopoides Loan (Hymenoptera Braconidae) was the principal natural enemy of adult S lepidus With one exception all M aethiopoides reared from S lepidus collected in Europe have been arrhenotokous All M aethiopoides collected from Ireland are thelytokous which obviates the risk of hybridisation with an arrhenotokous Moroccan strain already established in New Zealand Levels of parasitism in S lepidus fieldcollected from Ireland were low (lt;8) and overall averaged 07 Rates of parasitism of S lepidus in New Zealand quarantine have averaged 25 but ranged from 0 to 95 Aspects relating to the rearing and management of Irish M aethiopoides are discussed including possible reasons for low rates of parasitism in quarantine

scholarly journals Clover root weevil in the South Island detection response and current distribution

2007 ◽  
Vol 60 ◽  
pp. 209-216 ◽  
Author(s):  
C.B. Phillips ◽  
M.R. McNeill ◽  
S. Hardwick ◽  
C.J. Vink ◽  
J.M. Kean ◽  
...  
Keyword(s):  
Biological Control Agent ◽  
New South ◽  
Control Agent ◽  
The South ◽  
The North ◽  
Sitona Lepidus ◽  
Clover Root ◽  
Detection Response ◽  
Microctonus Aethiopoides ◽  
Intensive Sampling

Sitona lepidus had spread throughout the North Island of New Zealand by 2005 and was first detected in the South Island in January 2006 when one individual was found at Harewood Christchurch Intensive sampling during February 2006 recovered only two additional specimens Several specimens were recovered from a separate Christchurch location in August 2006 Localised S lepidus populations were discovered near Richmond Nelson in April 2006 and in Rai Valley in May 2006 A website established in May 2006 to provide information about S lepidus was visited a mean of 135 times per month but it was never used to report possible new South Island infestations A biological control agent Microctonus aethiopoides was released at Richmond and Rai Valley between August 2006 and March 2007 By May 2007 it was parasitising from 4 to 14 of S lepidus adults which indicates it is likely to become permanently established

scholarly journals Modelling the farm scale impacts of clover root weevil herbivory

2006 ◽  
Vol 59 ◽  
pp. 312-316 ◽  
Author(s):  
T.A. White ◽  
P.J. Gerard
Keyword(s):  
Computer Simulation ◽  
New Zealand ◽  
N Fixation ◽  
Gross Margin ◽  
Pasture Production ◽  
Pasture Quality ◽  
Sitona Lepidus ◽  
Clover Root ◽  
Farm Scale ◽  
Additional Nitrogen

Clover root weevil (Sitona lepidus CRW) is a major New Zealand pasture pest This study used computer simulation and decision support modelling to simulate CRW herbivory estimate the longterm consequences on clover abundance pasture production and quality and financial implications to a typical sheep and beef farmer Three farm scenarios were explored the absence of CRW and the presence of CRW with and without additional nitrogen (N) For a hypothetical 325 ha Waikato sheep and beef farm CRW decreased mean clover abundance from 21 to 13 pasture production from 9200 to 7900 kg DM/ha/year pasture quality from 105 to 102 MJME/kg DM and N fixation from 60 to 42 kg N/ha/year This resulted in a 16 reduction in the annual gross margin However assuming current prices and costs and that an N response could be consistently achieved urea could be used to replace the reduction in N fixation without affecting profits

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