scholarly journals Response to clover root weevil outbreaks in South Canterbury, Otago and Southland; the agricultural sector and government working together

2016 ◽  
Vol 78 ◽  
pp. 117-122 ◽  
Author(s):  
S. Hardwick ◽  
C.M. Ferguson ◽  
P. Mccauley ◽  
W. Nichol ◽  
R. Kyte ◽  
...  
Keyword(s):  
Biological Control ◽  
New Zealand ◽  
White Clover ◽  
Agricultural Sector ◽  
Biocontrol Agent ◽  
Parasitic Wasp ◽  
Parasitoid Wasp ◽  
Clover Root ◽  
Working Together ◽  
Microctonus Aethiopoides

Clover root weevil was first discovered in the northern South Island in 2006, and an introduced biocontrol agent the parasitoid wasp Microctonus aethiopoides, was immediately released there in response. As the weevil spread southwards, ongoing releases and natural parasitoid dispersal generally supressed it to economically tolerable levels. However, mild winters in the southern South Island during 2013 and 2014 allowed weevil populations to grow and spread quicker than the parasitoid. This severely impacted white clover production and farm profitability in parts of South Canterbury, Otago and Southland, thus, scientists and industry conducted 18 months of intensive parasitoid releases of ca. 1.1 million parasitised weevils at 6000 sites. The parasitoid rapidly established at all 50 monitored release sites and dispersed from them. The biocontrol agent now occurs at all locations in South Canterbury, Otago, Southland, and elsewhere in New Zealand, where clover root weevil is present. Keywords: biological control, pest spread, parasitic wasp, Sitona obsoletus, Microctonus aethiopoides, South Canterbury, Southland, Otago

scholarly journals Clover root weevil tolerance of clover cultivars

2016 ◽  
Vol 78 ◽  
pp. 197-202 ◽  
Author(s):  
C.M. Ferguson ◽  
D.M. Barton ◽  
B.A. Philip
Keyword(s):  
New Zealand ◽  
Biocontrol Agent ◽  
Insect Pests ◽  
Parasitic Wasp ◽  
Cultivar Differences ◽  
Popular Belief ◽  
Single Mechanism ◽  
Clover Root ◽  
Major Loss ◽  
Microctonus Aethiopoides

Clover root weevil arrived in New Zealand about 20 years ago causing major loss of productivity as it progressively spread across the whole country. It is now largely controlled by an introduced parasitic wasp biocontrol agent Microctonus aethiopoides (Irish ecotype). However, management of insect pests should not rely on a single mechanism and clovers resistant or tolerant to this weevil would be a useful augmentation for farmers to have. This investigation reports on the suitability of 22 clover cultivars to attack from the weevil. Results have shown that contrary to popular belief, red clovers are not universally less favourable to the weevil than white clovers and usefully, within both species cultivar differences point to the possibility of resistance to this pest. Keywords: Clover root weevil, Sitona obseletus, clover cultivars

scholarly journals Unexpected parasitism of Douglas-fir seed chalcid limits biocontrol options for invasive Douglas-fir in New Zealand

2021 ◽  
Vol 74 (1) ◽  
pp. 70-77
Author(s):  
Sonia Lee ◽  
Simon V. Fowler ◽  
Claudia Lange ◽  
Lindsay A. Smith ◽  
Alison M. Evans
Keyword(s):  
Biological Control ◽  
New Zealand ◽  
Seed Production ◽  
Biocontrol Agent ◽  
Biological Control Agent ◽  
Parasitoid Wasp ◽  
Control Agent ◽  
Douglas Fir ◽  
Seed Predator ◽  
High Level

Douglas-fir seed chalcid (DFSC) Megastigmus spermotrophus, a small (3 mm long) host-specific seed-predatory wasp, was accidentally introduced into New Zealand in the 1920s. Concern over DFSC reducing Douglas-fir seed production in New Zealand led to an attempt at biocontrol in 1955 with the release, but failed establishment, of the small (2.5 mm long) parasitoid wasp, Mesopolobus spermotrophus. We investigated why DFSC causes little destruction of Douglas-fir seed in New Zealand (usually <20%) despite the apparent absence of major natural enemies. Douglas-fir seed collections from 13 New Zealand sites yielded the seed predator (DFSC) but also potential parasitoids, which were identified using morphology and partial COI DNA sequencing. DFSC destroyed only 0.15% of Douglas-fir seed. All parasitoids were identified as the pteromalid wasp, Mes. spermotrophus, the host-specific biocontrol agent released in 1955. Total parasitism was 48.5%, but levels at some sites approached 90%, with some evidence of density-dependence. The discovery of the parasitoid Mes. spermotrophus could indicate that the biocontrol agent released in 1955 did establish after all. Alternatively, Mes. spermotrophus could have arrived accidentally in more recent importations of Douglas-fir seed. The high level of parasitism of DFSC by Mes. spermotrophus is consistent with DFSC being under successful biological control in New Zealand. Suppression of DFSC populations will benefit commercial Douglas-fir seed production in New Zealand, but it also represents the likely loss of a potential biological control agent for wilding Douglas-fir.

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 Status of clover root weevil and its biocontrol agent in the South Island after six years.

2012 ◽  
pp. 171-175 ◽  
Author(s):  
C.M. Ferguson ◽  
M.R. Mcneill ◽  
C.B. Phillips ◽  
S. Hardwick ◽  
D.M. Barton ◽  
...  
Keyword(s):  
Biocontrol Agent ◽  
Parasitoid Wasp ◽  
The South ◽  
Natural Spread ◽  
Sitona Lepidus ◽  
Clover Root ◽  
Microctonus Aethiopoides ◽  
Made In

Clover root weevil was first discovered in the South Island in 2006. Since then its distribution has been monitored. Although not yet occurring throughout all the South Island, it is widespread and has become common in many regions. The first releases of a biocontrol agent, the Irish ecotype of the parasitoid wasp Microctonus aethiopoides, were also made in 2006, with more made as suitable weevil populations were detected. In all areas where the releases have been monitored the biocontrol agent has established and extensive natural spread has occurred from the earlier release sites. As a consequence it is now established extensively in the northern South Island. Targeted releases have established the agent in Canterbury, Otago and Southland. Keywords: Biocontrol, clover root weevil, Sitona lepidus, Microctonus aethiopoides

scholarly journals Toxicity of selected agrichemicals to clover root weevil and its parasitoid Microctonus aethiopoides

2014 ◽  
Vol 67 ◽  
pp. 256-266
Author(s):  
M.R. McNeill ◽  
T.M. Eden ◽  
V.M. Cave
Keyword(s):  
White Clover ◽  
Direct Contact ◽  
Laboratory Experiments ◽  
Biocontrol Agent ◽  
Insect Pests ◽  
Field Studies ◽  
Summer Period ◽  
Clover Root ◽  
Microctonus Aethiopoides ◽  
Insect Toxicity

White clover (Trifolium repens) crops are attacked by various insect pests including Sitona obsoletus (S lepidus) (CRW) Laboratory experiments were conducted to measure the toxicity of eight agrichemicals used against white clover insect pests or for weed control on CRW (parasitised and nonparasitised) and adults of its parasitoid Microctonus aethiopoides Laboratory experiments evaluated insect toxicity through direct contact with the agrichemical spray or via exposure to residues on clover foliage At field rates pymetrozine had the lowest impact on CRW biocontrol but had poor activity against nonparasitised CRW Taufluvalinate provided 60 control of CRW while having reduced impact on M aethiopoides adults (060 mortality) and was considered the best option in the field over the summer period Lambdacyhalothrin and diazinon were the most detrimental to CRW and its biocontrol agent when applied directly and through exposure to residues Diquat and an adjuvant caused some mortality to CRW and parasitoid Field studies are needed to corroborate these results

scholarly journals Clover root weevil biocontrol distribution in the North Island - release tactics and outcomes

2010 ◽  
pp. 85-89
Author(s):  
P.J. Gerard ◽  
D.J. Wilson ◽  
T.M. Eden
Keyword(s):  
Technology Transfer ◽  
White Clover ◽  
Trifolium Repens ◽  
Biocontrol Agent ◽  
Postal Survey ◽  
Far North ◽  
The North ◽  
Field Samples ◽  
Clover Root ◽  
Microctonus Aethiopoides

Clover root weevil (CRW) has become one of New Zealand's most serious pasture pests. An Irish ecotype of Microctonus aethiopoides has been released and established as a biocontrol agent. Since early 2006, field samples have been taken to monitor its spread and establishment. The biocontrol agent has established well at sites where 1 000-2 500 parasitised CRW were initially released, except in the Far North, and is spreading at around 15 km/year. Industry field personnel assisted with distributing 2 000 mini-releases (10 parasitised CRW) to areas where CRW was causing damage. One hundred farmers were sent a postal survey and feedback from 59 respondents showed the mini-release approach was successful in terms of distribution of the parasitoid, technology transfer and funder recognition. Based on natural spread from many of the release sites, it is predicted that the parasitoid will be present on most North Island farms by the end of summer 2010/2011. Keywords: Microctonus aethiopoides, biocontrol agent, white clover, Trifolium repens

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 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 lepidus Economic benefits of biological control of Sitona obsoletus (clover root weevil) in Southland pasture

2015 ◽  
Vol 68 ◽  
pp. 218-226 ◽  
Author(s):  
B. Basse ◽  
C.B. Phillips ◽  
S. Hardwick ◽  
J.M. Kean
Keyword(s):  
Biological Control ◽  
Parasitic Wasp ◽  
Cost Effective ◽  
Dairy Farms ◽  
Economic Benefits ◽  
Net Benefit ◽  
Parasitism Rates ◽  
Clover Root ◽  
Microctonus Aethiopoides ◽  
Parameter Values

Sitona obsoletus is a serious pasture pest in New Zealand where its rootfeeding larvae reduce white clover cover and nitrogen fixation To maintain production farmers may compensate by increasing inputs The parasitic wasp Microctonus aethiopoides Loan was introduced for biological control of S obsoletus and achieved parasitism rates exceeding 70 In Southland where S obsoletus was first detected in 2010 unusually severe and prolonged infestations during 2013 and 2014 prompted intensive biological control releases in 2014 and 2015 This study evaluated if they were cost effective in 2015 On dairy farms biological control returned 1478/ha/year or 23 million over the 158017 ha On sheep and beef farms the estimated return was 686/ha/year or 47 million over 719854 ha Monte Carlo simulations were used to estimate returns (/ha/year) using plausible ranges of model parameter values and returns were positive in at least 975 of simulations Biological control of S obsoletus has returned a net benefit in Southland

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