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

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

2001 ◽  
Vol 54 ◽  
pp. 147-151 ◽  
Author(s):  
S.L. Goldson ◽  
C. Phillips ◽  
M.M. McNeill ◽  
J.R Proffitt ◽  
R.P. Cane

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


2006 ◽  
Vol 59 ◽  
pp. 297-303 ◽  
Author(s):  
C.B. Phillips ◽  
I.I. Iline ◽  
C.J. Vink ◽  
L.M. Winder ◽  
M.R. McNeill

Two strains of Microctonus aethiopoides with differing host preferences have been released in New Zealand The first was released in 1982 to suppress Sitona discoideus a pest of lucerne and the second was released in 2006 for biological control of Sitona lepidus This paper describes three genetic approaches (esterase isozymes aldehyde oxidase allozymes and nucleotide sequences in a 676 bp region of the mitochondrial cytochrome oxidase subunit one gene) for distinguishing between the M aethiopoides strains A range of research applications for these methods is discussed


2012 ◽  
Vol 65 ◽  
pp. 186-191
Author(s):  
C.J. Vink

Two strains of the hymenopteran parasitoid Microctonus aethiopoides have been released in New Zealand for the biological control of Sitona weevil species One attacks Sitona discoideus a pest of lucerne and the other attacks Sitona lepidus a pest of clover Two other Microctonus species also attack weevils in pasture; M hyperodae was released for the biological control of Listronotus bonariensis and the native M zealandicus attacks Irenimus spp These Microctonus species can attack nontarget weevil hosts and the identification of the larvae of the different Microctonus species and the separation of adults of M aethiopoides strains can only be achieved by molecular methods This paper describes a simple polymerase chain reaction and restriction fragment length polymorphism (PCRRFLP) method for distinguishing between the two M aethiopoides strains M hyperodae and M zealandicus This PCRRFLP method requires minimal molecular equipment and is cheaper and/or faster than other molecular methods


2007 ◽  
Vol 60 ◽  
pp. 203-208 ◽  
Author(s):  
P.J. Gerard ◽  
T.M. Eden ◽  
S. Hardwick ◽  
C.F. Mercer ◽  
M.W.A. Slay ◽  
...  

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


2010 ◽  
Vol 63 ◽  
pp. 283-283
Author(s):  
P.J. Gerard ◽  
D.J. Wilson ◽  
T.M. Eden

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


2008 ◽  
Vol 61 ◽  
pp. 31-34
Author(s):  
T.M. Eden ◽  
M. Donald ◽  
P.J. Gerard

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


2009 ◽  
Vol 62 ◽  
pp. 414-414
Author(s):  
T.M. Eden ◽  
P.J. Gerard ◽  
J.J. Dymock ◽  
N. Ahmad

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


2000 ◽  
Vol 53 ◽  
pp. 168-172 ◽  
Author(s):  
P. Stevens

Leafrollers (Lepidoptera Tortricidae) are important pests of many horticultural crops Leafroller eggs in New Zealand are attacked by the trichogrammatid parasitoids Trichogrammatoidea bactrae and Trichogrammanza funiculatum (Hymenoptera Trichogrammatidae) Conventionally trichogrammatids are used for pest control through augmentation of numbers by making mass releases Laboratory tests have been carried out to ascertain the potential of the two eggparasitoid species to act as biological control agents for the key leafroller pests in New Zealand T funiculatum had a slightly slower developmental rate than T bactrae Temperature did not significantly affect the number of eggs parasitised by the adult parasitoids over their lifetime but temperature did affect the percentage of adult parasitoids emerging from parasitised eggs T bactrae had higher net reproductive rates and intrinsic rates of increase than T funiculatum and at this stage appears to be the most suitable candidate for an augmentative biological control programme


2020 ◽  
Vol 20 (2) ◽  
Author(s):  
Stephen L Goldson ◽  
Gary M Barker ◽  
Hazel M Chapman ◽  
Alison J Popay ◽  
Alan V Stewart ◽  
...  

Abstract New Zealand’s intensive pastures, comprised almost entirely introduced Lolium L. and Trifolium L. species, are arguably the most productive grazing-lands in the world. However, these areas are vulnerable to destructive invasive pest species. Of these, three of the most damaging pests are weevils (Coleoptera: Curculionidae) that have relatively recently been controlled by three different introduced parasitoids, all belonging to the genus Microctonus Wesmael (Hymenoptera: Braconidae). Arguably that these introduced parasitoids have been highly effective is probably because they, like many of the exotic pest species, have benefited from enemy release. Parasitism has been so intense that, very unusually, one of the weevils has now evolved resistance to its parthenogenetic parasitoid. This review argues that New Zealand’s high exotic pasture pest burden is attributable to a lack of pasture plant and natural enemy diversity that presents little biotic resistance to invasive species. There is a native natural enemy fauna in New Zealand that has evolved over millions of years of geographical isolation. However, these species remain in their indigenous ecosystems and, therefore, play a minimal role in creating biotic resistance in the country’s exotic ecosystems. For clear ecological reasons relating to the nature of New Zealand pastures, importation biological control can work extremely well. Conversely, conservation biological control is less likely to be effective than elsewhere.


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