Biology of the Introduced Biocontrol Agent Microctonus hyperodae (Hymenoptera: Braconidae) and Its Host Listronotus bonariensis (Coleoptera: Curculionidae) in Northern New Zealand

2013 ◽  
2011 ◽  
Vol 64 ◽  
pp. 283-283
Author(s):  
C.M. Ferguson ◽  
B.I.P. Barratt ◽  
D.M. Barton ◽  
D.J. Wilson

In 1990 Microctonus hyperodae was released in Otago and Southland as a biocontrol agent against Argentine stem weevil (ASW) (Listronotus bonariensis) At that time ASW was New Zealands major pasture pest but attained only sporadic importance in the southern South Island Since then possibly due to higher nutritional qualities of modern ryegrass cultivars and/or changes in annual thermal accumulation ASW has increased in significance Farmers once relied on endophytefree ryegrasses but now sow infected grasses While endophyte helps protect against ASW damage augmentation by M hyperodae parasitism is desirable Establishment and localised spread of M hyperodae was measured around the release sites but subsequent distribution over the wider southern South Island was not Between September and November 2011 52 pastures were sampled and ASW was found in all Microctonus hyperodae was reared from 18 of these pastures at levels of 133 parasitism but in 15 pastures parasitism was less than 7 The information gathered covers a limited period but suggests that M hyperodae is not as successful in the far south as in other parts of New Zealand The reasons for this and possible implications warrant further investigation both to understand the situation and to investigate if supplementary releases of M hyperodae can be usefully undertaken


2011 ◽  
Vol 64 ◽  
pp. 55-62 ◽  
Author(s):  
A.J. Popay ◽  
M.R. McNeill ◽  
S.L. Goldson ◽  
C.M. Ferguson

Recent sampling in Waikato and Taranaki shows that Argentine stem weevil (Listronotus bonariensis) can still cause major damage to susceptible ryegrass pastures despite the introduction of the parasitoid Microctonus hyperodae in 1991 Percentage of tillers with L bonariensis larval damage in diploid and tetraploid perennial ryegrass and Italian ryegrass in January and February were between 11 and 68 High egg numbers were noted on occasion Although there is evidence that M hyperodae reduces host populations parasitism levels vary considerably between years in Canterbury and are low in Otago and Southland where high populations of L bonariensis have recently been recorded Factors that may be lessening the impact of M hyperodae are considered These include asynchronous generations of the parasitoid and its host host behavioural adaptations compensatory oviposition and inhibition of flight in parasitised individuals leading to low levels of parasitism in new pastures


2002 ◽  
Vol 55 ◽  
pp. 272-279 ◽  
Author(s):  
M.R. McNeill ◽  
P.J. Addison ◽  
J.R. Proffitt ◽  
C.B. Phillips ◽  
S.L. Goldson

The braconid parasitoid Microctonus hyperodae was released in New Zealand for biological control of Argentine stem weevil Listronotus bonariensis The initial 1991 research introduction involved the release of 99000 parasitised L bonariensis Between 1991 and 1998 a further 660000 M hyperodae were released as part of commercial contracts and research programmes Commercial contracts resulted in the widespread release of the parasitoid in the North Island with South Island releases mainly confined to midCanterbury There were eight geographic populations originally collected from South America and these were maintained separately in the laboratory Excluding the Mendoza population which was founded on a single female an average of 91040 M hyperodae was released from each of the seven remaining populations Parasitised L bonariensis were released at a total of 121 sites and the parasitoid established at 118 (975) Based on the distribution of releases in New Zealand and the results of surveys it is estimated that M hyperodae is now very widely distributed in the North Island with more limited distribution in the South Island


2002 ◽  
Vol 55 ◽  
pp. 267-271 ◽  
Author(s):  
I.I. Iline ◽  
C.B. Phillips ◽  
S.L. Goldson ◽  
H.M. Chapman

Eight South American geographic populations of the parasitoid Microctonus hyperodae Loan (Hymenoptera Braconidae) have been released in New Zealand to help suppress the pasture pest Listronotus bonariensis (Kuschel) (Colepotera Curculionidae) Parasitoids from each South American population were released in equal numbers throughout New Zealand It was postulated that the population(s) best suited to the conditions encountered at each New Zealand release locality would eventually become prevalent there Genetic markers which will enable the South American populations that have become successful in New Zealand to be identified are being developed and this paper reports a preliminary assessment of M hyperodae allozyme variation Malate dehydrogenase (MDH) was the only variable enzyme of the six that were assayed and it exhibited variation consistent with the presence of two alleles All parasitoids from east of the Andes (Argentina Brazil and Uruguay) were heterozygous (MDHa/MDHb) while all those from the west (Chile) were homozygous (MDHa/MDHa) This corroborates earlier morphometric evidence of genetic differentiation between South American populations and indicates that work with additional enzymes should yield more markers


1996 ◽  
Vol 86 (2) ◽  
pp. 101-108 ◽  
Author(s):  
B.I.P. Barratt ◽  
A.A. Evans ◽  
P.D. Johnstone

AbstractThe parasitoidsMicroctonus hyperodaeLoan andM. aethiopoidesLoan have been introduced into New Zealand to control the forage pestsListronotus bonariensis(Kuschel) andSitona discoideusGyllenhal, respectively. Laboratory experiments were carried out to investigate the effect of host–parasitoid ratio, and exposure time on host survival, parasitism, oviposition and feeding. Cages of 20 field collected weevils were exposed to 0, 1, 3 or 6 parasitoids for 0, 1, 12 or 48 hours, maintained until parasitoid pupal emergence, and surviving weevils dissected. Over the ranges studied, increasing parasite number, and to a greater extent, period of exposure of parasitoids to their hosts increased parasitism levels.Microctonus aethiopoidesachieved higher levels of parasitism inS. discoideusat the lower parasitoid contact treatments than didM. hyperodaeinL. bonariensis. Fecundity in unparasitized weevils was progressively reduced in bothL. bonariensisandS. discoideusin relation to increasing exposure to parasitoids. Feeding was reduced by about 40% inL. bonariensisfor at least four days after parasitoids were removed, and inS. discoideusfor the duration of the experiment, averaging 15%. Results were discussed in relation to possible mechanisms of indirect effects of parasitoids on unparasitized hosts.


2010 ◽  
Vol 63 ◽  
pp. 272-272
Author(s):  
J. Vereijssen ◽  
K.F. Armstrong ◽  
L.M. Winder ◽  
S.L. Goldson

The braconid endoparasitoid Microctonus hyperodae was successfully introduced into New Zealand in 1991 to control the exotic pastoral pest Argentine stem weevil (ASW) The wasp parasitises adult ASW and the weevil normally dies only when the fifthinstar parasitoid larva emerges However during biocontrol research over the last 20 years premature mortality of ASW has been observed under conditions of high parasitoid pressure in the field and laboratory It was hypothesised that this occurs because of injection of venom without an egg To conclude absence of a parasitoid egg in a prematurely dead weevil a sensitive method is needed to detect a newly oviposited parasitoid egg However this cannot be confirmed by visual observation or by dissection because fresh tissue is subsequently needed to detect venom A molecular method was therefore developed Firstly to model oviposition eggs were dissected from the ovaries of an adult parasitoid and one ovarian parasitoid egg was used to spike ASWs that had been dissected to confirm absence of parasitism Secondly multiplexPCR was successful in detecting a single ovarian egg in ASW This result greatly benefits research into the observed premature mortality of ASW after being exposed to M hyperodae


1999 ◽  
Vol 89 (5) ◽  
pp. 423-431 ◽  
Author(s):  
S.L. Goldson ◽  
J.R. Proffitt ◽  
D.B. Baird

AbstractFlight byListronotus bonariensis(Kuschel) in Canterbury, New Zealand varied greatly both within and between seasons; no winter flight was detected between mid-May and mid-August. Predisposing conditions for flight were found to be >19degC, rh <81% and windspeed <10.8 km h–1. Three flight phases with different characteristics were identified when approximately equal numbers of weevils were trapped. These were between mid-August and early December (overwintered weevils), between early December and mid-March (first summer generation weevils) and mid-March and mid-May (first and second generation weevils). The proportion of individuals with developed flight musculature wasc. 8% in the first phase and 30% in the last phase; muscle development was delayed in the mid-phase. First phase weevils with flight muscles werec. 20 times more likely to fly than those in the last. A very weak inverse relationship was observed between developed flight musculature and the presence or absence of eggs. Similarly, there was a very weak inverse relationship between weevil ground densities and the proportion with developed flight muscles. Levels of parasitism byMicroctonus hyperodaeLoan amongst trapped weevils were far less than that on the ground, indicating that it inhibits flight and may explain the relatively slow dispersal of the parasitoid. It was concluded that the adaptive implications of flight could be linked to escape responses from desiccating microclimates rather than dispersal from crowded habitats.


2000 ◽  
Vol 53 ◽  
pp. 425-429 ◽  
Author(s):  
C.B. Phillips ◽  
M.R. McNeill ◽  
R.P. Cane ◽  
S.L. Goldson

Releases of eight South American geographic populations of the parasitoid Microctonus hyperodae Loan (Hymenoptera Braconidae) began in New Zealand in 1991 to assist in the suppression of the pasture pest Listronotus bonariensis (Kuschel) (Coleoptera Curculionidae) A morphometric analysis of M hyperodae adults collected from five of the New Zealand release sites during 199294 indicated that parasitoids derived from west of the South American Andes were significantly less successful than those from east of the Andes It was postulated that parasitoids from west of the Andes were either poorly adapted to New Zealand conditions and unable to establish or were reasonably well adapted to New Zealand conditions but were slightly less competitive than parasitoids from east of the Andes Preliminary results from a field experiment where parasitoids from east and west of the Andes were released separately strongly support the latter possibility


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