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

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 Managing white clover for productive and profitable sheep farming in Southland

2000 ◽  
pp. 137-140
Author(s):  
J.P.J. Eerens ◽  
D.L. Ryan
Keyword(s):  
Nitrogen Fixation ◽  
New Zealand ◽  
Perennial Ryegrass ◽  
White Clover ◽  
Dry Matter ◽  
Research Station ◽  
Pasture Management ◽  
Pasture Production ◽  
Clover Root ◽  
Pastoral Farming

White clover is often listed as one of the factors contributing to profitable pastoral farming in New Zealand. The positive aspects of white clover have been presented in a balanced manner in publications by scientists, environmentalists and farmers able to exploit these positive aspects. Increasingly, pastures contain sub-optimal levels of clover, as a result of pasture management that is detrimental to clover, including the increasing use of fertiliser nitrogen. In some regions of New Zealand, farmers can legitimately point to pests such as the clover root weevil and factors such as the ryegrass endophyte as causing restrictions in clover production, but this is less the case in Southland. Environmental conditions in Southland are well suited for ryegrass-white clover pastures. Wellmanaged ryegrass-white clover pastures containing the best regional cultivars can achieve high financial returns. A number of trials at the Gore Research Station are reviewed; they demonstrated that on mixed ryegrass-white clover swards farmers can produce nearly 25% more dry matter, 40% more carcass weight and 25% more wool than on pastures with ryegrass alone receiving 270 kg N/ha/year. The yield advantage would have been greater still if they were compared with typical Southland pastures. Not only was 180 kg more carcass and 17 kg more wool produced per hectare on mixed swards, but nitrogen fixation by clover produced more than $300 worth of nitrogen per hectare. The yield advantage achievable from the ryegrass-white clover swards requires specific pasture management, particularly in spring- summer and the use of adapted white clover cultivars. Keywords: cultivars, Lolium perenne, nitrogen, pasture production, perennial ryegrass, set stocking, Trifolium repens, white clover, wool

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

Kikuyu and annual pasture: a characterisation of a productive and sustainable beef production system on the South Coast of Western Australia

2003 ◽  
Vol 43 (8) ◽  
pp. 769 ◽  
Author(s):  
M. M. McDowall ◽  
D. J. M. Hall ◽  
D. A. Johnson ◽  
J. Bowyer ◽  
P. Spicer
Keyword(s):  
Soil Water ◽  
Western Australia ◽  
Production System ◽  
The South ◽  
Deep Drainage ◽  
Gross Margin ◽  
Combined System ◽  
Pasture Production ◽  
Pasture Quality ◽  
Lactation Phase

Production parameters and water use of kikuyu (Pennisetum clandestinum) and annual-based pastures were monitored for a beef weaner production system from 1998 to 2000 in a paddock-scale demonstration on the south-east coast of Western Australia. A paired paddock (40–105 ha) comparison was carried out between a kikuyu-based pasture (DSKikuyu) and temperate annual pasture (DSAnnual), with comparative measurements covering pasture production, composition and quality, and soil water deficits and drainage. The stocking rates for the paddocks were determined by the pasture productivity and cow P8 fat depth in the 'lactation phase' (April–December), and by sward management and soil stability imperatives in the 'dry cow phase' (January–March). Cow liveweight and P8 fat depth and calf liveweight were compared during the 'lactation phase'. Kikuyu and annual pasture had similar carrying capacities through the 'lactation phase'. Kikuyu pasture carried more animals than annual pasture through the 'dry cow phase' (late summer and autumn) in all years. During late autumn, cattle were destocked from the annual pasture to reduce the risk of wind erosion and 'crash grazed' on the kikuyu pasture so as to reduce competition between kikuyu and regenerating annual grass and legume species. The comparative quality and productivity of the kikuyu pasture in the lactation phase (winter and spring) was positively correlated with the level of winter legume present. When a similar level of winter legume was measured in the kikuyu pasture relative to the annual pasture (in 1998), the pasture quality, cow liveweight and condition and calf weaning weights were all comparable between the 2 pasture types. When a low legume component was recorded in the kikuyu pasture, the pasture quality and cow liveweight and condition were poorer than the annual pasture. The kikuyu pasture growing on deep sandy soil developed a larger (mean 37 mm) soil water deficit than the annual pasture over the measurement period, and in particular from November to March. When integrated over a farm where kikuyu covers 40% of the total area, as was the case in this experiment, the resulting deep drainage was calculated to be just over half that of an equivalent whole farm of annual pasture. Over the 3 years of monitoring, the combined system of annual and kikuyu pasture was calculated to have an annual gross margin 19% higher than the annual pasture alone. The major source of difference was no requirement for supplementary feed in the kikuyu–annual pasture system. This difference was limited however, by lighter post-weaning sale weights of cull cows from the kikuyu pasture in 'poor legume' years. There was no difference of calf weaning weights between treatments.There is considerable opportunity to improve on this gross margin, through achieving a consistent strong presence of legume in the kikuyu pasture through winter and spring.

The bionomics of an invasive speciesSitona lepidusduring its establishment in New Zealand

2009 ◽  
Vol 100 (3) ◽  
pp. 339-346 ◽  
Author(s):  
P.J. Gerard ◽  
S.L. Goldson ◽  
S. Hardwick ◽  
P.J. Addison ◽  
B.E. Willoughby
Keyword(s):  
New Zealand ◽  
White Clover ◽  
Sitona Lepidus ◽  
Two Generations ◽  
Boom And Bust ◽  
Clover Root ◽  
Exotic Pest ◽  
Boom And Bust Cycle ◽  
Clover Content ◽  
Adult Abundance

AbstractThe egg, larval, pupal and adult abundance of the clover root weevilSitona lepidusGyllenhal (Coleoptera: Curculionidae) was monitored at three sites for the first ten years following the discovery of this exotic pest in the Waikato region of New Zealand. The species went through an initial boom and bust cycle at two sites, with populations reaching up to 1800 larvae m−2. Thereafter, winter larval populations were relatively stable, ranging between 450–750 m−2. Unlike in the Northern Hemisphere,S. lepiduswas found to have two generations a year in the Waikato region of New Zealand. Pasture white clover content at the time of peak adult numbers was positively related to the subsequent peak larval populations for each generation. The factors contributing to the emergence ofS. lepidusas one of the most important pasture pests in New Zealand are discussed.

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 Entomopathogenic nematodes as biocontrol agents in New Zealand agriculture: a case study

2008 ◽  
pp. 171-175
Author(s):  
N.L. Bell ◽  
L.T. Aalders ◽  
T.C. Rohan
Keyword(s):  
New Zealand ◽  
Entomopathogenic Nematodes ◽  
Heterorhabditis Bacteriophora ◽  
Steinernema Carpocapsae ◽  
Biocontrol Agents ◽  
Control Soil ◽  
Sitona Lepidus ◽  
Clover Root ◽  
Wax Moth

Entomopathogenic nematodes (EPNs) have been used experimentally to control insects in pastures and in this study we investigated the use of EPNs against clover root weevil. We tested the ability of two EPNs (Steinernema carpocapsae and Heterorhabditis zealandica) to control soil-dwelling stages of clover root weevil in a Waikato pasture Keywords: Sitona lepidus, Heterorhabditis bacteriophora, larvae, pupae, Galleria, wax moth

scholarly journals Colonisation of renovated pastures in Waikato by four coleopteran species

2004 ◽  
Vol 57 ◽  
pp. 304-309 ◽  
Author(s):  
S. Hardwick
Keyword(s):  
New Zealand ◽  
White Clover ◽  
Soil Type ◽  
Field Trial ◽  
Pest Species ◽  
Soil Drainage ◽  
Dispersal Behaviour ◽  
Sitona Lepidus ◽  
Costelytra Zealandica ◽  
Farm Scale

In autumn 1998 a farm scale replicated field trial was established in Waikato New Zealand to measure the productivity of combinations of old and new ryegrass and white clover cultivars Colonisation in the first two years of the trial by Costelytra zealandica Heteronychus arator Naupactus leucoloma and Sitona lepidus was monitored By the end of winter 2000 no difference in densities of any of the pest species monitored could be attributed to cultivar treatments However dispersal behaviour and soil type did have a significant effect on pest densities Naupactus leucoloma which disperses by walking was found in greatest densities on the edges of the trial Costelytra zealandica which disperses by flying was initially aggregated in paddocks with shelterbelts Heavy infestations of H arator which also disperses by flying were associated with good soil drainage Sitona lepidus which disperses by flying was evenly distributed across the trial

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