scholarly journals Leaf herbivory by clover root weevil adults how much do they eat

2005 ◽  
Vol 58 ◽  
pp. 126-130 ◽  
Author(s):  
P.J. Gerard ◽  
D.L. Hackell
Keyword(s):  
White Clover ◽  
Dry Matter ◽  
Early Summer ◽  
Leaf Damage ◽  
Dry Matter Loss ◽  
Leaf Consumption ◽  
Adult Feeding ◽  
Sitona Lepidus ◽  
Clover Root ◽  
Leaf Herbivory

Populations of adult clover root weevil (Sitona lepidus) can inflict significant numbers of their distinctive feeding notches on the leaves of white clover (Trifolium repens) plants However it is assumed that because white clover is bred for defoliation the damage on established plants has little impact Two experiments were undertaken to quantify the daily leaf consumption levels of adult weevils and how this varied with weevil size and sex clover cultivar and previous leaf damage Overall adults consumed between 075 and 12 mg dry matter/day depending on cultivar and sex Sexual differences were observed between two contrasting clover cultivars with females consuming more Grassland Prestige and males Grasslands Kopu Clover dry matter loss through adult feeding was estimated at about 50 kg/ha from early summer until midwinter in the Waikato the period of peak adult activity

scholarly journals Feeding habituation to red clover by clover root weevil adults

2003 ◽  
Vol 56 ◽  
pp. 129-132 ◽  
Author(s):  
P.J. Gerard ◽  
J.R. Crush
Keyword(s):  
White Clover ◽  
Trifolium Pratense ◽  
Red Clover ◽  
Feeding Preference ◽  
Choice Test ◽  
Feeding Preferences ◽  
Adult Feeding ◽  
Sitona Lepidus ◽  
Clover Root ◽  
Laboratory Trial

Red clover (Trifolium pratense) has been observed to persist longer than white clover (T repens) during field screening of legumes for tolerance of clover root weevil (Sitona lepidus) It has been suggested that this is linked to adult feeding preferences A laboratory trial was undertaken to confirm the feeding preference for white clover over red and to determine whether adults became habituated to red clover over time Groups of clover root weevil adults were caged on either white clover cv Grasslands Huia or 3 lines of Grasslands Pawera red clover At weeks 2 4 6 and 8 subsamples of adults were removed from the cages and were subjected to a 24 h choice test It was found that although adults showed a strong preference for white clover those that had been continuously fed red clover were more likely to feed on red clover in the choice test than those that had previously been fed white clover

scholarly journals Clover root weevil feeding and larval numbers on white and red clover seedlines

2002 ◽  
Vol 55 ◽  
pp. 252-257 ◽  
Author(s):  
R.N. Watson ◽  
J.P.J. Eerens ◽  
L.T. Davis
Keyword(s):  
White Clover ◽  
Red Clover ◽  
Field Trials ◽  
Egg Laying ◽  
Root Weight ◽  
Plant Vigour ◽  
High Performing ◽  
Adult Feeding ◽  
Sitona Lepidus ◽  
Clover Root

Two adjacent field trials were established in pasture to assess the relationship between clover vigour and clover root weevil (Sitona lepidus; CRW) populations Trial 1 contained 31 white clover and three red clover seedlines Trial 2 evaluated nine white clover seedlines selected for field vigour against clover nematodes All seedlines were visually scored for weevil adult feeding and plant vigour in summer and autumn In winter selected seedlines representative of the vigour range across the trials were sampled for CRW larval numbers and root weight There was a direct relationship between clover vigour in April and the number of CRW larvae establishing on seedlines A similar relationship was evident for CRW larvae per gram of root in June The results suggest that high performing clover lines such as Grasslands Kopu II were able to maintain productivity in spite of feeding pressure by CRW (tolerance) rather than by the suppression of CRW adults egg laying or larval numbers (resistance)

White clover vegetative persistence under pressure: sharpening New Zealand's competitive edge

2011 ◽  
Vol 15 ◽  
pp. 181-186
Author(s):  
P.J. Gerard ◽  
C.F. Mercer ◽  
B.A. Barrett
Keyword(s):  
Plant Breeding ◽  
White Clover ◽  
Dry Matter ◽  
Field Trials ◽  
Plant Health ◽  
Dry Matter Yield ◽  
Species Vulnerability ◽  
Sitona Lepidus ◽  
Clover Root ◽  
The Impact

White clover is relied upon as a cornerstone of the international competiveness of New Zealand's pastoral sector, despite its vegetative persistence and yield being constrained by pests and diseases. The species' vulnerability has been highlighted by the clover root weevil (Sitona lepidus) incursion, and the impact of increased residual pest and pathogen loadings under minimum tillage techniques. Plant breeding with a focus on plant health has made improvements in white clover performance, and there is scope to develop varieties that ensure a more resilient legume component in pastures. An exemplar outcome from this approach is improved vegetative persistence and dry matter yield under nematode and clover root weevil pressure, as shown in field trials of elite breeding material. An enhanced, unified plant breeding and plant health approach can increase the performance and vegetative persistence of white clover. Trait selections to increase resilience and dry matter yield include optimum root architecture; single and multi-gene resistance or tolerance mechanisms; multi-pest defence compounds; and symbiont:clover combinations enabling induced pest and disease resistance. Cost effective and timely plant health assays for plant breeding are essential. Improved breeding strategies will create value on-farm via perennial forage legumes that perform better under pressure from pests. Keywords: white clover, plant breeding, plant genetics, nematode, pest resistance, pest tolerance

The production and persistence of grazed irrigated pasture mixtures in south-eastern Queensland

1968 ◽  
Vol 8 (31) ◽  
pp. 177 ◽  
Author(s):  
RJ Jones ◽  
Davies J Griffiths ◽  
RB Waite ◽  
IF Fergus
Keyword(s):  
White Clover ◽  
Dry Matter ◽  
Rest Period ◽  
Early Summer ◽  
Temperate Species ◽  
First Year ◽  
Nitrogen Levels ◽  
South Eastern ◽  
Key Species ◽  
Significant Difference

Five irrigated pasture mixtures (four containing tropical and temperate species and one containing only temperate species (winter mixture) ) were compared under grazing at three nitrogen levels -nil, 100, and 300 lb N an acre a year as urea-over a four-year period 1960-1963. Pastures were grazed for approximately one week every six weeks with a twelve-week rest period in the winter of 1962 and 1963. Under this management mean annual yields of dry matter increased from 15,700 lb to 25,000 lb an acre over the four-year period. Pasture growth rates varied from over 90 lb DM an acre a day in early summer to 10-40 lb DM an acre a day in winter due to variations in radiation and temperature. Urea increased pasture dry matter yields and also the yields of nitrogen measured in 1961 and 1962. Mean response was 19 lb and 14.5 lb DM/lb N applied at the N100 and N300 rates respectively. Yield of nitrogen was increased by a mean of 79 lb an acre a year by application of urea, but there was no significant difference between rates. Dry matter responses to urea were small in winter and spring and large in summer and autumn. The N300 rate reduced the yield of white clover in the first two years of the pasture, but there was no reduction in the yield of white clover at the N100 rate compared with the N0 treatment. There were no significant differences in yield between the pasture mixtures in the establishment year. In subsequent years mixtures containing summer and winter species outyielded (P<0.001) the winter mixture, particularly in summer and autumn. The pattern of production was similar for all mixtures and there was no significant difference between mixtures in yield of nitrogen. Chloris gayana Kunth CV. Samford and Setaria sphacelata (Schum) Stapf and C. E. Hubbard CV. Nandi. were the most successful summer grasses and Bromus unioloides (Willd.) H.B.K. cv. Priebes, the best winter grass. Three Paspalum species failed to compete with the Setaria and three winter grasses were low yielding after the first year. Trifolium repens L. CV. Ladino was the only successful legume of three winter and three summer legumes sown. It enabled yields of 400 lb N an acre a year to be achieved, increased total soil nitrogen, and made an estimated contribution of 760-810 lb N an acre over the four-year period. It is considered to be the key species for irrigated pastures in south-eastern Queensland.

scholarly journals South Island distributions of clover root weevil and its biocontrol agent

2010 ◽  
pp. 227-232 ◽  
Author(s):  
C.B. Phillips ◽  
M.R. Mcneill ◽  
S. Hardwick ◽  
C.M. Ferguson ◽  
J.M. Kean
Keyword(s):  
Northern Hemisphere ◽  
White Clover ◽  
Biocontrol Agent ◽  
The North ◽  
Sitona Lepidus ◽  
Clover Root

Clover root weevil (Sitona lepidus) (CRw), a white clover pest from the Northern Hemisphere, was first found in the North island in 1996.

scholarly journals Effects of invertebrate pests on white and annual clovers in dryland soil

2010 ◽  
Vol 63 ◽  
pp. 235-240
Author(s):  
T.M. Eden ◽  
P.J. Gerard ◽  
D.J. Wilson ◽  
N.L. Bell
Keyword(s):  
Plant Growth ◽  
White Clover ◽  
Seedling Survival ◽  
Plant Root ◽  
Subterranean Clover ◽  
Dry Weight ◽  
Cyst Nematode ◽  
Shoot Dry Weight ◽  
Sitona Lepidus ◽  
Clover Root

Two experiments were carried out at Ruakura in soil taken from Whatawhata hill country pasture The relative susceptibility of several annual clovers (Trifolium spp) and perennial white clover (T repens) to slugs (Deroceras reticulatum) clover root weevil (Sitona lepidus) adults native crickets (Nemobius sp) or wheat bugs (Nysius huttoni) was tested by sowing seed of the clovers into separate rows in turf Susceptibility of clovers to clover cyst nematode (Heterodera trifolii) was tested by sowing each clover variety into Whatawhata soil inoculated with the nematode Plant growth was assessed in both experiments 4 weeks after sowing White clover was more susceptible to pests than the annual clovers with slugs and clover root weevil significantly reducing seedling survival and clover cyst nematode significantly reducing plant growth Subterranean clover (T subterraneum) cv Denmark was the least affected by pests showing no significant reduction in survival in the presence of slugs the most damaging pest and no significant decrease in plant root and shoot dry weight when exposed to nematodes

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 Nodule damage by clover root weevil larvae in white clover swards

2002 ◽  
Vol 55 ◽  
pp. 246-251 ◽  
Author(s):  
P.J. Gerard
Keyword(s):  
White Clover ◽  
Dry Matter ◽  
Dry Matter Production ◽  
Foliar Nitrogen ◽  
Nitrogen Levels ◽  
Matter Production ◽  
Clover Root ◽  
Small Plot ◽  
The Impact

The impact of clover root weevil larval populations was assessed in pure swards of Grasslands Prestige and Grasslands Kopu white clover in a small plot trial Nodule damage was very evident and both cultivars showed significant increases in nodule damage and decreases in percent foliar nitrogen in November in response to increasing winter larval numbers Dry matter production of Kopu in November was related to foliar nitrogen levels

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 Relationship between Sitona lepidus larval numbers and white clover seed production

2001 ◽  
Vol 54 ◽  
pp. 141-146
Author(s):  
P.J. Gerard
Keyword(s):  
Seed Production ◽  
White Clover ◽  
Trifolium Repens ◽  
Negative Impact ◽  
Early Flowering ◽  
Sitona Lepidus ◽  
Clover Root ◽  
Second Year ◽  
Clover Seed ◽  
Seed Crops

Plots of two cultivars of white clover (Trifolium repens) Grasslands Prestige (smallleaved early flowering) and Grasslands Kopu (largeleaved later flowering) were established in coldframe beds Clover root weevil (Sitona lepidus) larval numbers were manipulated to obtain winter larval densities ranging from 0 to over 1000/m2 Increasing winter larval densities increased Prestige seed production (g/m2) when harvested on 28 December and 10 January and the trend was still evident on 24 January No such relationships were found in Kopu for the early and middle harvests but at the late harvest increasing winter larval densities had a negative impact on seed production The results indicate that the effect of clover root weevil larvae on second year clover seed crops may vary substantially between cultivars and may even be positive rather than negative

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