HortResearch

Hamilton, New Zealand

HortResearch

Hamilton, New Zealand

Time filter

Source Type

Kriticos D.J.,CSIRO | Kriticos D.J.,University of Minnesota | Kriticos D.J.,New Zealand Forest Research Institute | Leriche A.,CSIRO | And 10 more authors.
PLoS ONE | Year: 2013

Biosecurity agencies need robust bioeconomic tools to help inform policy and allocate scarce management resources. They need to estimate the potential for each invasive alien species (IAS) to create negative impacts, so that relative and absolute comparisons can be made. Using pine processionary moth (Thaumetopoea pityocampa sensu lato) as an example, these needs were met by combining species niche modelling, dispersal modelling, host impact and economic modelling. Within its native range (the Mediterranean Basin and adjacent areas), T. pityocampa causes significant defoliation of pines and serious urticating injuries to humans. Such severe impacts overseas have fuelled concerns about its potential impacts, should it be introduced to New Zealand. A stochastic bioeconomic model was used to estimate the impact of PPM invasion in terms of pine production value lost due to a hypothetical invasion of New Zealand by T. pityocampa. The bioeconomic model combines a semi-mechanistic niche model to develop a climate-related damage function, a climate-related forest growth model, and a stochastic spread model to estimate the present value (PV) of an invasion. Simulated invasions indicate that Thaumetopoea pityocampa could reduce New Zealand's merchantable and total pine stem volume production by 30%, reducing forest production by between NZ$1,550 M to NZ$2,560 M if left untreated. Where T. pityocampa is controlled using aerial application of an insecticide, projected losses in PV were reduced, but still significant (NZ$30 M to NZ$2,210 M). The PV estimates were more sensitive to the efficacy of the spray program than the potential rate of spread of the moth. Our novel bioeconomic method provides a refined means of estimating potential impacts of invasive alien species, taking into account climatic effects on asset values, the potential for pest impacts, and pest spread rates. © 2013 Kriticos et al.


He J.,Nanyang Technological University | Austin P.T.,HortResearch | Lee S.K.,Nanyang Technological University
Journal of Experimental Botany | Year: 2010

Effects of elevated root zone (RZ) CO2 and air temperature on photosynthesis, productivity, nitrate (NO-3), and total reduced nitrogen (N) content in aeroponically grown lettuce plants were studied. Three weeks after transplanting, four different RZ [CO2] concentrations [ambient (360ppm) and elevated concentrations of 2000, 10000, and 50000ppm] were imposed on plants grown at two air temperature regimes of 28°C/22°C (day/night) and 36°C/30°C. Photosynthetic CO 2 assimilation (A) and stomatal conductance (gs) increased with increasing photosynthetically active radiation (PAR). When grown at 28°C/22°C, all plants accumulated more biomass than at 36°C/30°C. When measured under a PAR ≥600μmol m-2 s-1, elevated RZ [CO2] resulted in significantly higher A, lower gs, and higher midday leaf relative water content in all plants. Under elevated RZ [CO2], the increase of biomass was greater in roots than in shoots, causing a lower shoot/root ratio. The percentage increase in growth under elevated RZ [CO2] was greater at 36°C/30°C although the total biomass was higher at 28°C/22°C. (NO-3) and total reduced N concentrations of shoot and root were significantly higher in all plants under elevated RZ [CO2] than under ambient RZ [CO 2] of 360ppm at both temperature regimes. At each RZ [CO 2], NO3- and total reduced N concentration of shoots were greater at 28°C/22°C than at 36°C/30°C. At all RZ [CO 2], roots of plants at 36°C/30°C had significantly higher NO3- and total reduced N concentrations than at 28°C/22°C. Since increased RZ [CO2] caused partial stomatal closure, maximal A and maximal gs were negatively correlated, with a unique relationship for each air temperature. However, across all RZ [CO2] and temperature treatments, there was a close correlation between maximal A and total shoot reduced N concentration of plants under different RZ [CO2], indicating that increased A under elevated RZ [CO2] could partially be due to the higher shoot total reduced N. © 2010 The Author(s).


Spinelli F.,University of Bologna | Noferini M.,University of Bologna | Vanneste J.L.,HortResearch | Costa G.,University of Bologna
EPPO Bulletin | Year: 2010

The electronic-nose instrumentation has advanced rapidly during the past decade, as the need for highly sensitive, fast and accurate analytical measurements have considerably stimulated the interest in developing these sensors as diagnostic tools. Given that the pathogen-induced plant responses also include changes in emission of volatiles, the electronic-nose may represent a powerful and operator-friendly alternative for rapid and reliable screening of asymptomatic plant material. In the present study, the electronic nose EOS835 (Sacmi, Imola, Italy), based on metal oxide semiconductors, was used. EOS835 was able to detect asymptomatic apple and pear plants experimentally infected with Erwinia amylovora (fire blight). The electronic nose was also successfully tested for discriminating Botrytis and Sclerotinia rots on both green and yellow kiwifruits. Even if the electronic-nose can be successfully used in experimental conditions for early diagnosis of both pre- and post-harvest diseases, its practical application in open fields, nurseries and packing houses still requires further studies. © 2010 The Authors. Journal compilation © 2010 OEPP/EPPO.


Varkonyi-Gasic E.,HortResearch
Methods in molecular biology (Clifton, N.J.) | Year: 2010

Plant small RNAs are a class of 19- to 25-nucleotide (nt) RNA molecules that are essential for genome stability, development and differentiation, disease, cellular communication, signaling, and adaptive responses to biotic and abiotic stress. Small RNAs comprise two major RNA classes, short interfering RNAs (siRNAs) and microRNAs (miRNAs). Efficient and reliable detection and quantification of small RNA expression has become an essential step in understanding their roles in specific cells and tissues. Here we provide protocols for the detection of miRNAs by stem-loop RT-PCR. This method enables fast and reliable miRNA expression profiling from as little as 20 pg of total RNA extracted from plant tissue and is suitable for high-throughput miRNA expression analysis. In addition, this method can be used to detect other classes of small RNAs, provided the sequence is known and their GC contents are similar to those specific for miRNAs.


Nutritional supplements and a magnesium bolus and were used in lambs in a 22 factorial design to investigate the effect on growth, preslaughter stress measurements, muscle glycogen, and meat quality. In total, 64 Perendale lambs were used (32.70.53 kg, meanSEM). Feed supplemented animals received 150 g feed pellets day(-1) in addition to pasture grazing, and this increased growth from 183 to 207 g day(-1). Mean delivery of Mg from the boluses was 0.17 g day(-1) for 28 days, with no effect on growth rates, or any other of the variables measured. Urinary noradrenaline, adrenaline and cortisol did not differ between groups in the immediate pre-slaughter period. The meat ultimate pH was not different between groups and had a mean range of 5.47-5.53. Muscle residual glycogen did not differ between groups and had a mean range of 42-43 mmol kg(-1). Finally there were no differences in shear force values at all ageing times. The final shear force value of 2.5 kg F after 72 h ageing at 15C was a low value representing tender meat. These studies indicate that if nutrition is adequate and stress levels are low, there are no differences in meat tenderness of pasture fed lambs compared with those having feed supplements to increase growth rate.


PubMed | HortResearch
Type: Journal Article | Journal: Journal of chemical ecology | Year: 2013

Uptake and release of pheromone and behavioral inhibitor ofEpiphyas postvittanna by apple leaves was tested using field electroantennograms (EAG), trap catches to synthetic lures and virgin females, and chemical analysis. Trap catches in single apple trees (N=3) were monitored for six cycles of six days duration, using delta traps baited with synthetic pheromone. Polyethylene dispensers (0, 1, 10 per tree) releasing pheromone and inhibitor were present for only the first three days of each cycle. Application of 10 dispensers per tree resulted in complete disruption of trapping, which continued for one day after dispensers were removed. Over the three nights following the removal of the dispensers (days 4-6), trap catch was 0, 10, and 15% of the control catch. In contrast, the presence of only one dispenser per tree led to 0-20% of control catches, but on the three nights following dispenser removal catches were 35, 40, and 80% of the control catch. Field EAGs indicated significantly higher relative pheromone concentrations in the trees with 10 dispensers present, compared to trees with single dispensers, but removal of dispensers produced no detectable treatment effect compared to the control trees one day after dispenser removal. In a second experiment, releases of marked male moths into apple orchard plots following the removal of polyethylene dispensers (1 hr earlier that day) resulted in significantly lower catches in traps baited with virgin females in blocks that had been treated, compared to controls. Recovery of pheromone by solvent washing of leaves loaded with 50 g of the main component of the sex pheromone (1.26 g/cm(2)) was low (2.5%). Leaves held in a pheromone-saturated atmosphere were loaded with 0.0450.007 g pheromone/cm(2). Analysis of apple leaves taken from a pheromone-treated tree at different distances from the pheromone dispenser showed a decay of the pheromone load per square centimeter with increasing distance from the dispenser, as previously indicated by EAG.


PubMed | HortResearch
Type: Journal Article | Journal: Meat science | Year: 2011

The effect of electrical stimulation of lamb carcasses (n=269) or its absence (n=257) on shear force of m. longissimus thoracis et lumborum (LT) was monitored during ageing in pasture-fed merino lambs (n=526). The lambs were slaughtered on four different days allowing durations of between one to 10 days of recovery from pre-slaughter handling (yarding, weighing and crutching) that affected ultimate pH (pH(u)). The right LT was removed 20-40min post-slaughter, tightly-wrapped in cling film (prevents the muscle cross-section increasing and thus minimising shortening) and rapidly cooled to 15C to enter rigor mortis and age. At 0, 4, 24 and 72h post-slaughter, pH measurements and samples for shear force measurement were taken. Pre-slaughter handling had a significant negative effect on pH(u) and several days recovery were required for pH(u) to reach values associated with optimal meat quality as reflected by pH(u). Lambs with one and three days recovery (no significant difference between them) had a pH(u)>5.7 in 50% of the muscles and 19.4%>pH(u) 5.8. Whereas, in lambs with 8-10 days recovery (no significant difference between them), only 8% had a pH(u)>5.7 and 3.1%>pH(u) 5.8. Within each slaughter day electrically stimulated lambs were always more tender than non-stimulated lambs. For non-stimulated muscles at 72h, shear force values >40N occurred for 11.2% of the muscles: for electrically stimulated muscles at 72h, shear force values >40N occurred for 1.9% of the muscles. The rates of tenderisation were slower for intermediate pH(u) values resulting in higher shear force values at all ageing durations. With ageing at 72h for intermediate pH(u), non-stimulated muscles (n=38) 17.64% were >40N and for stimulated muscles (n=34), 7.9% were >40N.


PubMed | HortResearch
Type: Journal Article | Journal: Meat science | Year: 2011

Possible roles of the cellular messenger nitric oxide (NO) in post-mortem meat ageing were investigated in bull m. longissimus lumborum. Both enhancement and inhibition of NO activity had positive and negative effects, respectively, on early rates of ageing. These also correlated with direct measurements of NO in the meat samples. However, by 8 days of storage, the tenderness was not significantly different to non treated meat samples.


PubMed | HortResearch
Type: Journal Article | Journal: Journal of chemical ecology | Year: 2013

The absorption and release of the pheromone ofEpiphyas postvititana (Lepidoptera: Tortricidae),E 11-14: OAc andE,E 9, 11-14: OAc (95:5) by apple leaves was studied using electroantennograms (EAG) and sticky traps baited with pheromone-treated leaves. Leaves exposed to an airstream containing pheromone reached a constant level of pheromone release within 3 min. Release occurred over a period greater than 24 hr, following removal of leaves from the pheromone-saturated environment. Pheromone-treated leaves were effective as lures in sticky traps for at least three nights, although the average catch per night decrease logarithmically with time. In the field, pheromone was detected by EAG on leaves harvested from up to 25 cm away from a central point source of pheromone. The shape of a surface representing equal pheromone re-release from leaves around a central point source was defined by interpolation from a three-dimensional transect. Leaves harvested from 5 cm under the dispensers showed the highest pheromone release rate. Leaves downwind of the dispensers also had higher release of pheromone. In a treated orchard, significantly higher EAG measurements were recorded in the rows of trees that contained dispensers, compared to grass interrows or untreated trees. The implications of foliar pheromone adsorption and release on atmospheric concentrations and insect behavior require further investigation.


PubMed | HortResearch
Type: Journal Article | Journal: Journal of chemical ecology | Year: 2013

Through field trials and wind-tunnel studies, we have demonstrated that certain structural features of a sex-pheromone-baited delta trap affect catch of light-brown apple moth,Epiphyas postvittana, males, by influencing behaviors used to enter and exit the trap. Field catch of males was dependent upon length (and width) of the trap, with increases in length yielding linear increases in catch. In the wind tunnel, similar numbers of males entered the two traps, but significantly fewer males exited the longer trap within 1 min after entering it. Although males landed on the sticky surface at similar distances from the downwind entrances of the traps, they were stuck farther upwind on the longer trap. Thus, it is probable that the increase in field catch with increase in trap length relates to the increase in distance (and hence time) that males walk on the sticky surface, towards the pheromone source, before attempting to exit. The bottom barriers (as well as additional barriers at the top and sides) at the entrances of the trap also significantly influenced trap catch. The barriers apparently influence trap catch in two ways. Firstly, they hinder the exit of males from the trap, thus diverting males back into the trap and increasing their chance of being caught. Secondly, they influence where the male lands on the sticky surface; with higher barriers, males land farther upwind (i.e., nearer the source), and thus farther from an exit. Finally, as the source was suspended higher above a horizontal surface, greater numbers of males landed on the source. This result shows that the position where a maleE. postvittana lands is influenced by the relationship of the source to the surface and suggests that trap catch of males may similarly be influenced (i.e., by inducing males to land farther from the exits).

Loading HortResearch collaborators
Loading HortResearch collaborators