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Potential of the mirid bug, Engytatus nicotianae, for the biological control of the tomato-potato psyllid in greenhouses
No full textThe tomato-potato psyllid (TPP), Bactericera cockerelli, is a serious pest of solanaceous crops. As an alternative to the use of insecticides, we tested the potential of the mirid bug Engytatus nicotianae (adults) as a biocontrol agent of TPP on greenhouse tomato plants. The experiment comprised: a) a laboratory choice feeding assay to investigate the preferences of E. nicotianae when offered TPP eggs and nymphs and b) a greenhouse experiment to assess the potential of E. nicotianae as a biocontrol agent under close to commercial conditions. The laboratory choice experiment highlighted a preference by E. nicotianae for the first two TPP instars, followed by the third instar and then the eggs. Consumption of fourth instars occurred only when all other life-stages had been consumed. In the cage experiment, the E. nicotianae-only treatment produced the same numbers of fruits and flowers as the control (no insects), even though TPP feeds on tomato leaves and stems. In contrast, the TPP-only treatment resulted in fewer fruits and flowers. The simultaneous introduction of E. nicotianae and TPP markedly reduced TPP build up compared to the TPP-only treatment and prevented the pest from establishing at all in four of the seven replicates of the experiment. These findings suggest that E. nicotianae should be considered as a potential biocontrol tool against TPP and further research is needed to determine an optimum release configuration
Interacting impacts of climate, eutrophication, and artificial drainage on aquatic greenhouse gas (CO₂, CH₄, N₂O) emissions
No full textCoastal areas are increasingly subject to both direct (land-use change) and indirect (climate change) anthropogenic pressures. Land-use change may produce ‘hot spots’ of aquatic greenhouse gas emissions through the combination of increased nutrient run-off and the creation of small artificial waterways (e.g., farm ponds and drains), but predicting future emissions from these landscapes also requires understanding the effects of extreme weather events. Here dissolved CO₂, N₂O, and CH₄ concentrations were measured both across the aquatic continuum (ponds, ephemeral ditches, irrigation drains, streams, tidal rivers, and lagoonal estuaries), and continuously over an extreme winter storm event. Combining these measurements with hydrodynamic modelling revealed the disproportionate greenhouse gas emissions contributed by small, nutrient-loaded waterways: ephemeral drains cover 5% of the total water surface area but produce 50% of emissions (4 – 7 Mmol d¯¹ CO₂-equivalents). However, in-situ storm measurements revealed that high wind winter storms can produce a 16-fold increase in estuary emissions (18 Mmol d¯¹ CO₂-equivalent) that dwarfs these ‘hot spot’ emissions. Wind-enhanced water-air gas transfer (k₆₀₀ from 5 cm h¯¹ under calm conditions to >30 cm h¯¹) was not the primary driver of storm emissions. Instead, storm conditions enhanced pore-water exchange with the eutrophied sediments and decreased primary productivity from floating macrophytes: CH₄ concentrations increased from 110 nM under fair weather conditions to 1,400 nM within hours of winds reaching 90 km h¯¹. Under current climate conditions these types of storms only occur a few days per season, but by triggering coastal emissions they can increase the seasonal greenhouse gas emissions from across the entire catchment by 30-50%. Together these findings demonstrate that including both high-wind predictions and small, artificial drainage features will be critical for accurately predicting future coastal climate feedback loops
High consumer acceptance of mutton and the influence of ageing method on eating quality
No full textTo compare the eating quality (EQ) of wet (WA) and dry aged (DA) mutton longissimus thoracis et lumborum (LTL) and semimembranosus (SM), bone-in leg and loin primals from 81 merino cull ewes were WA or DA for 14, 28, 42 or 56 days. Untrained consumers (n = 540) assessed the excised LTL and SM for EQ (tenderness, juiciness, liking of flavour and overall liking, 0–100), quality grade and respective willingness to pay (WTP). LTL scored higher than SM for EQ, P 70 and mean SM EQ scores >54. Ageing method had no significant effect on LTL or SM EQ (P > 0.05 for all consumer scores). Ageing beyond 14 days improved SM and LTL tenderness. Consumers most often graded LTL and SM quality grades as “better than everyday” and “good everyday” respectively; corresponding WTP was 26.90 AUD/kg. Extended ageing periods improved mutton tenderness
Meat insights: Uruguayan consumers´ mental associations and motives underlying consumption changes
No full textA telephone survey (n = 601) was conducted in Uruguay to explore participants' mental associations with meat and the underlying reasons changes in the quantity and type of meat consumed. Participants mentioned mostly positive associations with meat's culinary and cultural aspects and its nutritional value as source of high-quality protein. Other associations were related to meat production, specific types of meat and cuts, meat consumption and pleasure, while price was perceived negatively. Animal welfare concerns emerged as a relevant association, but minor references were made to the effects of meat production on the environment. Changes in the amount and type of meat consumed (higher pork, chicken and cheaper cuts and beef) in the last year were mainly due to price followed by health reasons. Results emphasize the strong meat culture among Uruguayans and reveal that changes in the amount and type of meat consumed last year relate to external (price) or egoistic (health) rather than altruistic motives (ethical or environmental concerns)
Meat consumption and consumer attitudes – a New Zealand perspective
No full textMeat consumption and consumer attitudes – a New Zealand perspectiv
A new perspective on the linkages between tourism demand and business cycles
No full textBusiness cycles, that is, the irregular fluctuations in economic activity, affect tourism demand—this is a stylized fact in tourism research. And it is well-founded. After all, as incomes rise, so does the consumption of goods and services, including tourism; tourism falls into the category of normal (or luxury) goods and services. This reasoning, however, may offer no assurance to tourism-exporting countries. International tourists, who have many destinations to choose from, may prefer one over another. Thus, the benefits accruing from rising tourism demand abroad would differ across tourism-exporting countries: each would be concerned with the impact of foreign business cycles on its own tourism exports. Therefore, several important questions arise for a tourism-exporting country: Are foreign business cycles correlated with demand for its tourism services? If yes, how strong are the correlations? What is the lag with which tourism demand is affected by business cycles? Does seasonality, which typifies tourism demand, mask the association between business cycles and tourism demand cycles? This study is devoted to answering these questions in the context of the demand for New Zealand (NZ) tourism by employing the recently developed Hamilton (2018) filter as well as the frequently used Hodrick-Prescott filter (Hodrick & Prescott, 1997). While the latter is foundational to numerous analyses in economics and tourism research, the former is relatively new. We also use a difference filter to perform robustness checks. Thus, from a methodological standpoint, we contribute to the literature by presenting the first detailed comparative analysis of business cycles and tourism demand linkages using three different data filters
The role of credence attribute claims in food product launch - A comparative study of New Zealand and Australia
No full textThis paper aims to empirically investigate the role of claims of credence attributes in the launch of food and drink products using a large dataset of new product development by food companies in Australia and New Zealand. Multinomial regression models are employed to analyze the association between the type of product launch and the positioning claims adopted by firms in the two markets. The results provide evidence that claims of credence attributes play an important role in the product launch strategy of firms in both Australia and New Zealand. Food companies tend to choose the most cost-effective strategies to launch products with credence attributes. Hence, claims that are seen as most important for consumers are more likely to be engendered for the more costly launch approach. For example, the attribute of “environmental-friendly” is highly important in both markets and its use is related to launching brand new products which generally is the most costly launch strategy. In contrast, other credence attributes, such as “ethical” and “safety”, are linked to relatively simpler and cheaper strategies, such as new packaging and new extension. Note that whilst the attribute of “health and nutrition” is regarded as an important claim to firms in the Australia market, it is not related to any product launching approaches in the New Zealand market. Given most studies on credence attributes have focused on the consumer side, results of this study fill in the gap of understanding how food suppliers respond to consumer demand for food products with credence attributes
Responses to drought stress and water logging of 12 diverse pastoral lines in pakihi podzol soil : A dissertation submitted in partial fulfilment of the requirements for the Degree of Bachelor of Science with Honours at Lincoln University
No full textNew Zealand's farm systems rely on grazed pasture and fodder crops as the critical feed for livestock. 40% of New Zealand's agricultural land is in pastures which support livestock industries, generating an annual export revenue of NZ$33.8 billion. Due to climate change and tightening environmental regulations such as the 190 N application limit, the status quo perennial ryegrass white clover pasture is becoming less suitable for production in many regions of New Zealand, where water stress and waterlogging stress are increasing in frequency. Diverse pastures are a potential means to improve intra-annual yield stability and increase nitrogen fixation. To determine which species could be suitable for use in a diverse pasture mix for a farm conversion in Golden Bay, a randomised block experiment was set up to test 12 lines of perennial forages. The species included white clover, red clover, Alsike clover, Lotus pedunculatus, perennial ryegrass, cocksfoot, prairie grass, tall fescue and chicory. The species received treatments of waterlogging and drought stress. Drought plants were maintained just above PWP for 42 days, while waterlogging plants were submerged for 15 days, then removed and replaced in 3-day cycles according to stress levels. Under drought stress, all species had significantly reduced total biomass yields, ranging from a 55 % reduction in Alsike clover to a 25 % reduction in Caucasian clover. Under waterlogging, only white clover and red clover showed significant decreases in aboveground dry matter, but most species had at least an 80 % increase in senescence. Other traits measured included plant dry matter, photosynthesis, stomatal conductance, water potential, leaf senescence, leaf damage, SPAD and soil moisture. It was found that, on average, all other grass species were more tolerant in most traits than perennial ryegrass under drought, and all fescue lines were more tolerant than ryegrass under waterlogging. Compared with white clover, red clover and L. pedunculatus were more tolerant to drought and waterlogging, and Alsike clover performed similarly. The findings suggest suggest merit for examining diverse pastures based on L. pedunculatus, white cover, red clover, Alsike clover, chicory, cocksfoot, Continental and mediterranean fescues in the Golden Bay climate on Pakihi podzol. Among the legumes, L. pedunculatus was the best performing species for environments that experience drought as well as waterlogging. Despite similar biomass to white clover and red clover under drought and higher productivity under waterlogging, lotus had lower levels of senescence under both stresses, retaining greater root biomass under waterlogging. In grasses, hybrid tall fescue had the lowest levels of senescence under both stresses. Among the grass lines there were similar productivity levels and stress-induced changes. However, under both stresses, the fescue lines maintained the lowest levels of senescence among the grasses. Therefore, they could be tested as a suitable base to replace the traditional perennial ryegrass-based pasture used on Pakihi podzol in high rainfall environments. Future work under field conditions is needed to substantiate the findings from this research and progress the understanding of how the species interact with each other in response to the environment and grazing
Quantitative genetic analysis reveals potential to breed for improved white clover growth in symbiosis with nitrogen-fixing Rhizobium bacteria
Get PDFWhite clover (Trifolium repens) is integral to mixed pastures in New Zealand and temperate agriculture globally. It provides quality feed and a sustainable source of plant-available nitrogen (N) via N-fixation through symbiosis with soil-dwelling Rhizobium bacteria. Improvement of N-fixation in white clover is a route to enhancing sustainability of temperate pasture production. Focussing on seedling growth critical for crop establishment and performance, a population of 120 half-sibling white clover families was assessed with either N-supplementation or N-fixation via inoculation with a commercial Rhizobium strain (TA1). Quantitative genetic analysis identified significant (p< 0.05) family additive genetic variance for Shoot and Root Dry Matter (DM) and Symbiotic Potential (SP), and Root to Shoot ratio. Estimated narrow-sense heritabilities for above-ground symbiotic traits were moderate (0.24–0.33), and the strong (r ≥ 0.97) genetic correlation between Shoot and Root DM indicated strong pleiotropy or close linkage. The moderate (r = 0.47) phenotypic correlation between Shoot DM under symbiosis vs. under N-supplementation suggested plant growth with mineral-N was not a strong predictor of symbiotic performance. At 5% among-family selection pressure, predicted genetic gains per selection cycle of 19 and 17% for symbiotic traits Shoot DM and Shoot SP, respectively, highlighted opportunities for improved early seedling establishment and growth under symbiosis. Single and multi-trait selection methods, including a Smith-Hazel index focussing on an ideotype of high Shoot DM and Shoot SP, showed commonality of top-ranked families among traits. This study provides a platform for proof-of-concept crosses to breed for enhanced seedling growth under Rhizobium symbiosis and is informative for other legume crops
Predictive glycaemic response of pasta enriched with juice, puree, and pomace from red cabbage and spinach
Get PDFThis study reports the digestibility and nutritional quality of pasta made from durum wheat semolina which was partially substituted by puree, juice or pomace from spinach and red cabbage. The results show that 10% substitution of semolina with red cabbage pomace and spinach pomace, 1% substitution of spinach juice, and 2% substitution of spinach puree significantly reduced the area under the curve of the in vitro starch digestion. This reduction was due to a combined effect of decreased starch content, increased dietary fibre content and inhibition of α-amylase caused by vegetable material addition. Total phenolic content (TPC) and antioxidant capacity increased significantly on raw, cooked and digested samples of vegetable fortified pasta compared to control. The β-carotene content of spinach pasta (raw, cooked, and digested) was also higher than that of control. At the 1% substitution level, the juice was more efficient in improving the antioxidant capacity of resultant pasta compared to puree or pomace