Evaluation of fixed sample-size plans for Plutella xylostella (Lepidoptera: Plutellidae) on broccoli crops in Australia

Fixed sample-size plans for monitoring Plutella xylostella (L.) (Lepidoptera: Plutellidae) on broccoli and other Brassica vegetable crops are popular in Australia for their simplicity and ease of application. But the sample sizes used are often small, ≈10–25 plants per crop, and it may be that they fail to provide sufficient information upon which to base pest control decisions. We tested the performance of seven fixed sample-size plans (10, 15, 20, 30, 35, 40, and 45 plants) by resampling a large data set on P. xylostella in commercial broccoli crops. For each sample size, enumerative and presence-absence plans were assessed. The precision of the plans was assessed in terms of the ratio of the standard error to the mean; and at least 45 and 35 samples were necessary for the enumerative and presence-absence plans, respectively, to attain the generally accepted benchmark of ≤0.3. Sample sizes of 10–20 were highly imprecise. We also assessed the consequences of classifications based on action thresholds (ATs) of 0.2 and 0.8 larvae per plant for the enumerative case, and 0.15 and 0.45 proportion of plants of infested for the presence-absence case. Operating characteristic curves and investigations of the frequency of correct decisions suggest improvements in the performance of plans with increased sample size. In both the enumerative and presence-absence cases, the proportion of incorrect decisions was much higher for the lower of the two ATs assessed, and type II errors (i.e., failure to suggest pest control upon the AT is exceeded) generally accounted for the majority of this error. Type II errors are the most significant from a producer’s standpoint. Further consideration is necessary to determine what is an acceptable type II error rate.

Studies on physiologic specialisation of albugo candida causing white blister on broccoli in Victoria

White blister caused by oomycete Albugo candida (Pers. Ex. Lev.) Kuntze, (AC), is an important disease affecting many cruciferous hosts, including vegetable brassicas. The outbreaks of white blister in broccoli and cauliflower crops (Brassica oleracea var. italica and var. botrytis) in Southern Australia in the last three years led to restrictions on movement of fresh produce and seedlings from the disease-affected areas. Current classification of AC races is based on physiologic specialisation of this pathogen. Race 9 has been identified to cause white blister on B. oleracea in the USA. We report on specialisation of AC causing disease in Victorian broccoli crops and the use of molecular tools for the separation of AC races. In a glasshouse, 12 Brassicaceae species/varieties replicated 6 times, were inoculated twice at the fully developed cotyledon stage with a distilled water suspension of zoosporangia (1x104 per ml) collected from a single broccoli leaf. Two weeks after inoculation the incidence of white blister on cotyledons and seedling leaves of cauliflower, broccoli, black mustard and Indian mustard was 79.7, 78.4, 73.7 and 6.9% respectively. Cabbage plants were symptomless indicating that further specialisation of the pathogen may have occurred in Australia. High disease incidence among black mustard plants shows that the Australian isolate differs from overseas AC race 9. The interaction of a number of B. oleracea varieties to a range of AC isolates from various hosts will be investigated. Degenerate primers are now being used to amplify actin and β-tubulin genes to identify race specific polymorphisms in AC isolates from three different hosts (wild radish, Chinese cabbage, and broccoli). Differing PCR amplification efficiencies from broccoli and wild radish isolates using degenerate actin primers indicates sequence differences in the two isolates. The fragments are now being cloned and sequenced for race comparison.

The use of table and cooking salt in a sample of Australian adults

Dietary sodium, the major source being salt, is associated with hypertension. Australian adults consume more than the recommended amount of salt and approximately 15% of dietary sodium comes from salt added at the table and during cooking. Objective: To determine the frequency of and the demographic characteristics associated with discretionary salt use. Design: A cross sectional survey conducted in shopping centres within Metropolitan Melbourne. Participants completed a questionnaire assessing discretionary salt use and attitudes to salt intake. Outcomes: Four hundred and seventy four surveys were collected (65% female, 77% Caucasian, 64% holding a university qualification). Eighty nine percent of respondents were classified as salt users and 11% as non-salt users. Of the salt users 52% reported that they always or sometimes add salt during cooking and at the table. Those of Asian descent and younger respondents aged 18-24 years were more likely to be salt users (chi2=12.3, df=2, p<0.001; chi2=19.2, df=5, p<0.01). Conclusion: Discretionary salt use remains high. To successfully reduce population dietary salt intake public health campaigns are urgently required and need to include consumer advice to reduce discretionary salt use, whilst reducing the salt added to processed foods. Such campaigns should include younger age groups and should be appropriate for all ethnic backgrounds to raise the awareness of the risks of a high salt diet on health.

Volunteering in a school kitchen garden program : cooking up confidence, capabilities and connections!

This paper reports on the evaluation of a kitchen garden program in primary schools in Victoria, Australia. It focuses on the motivations, impacts, and issues associated with volunteering in the program. The study revealed that volunteers are drawn from a range of sources, including: families of current and former students, former teachers, local residents, clients of aged care and/or disability services, other schools and communities, local universities, community organizations, the community services sector, and the corporate sector. Benefits to volunteers included: opportunities to use time productively, an increased sense of belonging, learning opportunities, and an increased sense of self-worth and enjoyment. For schools, volunteers enhanced engagement between the school and the local community, enabled them to engage more effectively with hard to reach groups, and increased student engagement. In addition, the involvement of volunteers improved the sustainability of the program, improved communication between teachers and families of students from minority ethnic groups, and gave students the chance to relate to new people, to learn from their experience and to have fun in working with the volunteers. Perhaps the most telling benefits to flow both to students and to volunteers were not the “three Rs—reading, w’riting and a’rithmetic” but the three Cs—confidence, capabilities, and connections. However, a clearly identified issue was the importance of matching volunteers’ motivations and needs with the roles they play to sustain current levels of volunteering and, therefore, the program itself.

Salicylic acid suppression of clubroot in broccoli (Brassicae oleracea var. italica) caused by the obligate biotroph Plasmodiophora brassicae

The obligate soil-borne biotroph Plasmodiophora brassicae has a significant economic impact on Brassicaceae crops. The pathogen severely disrupts the roots by inducing the production of galls which leads to malformation and reduced growth of the roots and a reduced ability to take up water and nutrients. Control of P. brassicae is difficult because it has a number of survival and dissemination strategies that involve both motile and resting stages that need to be targeted by any control agent. We investigated, under controlled conditions and in glasshouse and field experiments, the potential of salicylic acid (SA), a key phytohormone, that is required for defence against certain biotic and abiotic stresses, to reduce infection by P. brassicae in broccoli (Brassicae oleracea var. italica). Under controlled conditions in a growth cabinet exogenous application of SA to roots resulted in its transport systemically to the leaves where it promoted the up-regulation of the pathogenesis related genes PR-1 and PR-2 in an SAR-like response as early as 24 h post-treatment. Concentrations of SA >20 mM reduced significantly both shoot and root weights when applied exogenously but lower concentrations had little measureable effect on plant growth. When SA was applied to plants above 5 mM there was a significant reduction (25-65 %) in gall formation 6 weeks post-inoculation with P. brassicae, indicating that the pathogen was being controlled by the addition of SA. A combination of SA and JA was also shown to reduce severity (25-35 %) of disease associated with P. brassicae. These findings indicate that there may be SA inducible mechanisms in B. oleracea that if fine-tuned could provide enhanced resistance to clubroot disease.

Effect of sorghum flour addition on in vitro starch digestibility, cooking quality and consumer acceptability of durum wheat pasta

Whole grain sorghum is a valuable source of resistant starch and polyphenolic antioxidants and its addition into staple food like pasta may reduce the starch digestibility. However, incorporating nondurum wheat materials into pasta provides a challenge in terms of maintaining cooking quality and consumer acceptability. Pasta was prepared from 100% durum wheat semolina (DWS) as control or by replacing DWS with either wholegrain red sorghum flour (RSF) or white sorghum flour (WSF) each at 20%, 30%, and 40% incorporation levels, following a laboratory-scale procedure. Pasta samples were evaluated for proximate composition, in vitro starch digestibility, cooking quality, and consumer acceptability. The addition of both RSF and WSF lowered the extent of in vitro starch digestion at all substitution levels compared to the control pasta. The rapidly digestible starch was lowered in all the sorghum-containing pastas compared to the control pasta. Neither RSF or WSF addition affected the pasta quality attributes (water absorption, swelling index, dry matter, adhesiveness, cohesiveness, and springiness), except color and hardness which were negatively affected. Consumer sensory results indicated that pasta samples containing 20% and 30% RSF or WSF had acceptable palatability based on meeting one or both of the preset acceptability criteria. It is concluded that the addition of wholegrain sorghum flour to pasta at 30% incorporation level is possible to reduce starch digestibility, while maintaining adequate cooking quality and consumer acceptability.

Modern kitchens : and what their owners say of the speed, comfort, economy and convenience of electric cooking

"In the pages of this booklet we have given you actual quotations from a few of the many letters which we have recived from delighted users of Electric Ranges." -- blurb.

Jamie's Ministry of Food: quasi-experimental evaluation of immediate and sustained impacts of a cooking skills program in Australia

To evaluate the immediate and sustained effectiveness of the first Jamie's Ministry of Food Program in Australia on individuals' cooking confidence and positive cooking/eating behaviours.

Wider impacts of a 10-week community cooking skills program - Jamie's Ministry of Food, Australia

Jamie's Ministry of Food (JMoF) Australia is a 10-week community-based cooking skills program which is primarily aimed at increasing cooking skills and confidence and the promotion of eating a more nutritious diet. However, it is likely that the program influences many pathways to behaviour change. This paper explores whether JMoF impacted on known precursors to healthy cooking and eating (such as attitudes, knowledge, beliefs, cooking enjoyment and satisfaction and food purchasing behaviour) and whether there are additional social and health benefits which arise from program participation.