Pesticide residues in food - acute dietary exposure

Consumer risk assessment is a crucial step in the regulatory approval of pesticide use on food crops. Recently, an additional hurdle has been added to the formal consumer risk assessment process with the introduction of short-term intake or exposure assessment and a comparable short-term toxicity reference, the acute reference dose. Exposure to residues during one meal or over one day is important for short-term or acute intake. Exposure in the short term can be substantially higher than average because the consumption of a food on a single occasion can be very large compared with typical long-term or mean consumption and the food may have a much larger residue than average. Furthermore, the residue level in a single unit of a fruit or vegetable may be higher by a factor (defined as the variability factor, which we have shown to be typically ×3 for the 97.5th percentile unit) than the average residue in the lot. Available marketplace data and supervised residue trial data are examined in an investigation of the variability of residues in units of fruit and vegetables. A method is described for estimating the 97.5th percentile value from sets of unit residue data. Variability appears to be generally independent of the pesticide, the crop, crop unit size and the residue level. The deposition of pesticide on the individual unit during application is probably the most significant factor. The diets used in the calculations ideally come from individual and household surveys with enough consumers of each specific food to determine large portion sizes. The diets should distinguish the different forms of a food consumed, eg canned, frozen or fresh, because the residue levels associated with the different forms may be quite different. Dietary intakes may be calculated by a deterministic method or a probabilistic method. In the deterministic method the intake is estimated with the assumptions of large portion consumption of a ‘high residue’ food (high residue in the sense that the pesticide was used at the highest recommended label rate, the crop was harvested at the smallest interval after treatment and the residue in the edible portion was the highest found in any of the supervised trials in line with these use conditions). The deterministic calculation also includes a variability factor for those foods consumed as units (eg apples, carrots) to allow for the elevated residue in some single units which may not be seen in composited samples. In the probabilistic method the distribution of dietary consumption and the distribution of possible residues are combined in repeated probabilistic calculations to yield a distribution of possible residue intakes. Additional information such as percentage commodity treated and combination of residues from multiple commodities may be incorporated into probabilistic calculations. The IUPAC Advisory Committee on Crop Protection Chemistry has made 11 recommendations relating to acute dietary exposure.

Resistance of selected strawberry cultivars to root-knot nematode species (Meloidogyne spp.)

Strawberry runner production areas in Queensland are assessed for the presence of Pratylenchus vulnus (lesion nematode) and Meloidogyne hapla (root-knot nematode) as part of the approval process for sites used in runner production under the approved runner scheme. M. hapla is known to infest strawberry. The ability of three other Meloidogyne species occurring in Queensland to infest this host was investigated. The species M. arenaria, M. incognita and M. javanica, in addition to M. hapla, were able to reproduce on strawberry roots of the cultivar 'Joy', which sustained higher nematode reproduction rates than 'Jewel' and 'Sweet Charlie'. The ability of species other than M. hapla to infest strawberry needs to be recognised in site selection for runner production, and in screening cultivars for resistance to nematodes.

Environmental regulation in the pork producing industry - bring on the research!

Over the last 20 years, environmental management in Queensland has moved from the policy backwaters of government to the front line of operations by way of regulatory enforcement, industry programs and incentives. When the new Queensland Environmental Protection Act 1994 (EPA) came into effect, the business of environmental management has become a central feature of urban and rural development activity. The concept of environmentally sustainable development (ESD), has given life to the precautionary principle as a way for planners and regulators to place relevant controls on development. The planning, development and operation of pig farming systems has been effected by the new regulatory framework. Ever more definitive standards and approval permits have emerged which endeavour to achieve ESD. With these modern planning instruments in place, rural industry sectors have become, quite legitimately, concerned about future opportunities for research and innovation. This paper asserts that the capacity to engage in research and to achieve innovation in the pork producing industry is not hindered by Queensland environmental regulation frameworks. However, in order for research and innovation to prosper within these frameworks, some protocols need to be followed by the industry. What is at stake is community confidence.

A review of Australian classical biological control of weeds programs and research activities over the past 12 years

Considerable progress has been made towards the successful classical biological control of many of Australia’s exotic weeds over the past decade. Some 43 new arthropod or pathogen agents were released in 19 projects. Effective biological control was achieved in several projects with the outstanding successes being the control of rubber vine, Cryptostegia grandiflora, and bridal creeper, Asparagus asparagoides. Significant developments also occurred in target prioritization, procedures for target and agent approval, funding, infrastructure and cooperation between agencies. Scientific developments included greater emphasis on climate matching, plant and agent phylogeny, molecular diagnostics, agent prioritization and agent evaluation.

GM solutions to root diseases of cereals - A situation analysis and business case

Root disease causes about $503 million in losses annually to Australia's wheat and barley industries. Because of these large losses and in many cases the difficulty in reducing these losses through breeding or management, root diseases are candidates for solutions through genetic modification (GM). Through an extensive review of the scientific literature and patents, a range of approaches to GM solutions to root diseases are critically discussed. Given the high cost of regulatory approval for GM crops and a complex intellectual property (IP) landscape, it is likely that research in this area will be done in collaboration with international partners.

The Jewel Beetle (Hylaeogena jureceki); a new biocontrol for cat’s claw creeper (Dolichandra unguis-cati) in Queensland

Cat’s claw creeper (Dolichandra unguis-cati (Bignoniaceae) is a serious environmental weed in Queensland and New South Wales. It presents a threat to riparian and rainforest ecosystems and is often found in inaccessible locations that are not suitable for chemical or physical control methods. This makes biological control an important tool for managing this weed. The jewel beetle Hylaeo¬gena jureceki was approved for release in Australia in May 2012. Since approval, approximately 35,000 insects have been released at 53 sites. Multiple and single releases have been made at sites with the number of insects released ranging from 20 to 1590. Post-release monitoring before and after winter found the beetle persisting at 73% of release sites in southeast Queensland. Within the release sites, the beetle appears to disperse widely, up to 100 m over a 15 month period. Based on these early field results, it appears that the beetle will establish and spread in Queensland and New South Wales. In addition to direct field releases, the beetle has been supplied to various community and Landcare groups for breeding and field release. This will hasten the spread of the insect to a wider area. It is expected that the jewel beetle will complement the leaf-sucking tingid (Carvalhotingis visenda) and leaf-tying moth (Hypocosmia pyrochroma) that were released in 2007.

The host specificity and climatic suitability of the gall flyCecidochares connexa(Diptera: Tephritidae), a potential biological control agent for Chromolaena odorata(Asteraceae) in Australia

The gall fly Cecidochares connexa (Diptera: Tephritidae) is a potential biological control agent for Chromolaena odorata in Australia. Its host specificity was determined against 18 species in the tribe Eupatorieae (Family Asteraceae) in which C. odorata belongs, in quarantine in Brisbane, Australia. Oviposition occurred and flies developed on only C. odorata and Praxelis clematidea, both of which are in the subtribe Praxelinae. P. clematidea is considered a weed outside tropical America. In both multiple-species-minus-C. odorata choice tests and single-species no-choice tests, the mean number of galls/plant was significantly greater on C. odorata (48 and 41, respectively) than on P. clematidea (2 and 9, respectively). There were also significantly more adults emerging from C. odorata (mean 129 and 169, respectively) in the two types of tests than from P. clematidea (1 and 8, respectively). Paired choice, multiple generation (continuation) and time dependent tests further clarified the extent that C. connexa could develop on P. clematidea. In these tests, the mean number of galls formed and the mean number of emerging adults were consistently less for P. clematidea than C. odorata and populations of C. connexa could not be maintained on P. clematidea. Galls were not seen on any other plant species tested. This study supports the results of host specificity testing conducted in seven other countries and confirms that C. connexa poses little risk to other plant species in Australia. C. connexa has been released in 10 countries and an application seeking approval to release in Australia has been submitted to the Australian Government.