Classical Biological Control for the Protection of Natural Ecosystems.

Of the 70 cases of classical biological control for the protection of nature found in our review, there were fewer projects against insect targets (21) than against invasive plants (49), in part, because many insect biological control projects were carried out against agricultural pests, while nearly all projects against plants targeted invasive plants in natural ecosystems. Of 21 insect projects, 81% (17) provided benefits to protection of biodiversity, while 48% (10) protected products harvested from natural systems, and 5% (1) preserved ecosystem services, with many projects contributing to more than one goal. In contrast, of the 49 projects against invasive plants, 98% (48) provided benefits to protection of biodiversity, while 47% (23) protected products, and 25% (12) preserved ecosystem services, again with many projects contributing to several goals. We classified projects into complete control (pest generally no longer important), partial control (control in some areas but not others), and "in progress," for projects in development for which outcomes do not yet exist. For insects, of the 21 projects discussed, 59% (13) achieved complete control of the target pest, 18% (4) provided partial control, and 41% (9) are still in progress. By comparison, of the 49 invasive plant projects considered, 27% (13) achieved complete control, while 33% (16) provided partial control, and 47% (24) are still in progress. For both categories of pests, some projects' success ratings were scored twice when results varied by region. We found approximately twice as many projects directed against invasive plants than insects and that protection of biodiversity was the most frequent benefit of both insect and plant projects. Ecosystem service protection was provided in the fewest cases by either insect or plant biological control agents, but was more likely to be provided by projects directed against invasive plants, likely because of the strong effects plants exert on landscapes. Rates of complete success appeared to be higher for insect than plant targets (59% vs 27%), perhaps because most often herbivores gradually weaken, rather than outright kill, their hosts, which is not the case for natural enemies directed against pest insects. For both insect and plant biological control, nearly half of all projects reviewed were listed as currently in progress, suggesting that the use of biological control for the protection of wildlands is currently very active.

How can warren destruction by ripping control European wild rabbits (Oryctolagus cuniculus) on large properties in the Australian arid zone?

Context: For over 100 years, control efforts have been unable to stop rabbits causing damage to cattle production and native plants and animals on large properties in arid parts of Australia. Warren destruction by ripping has shown promise, but doubts about long-term success and the perceived expense of treating vast areas have led to this technique not being commonly used. Aims: This study measured the long-term reduction in rabbit activity and calculated the potential cost saving associated with treating just the areas where rabbits are believed to survive drought. Wealso considered whether ripping should be used in a full-scale rabbit control program on a property where rabbits have been exceptionally resilient to the influence of biological and other control measures. Methods: Rabbits were counted along spotlight transects before warrens were ripped and during the two years after ripping, in treated and untreated plots. Rabbit activity was recorded to determine the immediate and long-term impact of ripping, up to seven years after treatment. The costs of ripping warrens within different distances from drought refuge areas were calculated. Key results: Destroying rabbit warrens by ripping caused an immediate reduction in rabbit activity and there were still 98% fewer rabbits counted by spotlight in ripped plots five months after ripping. Seven years after ripping no active warrens were found in ripped plots, whereas 57% of warrens in unripped plots showed signs of rabbit activity. The cost of ripping only the areas where rabbits were likely to seek refuge from drought was calculated to be less than 4%of the cost of ripping all warrens on the property. Conclusions: Destroying rabbit warrens by ripping is a very effective way of reducing rabbit numbers on large properties in arid Australia. Ripping should commence in areas used by rabbits to survive drought. It is possible that no further ripping will be required. Implications: Strategic destruction of warrens in drought refuge areas could provide an alternative to biological control for managing rabbits on large properties in the Australian arid zone.

Commercial products from bio-active extractives in cypress milling residues.

Extractive components obtained from milling residues of white cypress were studied for chemical identity and bioactivity with a view to developing a commercial use for these components, thus increasing the value of the residues and improving the economics of cypress sawn wood production. Extracts obtained by solvent or steam extraction techniques from cypress sawdust were each fractionated by a range of techniques into groups of similar compounds. Crude extracts and fractions were screened against a range of agricultural pests and diseases, including two fungi, subterranean termites, fruit spotting bugs, two-spotted mites, thrips, heliothis, banana scab moths, silverleaf whiteflies, cattle tick adults and larvae, and ruminant gastrointestinal nematodes. Additional screening was undertaken where encouraging results were achieved, for two-spotted mites, thrips, silverleaf whiteflies, cattle tick adults and ruminant gastrointestinal nematodes. After considering degrees of efficacy against, and economic importance of, the agricultural pests, and likely production costs of extracts and fractions, the crude extract (oil) produced by steam distillation was chosen for further study against silverleaf whitefly. A useful degree of control was achievable when this oil was applied to tomato or eggplant at 0.1%, with much less harmful effects on a beneficial insect. Activity of the oil against silverleaf whitefly was undiminished 3.5 years after it was generated. There was little benefit from supplementing the extract with co-formulated paraffinic oil. From the steam distilled oil, fifty-five compounds were characterised, thirty-five compounds representing 92.478 % of the oil, with guaiol (20.8%) and citronellic acid (15.9%) most abundant. These two compounds, and a group of oxygenated compounds containing bulnesol and a range of eudesmols, were found to account for most of the activity against silverleaf whitefly. This application was recommended for first progression to commercialisation.

Dipping and jetting with tea tree (Melaleuca alternifolia) oil formulations control lice (Bovicola ovis) on sheep

The in vivo pediculicidal effectiveness of 1% and 2% formulations of tea tree (Melaleuca alternifolia) oil (TTO) against sheep chewing lice (Bovicola ovis) was tested in two pen studies. Immersion dipping of sheep shorn two weeks before treatment in both 1% and 2% formulations reduced lice to non detectable levels. No lice were found on any of the treated sheep despite careful inspection of at least 40 fleece partings per animal at 2, 6, 12 and 20 weeks after treatment. In the untreated sheep louse numbers increased from a mean (+/- SE) of 2.4 (+/- 0.7) per 10 cm fleece part at 2 weeks to 12.3 (+/- 4.2) per part at 20 weeks. Treatment of sheep with 6 months wool by jetting (high pressure spraying into the fleece) reduced louse numbers by 94% in comparison to controls at two weeks after treatment with both 1% and 2% TTO formulations. At 6 and 12 weeks after treatment reductions were 94% and 91% respectively with the 1% formulation and 78% and 84% respectively with the 2% formulation. TTO treatment also appeared to reduce wool damage in infested sheep. Laboratory studies indicated that tea tree oil 'stripped' from solution with a progressive reduction in concentration as well as volume as more wool was dipped, indicating that reinforcement of active ingredient would be required to maintain effectiveness when large numbers of sheep are treated. The results of these studies suggest significant potential for the development of ovine lousicides incorporating TTO. (C) 2012 Elsevier B.V. All rights reserved.

Field Assessments of Control Agents for Lesser Mealworm (Coleoptera: Tenebrionidae) Using Litter Sampling

Spinosad, diatomaceous earth, and cyfluthrin were assessed on two broiler farms at Gleneagle and Gatton in southeastern Queensland, Australia in 2004-2005 and 2007-2009, respectively to determine their effectiveness in controlling lesser mealworm, Alphitobius diaperinus (Panzer) (Coleoptera: Tenebrionidae). Insecticide treatments were applied mostly to earth or 'hard' cement floors of broiler houses before the placement of new bedding. Efficacy of each agent was assessed by regular sampling of litter and counting of immature stages and adult beetles, and comparing insect counts in treatments to counts in untreated houses. Generally, the lowest numbers of lesser mealworm were recorded in the house with hard floors, these numbers equalling the most effective spinosad applications. The most effective treatment was a strategic application of spinosad under feed supply lines on a hard floor. In compacted earth floor houses, mean numbers of lesser mealworms for two under-feed-line spinosad treatments (i.e., 2-m-wide application at 0.18 g of active insecticide (g [AI]) in 100-ml water/m(2), and 1-m-wide application at 0.11 g ([AI] in 33-ml water/m(2)), and an entire floor spinosad treatment (0.07 g [AI] in 86-ml water/m2) were significantly lower (i.e., better control) than those numbers for cyfluthrin, and no treatment (controls). The 1-m-wide under-feed-line treatment was the most cost-effective dose, providing similar control to the other two most effective spinosad treatments, but using less than half the active component per broiler house. No efficacy was demonstrated when spinosad was applied to the surface of bedding in relatively large volumes of water. All applications of diatomaceous earth, applied with and without spinosad, and cyfluthrin at the label rate of 0.02 g (AI)/100-ml water/m(2) showed no effect, with insect counts not significantly different to untreated controls. Overall, the results of this field assessment indicate that cyfluthrin (the Australian industry standard) and diatomaceous earth were ineffective on these two farms and that spinosad can be a viable alternative for broiler house use.

Evaluation of the use of prochloraz in the control of postharvest diseases of papaya in Australia

Prochloraz as Sportak at 450 g a.i./L is registered for the control of postharvest diseases in papaya in Australia. A project in far north Queensland in 2011, examined the use patterns of postharvest treatments, evaluated treatment dips and sprays for prochloraz concentrations and evaluated the efficacy of prochloraz at 0, 20, 40, 55 and 70 ml/100 L, fludioxonil as Scholar at 260 ml/100 L and azoxystrobin as Amistar at 50 ml/100 L. Results showed that packing shed use of Sportak varied with recycled and stored solutions showing a depletion of the active ingredient. Measured prochloraz in solution was highly pH dependent with nominal solution values only being measured when the pH was less than 3.0. In the fungicide efficacy trial Sportak at the label rate of 55 ml/100 L provided more effective disease control than fludioxonil and azoxystrobin. The trial also suggested that fruit from older trees showed a high degree of disease incidence relative to fruit from young trees.

Foliar herbicide control of sticky florestina (Florestina tripteris DC.)

Sticky florestina (Florestina tripteris DC.) is an annual exotic weed that has become naturalised near the townships of Tambo and Barcaldine in central western Queensland, Australia. Three experiments conducted near Barcaldine identified foliar herbicides effective in killing sticky florestina plants and in providing residual activity to reduce recruitment from the soil seed bank. An initial chemical screening experiment evaluated the efficacy of 28 herbicide treatments. The most promising herbicides were then further evaluated in two response-rate experiments. Overall, 2,4-D/picloram, aminopyralid/fluroxypyr, clopyralid, metsulfuron-methyl and triclopyr/picloram proved to be the most effective selective herbicides. Two of these, metsulfuron-methyl at 18 g active ingredient (a.i) ha–1 and 2,4-D + picloram at 900 g a.i. ha–1 + 225 g a.i. ha–1 have now been included in a minor use permit (PER11920) with the Australian Pesticides and Veterinary Medicines Authority (APVMA) for the control of sticky florestina in pasture, stock route, roadside and non-crop situations using both spot and boom-spray applications (APVMA 2010). The permit also allows the use of 2,4-D amine for the control of seedlings only.

Biological control of weeds in the 22 Pacific island countries and territories: current status and future prospects

Biological control of introduced weeds in the 22 Pacific island countries and territories (PICTs) began in 1911, with the lantana seed-feeding fly introduced into Fiji and New Caledonia from Hawaii. To date, a total of 62 agents have been deliberately introduced into the PICTs to control 21 weed species in 17 countries. A further two agents have spread naturally into the region. The general impact of the 36 biocontrol agents now established in the PICTs ranges from none to complete control of their target weed(s). Fiji has been most active in weed biocontrol, releasing 30 agents against 11 weed species. Papua New Guinea, Guam, and the Federated States of Micronesia have also been very active in weed biocontrol. For some weeds such as Lantana camara, agents have been released widely, and can now be found in 15 of the 21 PICTs in which the weed occurs. However, agents for other commonly found weeds, such as Sida acuta, have been released in only a few countries in which the weed is present. There are many safe and effective biocontrol agents already in the Pacific that could be utilised more widely, and highly effective agents that have been released elsewhere in the world that could be introduced following some additional host specificity testing. This paper discusses the current status of biological control efforts against introduced weeds in the 22 PICTs and reviews options that could be considered by countries wishing to initiate weed biological control programmes.