The leaf-feeding geometrid Isturgia disputaria (Guenee)-A potential biological control agent for prickly acacia, Vachellia nilotica subsp. indica (Benth.) Kyal. & Boatwr. (Mimosaceae) in Australia

Prickly acacia (Vachellia nilotica subsp. indica), a native multipurpose tree in India, is a weed of National significance, and a target for biological control in Australia. Based on plant genetic and climatic similarities, native range surveys for identifying potential biological control agents for prickly acacia were conducted in India during 2008-2011. In the survey leaf-feeding geometrid, Isturgia disputaria Guenee (syn. Tephrina pulinda), widespread in Tamil Nadu and Karnataka States, was prioritized as a potential biological control agent based on field host range, damage potential and no choice test on non target plant species. Though the field host range study exhibited that V. nilotica ssp. indica and V. nilotica ssp. tomentosa were the primary hosts for successful development of the insect, I. disputaria, replicated no - choice larval feeding and development tests conducted on cut foliage and live plants of nine non-target acacia test plant species in India revealed the larval feeding and development on three of the nine non-target acacia species, V. tortilis, V. planiferons and V. leucophloea in addition to the V. nilotica ssp. indica and V. nilotica ssp. tomentosa. However, the proportion of larvae developing into adults was higher on V. nilotica subsp. indica and V. nilotica subsp. tomentosa, with 90% and 80% of the larvae completing development, respectively. In contrast, the larval mortality was higher on V. tortilis (70%), V. leucophloea (90%) and V. planiferons (70%). The no-choice test results support the earlier host specificity test results of I. disputaria from Pakistan, Kenya and under quarantine in Australia. Contrasting results between field host range and host use pattern under no-choice conditions are discussed.

Managing resistance to chemical treatments in stored products pests

This review focuses on key trends in resistance to chemical treatments in stored product pests, and advances in resistance management, with an emphasis on resistance to the fumigant phosphine. Findings: Phosphine resistance continues to be a major concern. In particular, phosphine resistance in Cryptolestes ferrugineus has emerged as a serious issue, with some populations exhibiting the strongest level detected so far for this fumigant. In response, a 'quick knock down test' has been established to deliver industry and scientists 'same day' advice on the resistance status of field samples; sulfuryl fluoride is being developed as a 'resistance breaker' and phosphine dosages are being revised to manage this problem. There has been major progress in identifying the genes responsible for phosphine resistance and the development of molecular resistance diagnostics for key pests. Several studies on Rhyzopertha dominica have demonstrated that molecular screening can be used to determine the frequency of resistance alleles in samples collected from farm storages. Despite on-going research in several pests, there is no definitive answer to the question of whether there is a fitness cost associated phosphine resistance, with some studies showing a clear cost and others none. Evidence continues to emerge of resistance to grain protectants, including the juvenile hormone analogue methoprene. The development and adoption of spinosad, as a next generation 'green' treatment, and the use of protectant combinations provides opportunities to counter the problem of protectant resistance.Directions for future research: A uniform set of protocols should be developed for phosphine resistance detection for all major species. It should combine 'quick tests' and molecular diagnostics to be adopted internationally. Research is required on the establishment of a decision making system that integrates newly developed grain protectants and fumigants, other alternative control methods, as well as an accurate and rapid resistance detection system for early warning of the emergence of new resistances.

Chemical containment and eradication of screw− worm incursions in Australia

Screwworms are obligate, invasive parasites of warm-blooded animals. The female flies lay batches of eggs at the edge of wounds or other lesions. These eggs hatch to larvae or screw-worms which feed on affected animals for 6-7 days, burrowing deeply into subcutaneous tissues and causing severe trauma to animals, production loss and potentially death. Susceptible sites include wounds resulting from management practices such as castration, de-horning and ear tagging and lesions caused by the activities of other parasites such as buffalo flies and ticks. The navels of the new born and the vulval region of their mothers following parturition are highly susceptible and body orifices such as nose and ears are also frequent targets for ovipositing screwworm flies. The Old World screw-worm, Chrysomya bezziana (OWS) is considered one of the most serious exotic insect pest threatening Australia's livestock industries and is endemic in a number of our closest neighbouring countries. New World screwworm (NWS), Cochliomyia hominivorax, endemic to South America, has also entered Australia on at least 2 occasions. Many tropical and subtropical areas of Australia are suitable for the establishment of OWS and the potential range is expected to increase with climate change. The Australian screwworm preparedness strategy indicates a program of containment with chemical treatments followed by eradication of OWS using sterile male release and parasiticides. However, there is no longer an operational OWS sterile insect screw-worm facility anywhere in the world and establishing a large scale production facility would most optimistically take at least 2 years. In the interim, containment would be almost totally dependent on the availability of effective chemical controls. A review of chemical formulations available for potential use against OWS in Australia found that currently only one chemical, ivermectin administered by subcutaneous injection (s.c.) is registered for use against OWS and that many of the chemicals previously shown to be effective against OWS were no longer registered for animal use in Australia.18 From this review a number of Australian-registered chemicals were recommended as a priority for testing against OWS. The Australian Pesticides and Veterinary Medicines Authority (APVMA) can issue an emergency use permit for use of pesticides if they are registered in Australia for other animal uses and shown to be effective against OWS. This project tested the therapeutic and prophylactic efficacy of chemicals with potential for use in the treatment and control of OWS.

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.

Evaluation of chlorothalonil and paraffinic oil alone and in combinations with registered fungicides for the control of yellow Sigatoka (Mycosphaerella musicola) of bananas in Northern Queensland, Australia

The efficacy of chlorothalonil and paraffinic oil alone and in combinations with the registered fungicides propiconazole, tebuconazole, difenoconazole, epoxiconazole and pyrimethanil was evaluated in a field experiment over two cropping cycles in 2013 and 2014 in Northern Queensland, Australia, for control of yellow Sigatoka (caused by Mycosphaerella musicola) of banana. The predominantly applied by the banana industry treatment mancozeb with paraffinic oil was included for comparison. The results from the two cropping cycles suggested that all chemicals used with paraffinic oil were as effective or more effective than when applied with chlorothalonil, and chlorothalonil alone. Difenoconazole and epoxiconazole with paraffinic oil followed by propiconazole with paraffinic oil were the most effective treatments. Pyrimethanil and tebuconazole plus chlorothalonil were the least effective treatments. None of the chemical treatments was phytotoxic or reduced yield.

Area-wide releases and evaluation of the parasitoid Eretmocerus hayati(Hymenoptera:Aphelinidae) for silverleaf whitefly control

Silverleaf whitefly (SLW), Bemisia tabaci biotype B, is a major horticultural pest that costs Queensland vegetable growers millions of dollars in lost production and control measures each year. In the Bowen and Burdekin districts of North Queensland, the major cultivated SLW host crops are tomatoes, melons, green beans, pumpkins, eggplants, and cucumbers, which cover a total production area of approximately 6500 ha. Eretmocerus hayati, an effective SLW parasitoid, was imported into Australia by CSIRO in 2002 and released from quarantine in 2004. In 2006, DAFF established a mass-rearing unit for E. hayati at Bowen Research Station to provide E. hayati for release on vegetable farms within its SLW integrated pest management research program. A total of 1.3 million E. hayati were released over three seasons on 34 vegetable farms in the Bowen and Burdekin districts (October 2006 to December 2008). Post-release samplings were conducted across the release area over this time period with parasitism levels recorded in tomatoes, melons, beans, eggplants, pumpkins, and various SLW weed hosts. Sample data show that E. hayati established at most release sites as well as some non-release sites, indicating natural spread. Overall results from these three years of evaluation clearly demonstrated that E hayati releases played a significant role in SLW control. In most crops sampled, E hayati exerted between 30 and 80% parasitism. Even in regularly sprayed crops, such as tomato and eggplant, E. hayati was able to achieve an overall average parasitism of 45%.