Ground Cover Supplement : GC Supplement - Integrated pest management
19 INTEGRATED PEST MANAGEMENT GROUND COVER Repeat sampling over 12 days Before any decision is made on the need to spray, at least four estimates of larval density should be made over 12 days. On each occasion, at least five 10-sweep samples should be taken from throughout the crop. If average numbers remain constant, low or decrease over the 12 days, insecticide applications will not result in an economic return. Conversely, if grub numbers steadily increase over 50 per 10 sweeps, insecticide application could be beneficial. Approximately four days after an insecticide application, the same 12-day monitoring process should be applied. Growers should expect to find DBM because, unlike other insect pests, complete elimination of an infestation cannot be expected. Monitoring after a pesticide application provides information on the level of success and the need for further controls. In trials in 2005, DBM numbers in unsprayed plots increased 3.5-fold over five weeks. A spray application in mid-August had minimal impact on the damage caused by DBM. In comparison, an early program of two spray applications three days apart resulted in a much greater control of grubs and reduction in yield loss. Grub numbers fell to less than 10 grubs per 10 sweeps and peaked one month later at 150 grubs per 10 sweeps. Untreated plots peaked at nearly 300 grubs per 10 sweeps. In the aforementioned trials, registered insecticides were applied using best-practice application techniques established by the trial program. Our trials established that aerial and ground-based applications are equally effective at providing water rates, and droplet size achieved good leaf coverage and spray penetration to the lower leaves of plants, with minimal off-target loss of the active ingredient. In our trials this was achieved by medium to coarse droplets applied by either ground rigs (flat fan 11015 nozzles) with a water volume of about 50 litres per hectare, or aerially (CP90 nozzles) with 30L/ha. The proportion of DBM found in each section of the canola plant showed minimal change during the day (Table 2). On average, 20 per cent of DBM grubs were found in the lower part of the canopy, emphasising the importance of chemical penetration. A considerable difference was found in the proportion of DBM killed by different insecticides. Of the six most effective treatments out of the 17 tested, only Bacillus thuringiensis (Bt) is registered for use against DBM in canola in WA. The registered chemicals, except Bt, were cheaper, but less effective. Trials found no improvement in DBM control if high rates of these cheaper registered chemicals were applied. However, multiple applications, four to five days apart, could give economic control. □ GRDC Research Code DAW00041 More information: Kevin Walden, senior research officer, DAFWA, 08 9956 8539, firstname.lastname@example.org IPM IN ACTION Rapid response helps IPM Growers, agronomists and researchers in all states now have free online access to timely pest information. Links to these sites are available at www.grdc.com.au/pestlinks (online in Autumn 2008) Western Australia -- PestFax As its name suggests this service started as a fax, but it is now a weekly email, distributed to subscribers during the growing season. PestFax is an informative and interactive reporting service on diseases and pests threatening crops and pastures throughout the grainbelt of WA. Editor Peter Mangano collates the news, risk alerts, current information and advice supplied by growers, agronomists and researchers. To subscribe or see back copies of PestFax go to the Department of Agriculture and Food, WA, website (www.agric.wa.gov.au). Victoria, Tasmania, southern NSW -- PestFacts Since its launch in 2007, PestFacts has encouraged and developed a good rapport with agronomists, consultants, agribusiness staff, growers and researchers, leading to timely reporting of pest incidences, effective controls and information about relevant research findings. This free service, coordinated by Paul Umina from CESAR, issues warnings/ reminders for a range of invertebrate pests of all broadacre crops, including pulses, oilseeds, cereals and fodder crops, keeping the industry informed about invertebrate- pest-related issues and solutions as they emerge during the growing season. To subscribe, contact Dr Paul Umina, 03 8344 2522, email@example.com, or visit http://cesarconsultants.com.au/services/pest-facts.html. South Australia, western Victoria -- PestFacts PestFacts is a service providing updates throughout the growing season on an "as- needed" basis of the latest information on invertebrate pests in broadacre crops in SA and western Victoria. This free email service is coordinated by Ken Henry and Judy Bellati of the South Australian Research and Development Institute. To subscribe, please email Ken Henry, firstname.lastname@example.org. Queensland, northern NSW -- The Beat Sheet The Beat Sheet is a blog about insect pest management issues relevant to Australia's northern grain region. This team blog is updated by entomologists from the Queensland Department of Primary Industries and Fisheries (QDPI&F), chiefly Dave Murray (a.k.a. 'Big Bug') and Melina Miles (a.k.a. 'Bug Lady'). It contains timely information and advice, high-quality images of pests and damage symptoms, and links to other information sources. An excellent example of the value of the blog was the team's response to an outbreak of Rutherglen bug (RGB) in sorghum. There was little published information on the control of RGB in sorghum, but the team evaluated the situation and provided growers with practical guidance on managing this problem. Visit www.thebeatsheet-ipmnews.blogspot.com. All states Timerite® (www.timerite.com.au) is a web-based resource that predicts the best date for spraying in spring to achieve optimal control of redlegged earth mite (RLEM) the following autumn. Growers can download the RLEM pasture check, RLEM risk calculator and the Timerite® spray date for their property from this website. A new part of the GRDC website, Pest Links (www.grdc.com.au/pestlinks), is due online in autumn 2008. Publications relating to IPM can also be sourced from state departments of primary industries, Pulse Australia and Ground Cover Direct.
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