Silver Leaf Whitefly Assessment Tour (27-28/11/06)
Angas Swann (Bayer Crop Science) Stephen Moore (E. E. Muir & Sons) Bayer Lab Brisbane (Leon Radunz, Chris):
• Testing for imidacliprid metabolites is a lot harder but is a more accurate measure. • The HPLC machine costs $450,000. • Samples should be delivered in foam boxes with dry ice in them. Plants can still metabolize chemicals after picking. • Lab was very clean with a lot of hi tech equipment. • Confidor residue testing is difficult because Confidor breaks down into different metabolites. Bayer is probably the only laboratory to have the standards and equipment required to test the levels accurately. • Testing all the metabolites is important as the MRL is based on all constituents (ie. Imidacloprid and metabolites). 
Some of the equipment used in MRL Testing SLWF Update: (Chris Themsen)
• Pest then progressed into southern QLD and 2 years ago was found in Carnarvon WA. Has also been found in glass houses in Tatura VIC. • High reproduction rate, up to 10 generations per year in hot climates. • Wings are up write and gapped whilst resting. The best time to monitor is in the morning when it is cool and the sun is not too hot. • Eggs are laid singularly or clumps, not in an arc like other white flys. Always on the undersides of the leaf. • Farmers are not using chemicals off label. • Good results with Confidor, over the top, 50 per cent less after each spray. • Natrosope, malaises, used as another control option. • Pressure is dropping in Bundaberg due to good management including confidor use under the crop, other chemicals over the top, having a crop free zone, and other cultural practices. • Sweet potato is a major host, although does not sustain any damage. • Silverleaf whitefly (Bemisia tabaci) is a native of Australia but the Bemisia tabaci Biotype B is the introduced species that is a problem pest. These two types can only be identified as different using DNA techniques. It is possible that these two get mis-identified but it is possible to tell the difference when the Bemisia tabaci Biotype B is present. • Up to 80% control of SLWF applied foliar with the first application. 50 per cent less control with each following spray. • Natrosope, used 2 times a week gave good control but can have a detrimental affect on the plant health. Edosulfan,Bullock and pyrethrum had some effect on the SLWF Endosulfan and natrasoap worked better than each product on their own. 
Angus Swann & Chris Thempson (Bayer CropScience), Mat Newland (Boomaroo Nurseries) & Steven Moore (E.E.Muir & Sons) (Taking Picture), discuss the latest developments of SLWF and plan for days activities over breakfast. (Bundaburg) Infield identification (Darren Zunker):Farm Visit - Sweet potato, pumpkin and sugar cane.
• Adults congregate on the underside of the leaf. • Eggs are laid on the underside of the leaf. • Nymphs are visible with a hand lenses and are a yellow-green colour. • Parasitized nymphs are clear. • When walking through the crop adults will freely fly up from the crop. • Pest Migrated from neighbors farm. • Sweet potato can withstand very high numbers of SLWF because the sweet potato will shoot new stems and leaves after being damaged. The pumpkins after SLWF feeding develop silvery leaves that no longer photosynthesis. With the loss of leaves the flowers abort and yields are reduced significantly. • The overall SLWF pressure has dropped in Bundaberg because the natural predators and introduced predator have helped establish an equilibrium. • Pumpkin is a problem and monitoring is used to determine what products to use. Molasses is used at 5-10L /hectare to stick the adult whitefly. • Confidor moves into the youngest leaves with the growing point so it is important to spray the oldest leaves. Nitofol will flare SLWF numbers. Lorsban keeps numbers in check but no significant control. 
Angus Swann & Chris Thempson (Bayer CropScience), Mat Newland (Boomaroo Nurseries) & Steven Moore (E.E.Muir & Sons) talk with Darren Zunker about his experiences with SLWF. 
A view of the pest Crop Tech (Mal Frick):
• When finish picking the crop an application of DC-Tron and spray seed is used to desecrate the crop to try and reduce numbers, this also helps to reduce Thrip numbers. Things to Consider when preparing for SLWF:
• Griffith in NSW will be a problem before Victoria get it. • Natural predators can give up to 30% control in good conditions. • It is a numbers game, need to reduce heavy infestations. • The biggest problem is that the pest will come from someone else. (Asian Growers in the Lara Region.) • Green house growers such as Vietnamese growers close to Boomaroo need to be monitored and offer assistance to them if required. • 8 life cycles a year in Bundaberg. • 3 generations maybe in Vic (guess). • Hot and dry conditions are favorable for SLWF (northern VIC and southern NSW are our biggest threat). • Initiation discussions with APVMA Allan Norden/Peter Dal santo to get an emergency permit in place before pest is visible in Victoria. • Admiral and Chess are options for emergency use in an over the top application. • Telstar can be used as a clean up and end of harvest only. • Unlikely to spread outside green house production in Victoria. • Dimethoate must be sprayed to send produce interstate from QLD. QLD DPI (Ian Kay)
• May be an issue in Glass House production, especially climate controlled houses. • A whole management practice must be adopted to control the pest. • Monitoring on a regular basis must be done. Use yellow traps. • Speak to VIC DPI to help with plan. • Subra ?? in Bowen is the SLWF expert with the QLD DPI. • TYLCV spread by adults only and it is most likely not passed on to nymphs. • Cannot see SLWF eggs on tomatoes due to the upright hairs on tomato plants. Brassica crops are the easiest plants to see SLWF eggs on due to the waxy surfaces. • No reported case as being a problem on lettuce but it can be present and a contaminant. SP Exports (Damien and Emma):
• 40ml / 1000 plants rate used on their seedlings. This is the first year of use. • 14 weeks control is being noticed in the field. Only Grower in QLD to use Confidor drenched seedlings, with great results. • Dispatch coordination from Withcottt nursery was very important to ensure all Confidor drenched seedlings were planted as soon as possible after delivery. • The right sized plants needed to be delivered or the crop would struggle to grow. • Very happy now the teething problems have been fixed. • Dispatch coordination from Withcottt nursery was very important to ensure all Confidor drenched seedlings were planted as soon as possible after delivery. • The risk of TYLCV was the driving factor in deciding to use confidor seedling drench. • SP Exports monitor crops thoroughly, • Oil based product used if low pressure, • With increasing pressure Chess is used. • As a last resort Admiral is used. • Crops are sprayed and ploughed when finished. 
SP Exports tomato harvestors 
SP Exports are on track with SLWF & TYLF , growing excellent product Take away messages from the trip:
• Farm Hygiene is paramount. • The pest is unlikely to reach southern VIC but could be an issue in Northern VIC and Southern NSW. • Glasshouses will be hotspots in Victoria. Must keep an eye on our Asian neighbors. • Contamination to Boomaroo is most likely from close glass houses and home gardens. • The DPI in Victoria needs to be contacted about the possible issue. • An Emergency Use Permit needs to be built. Peter Dal Santo can provide an emergency for use permit within 2 hours given formal notification. • Confidor is working well on tomatoes but it is only part of the total management solution. • Seedling drench is the preferred option for treatment. 
Angus Swann & Chris Thempson (Bayer CropScience), Mat Newland (Boomaroo Nurseries) & Steven Moore (E.E.Muir & Sons) at the end of the day, very satisfied with the information gained on this valuable Visit to QLD. |
|
| © Boomaroo Nurseries 2007 Sitemap | |