An excuse of "bad weather" was given for delay but no rain was recorded at the optimum spraying time.
Gai Marshall attended a recent Field Day at Andrew Weiderman's property and data has been obtained and analysed from the "2008 Better Canola Victorian Demonstration" pamphlet plus followed up with email confirmation of accuracy with the contact person listed.
1. Weed control:
Site was chemical fallow in 2007.
All plots were treated with 1.5l/ha Trifluralin prior to sowing (as per recommendation for RR varieties)
Canola sown May 9th.
Roundup Ready - Herbicide recommendations were followed well. Glyphosate was applied on time when weeds were manageable (26 June when ryegrass was 2-4leaf, musk 5cm, vetch 2 node and hogweed 2 leaf.) Report states RR "had the advantage over the other two systems of smaller weed size."
Victorian Field Trial on 31st October. 2008 Field Day comment by Kate Burke - John Stuchberry & Associates "good control of musk, Struggled on hogweed and vetch. 2nd germination of weeds – cotaledon and hogweed.
Triazine tolerant - Herbicide recommendations were not followed. No knockdown was used. No pre-emergent triazine was used (essential to the success of TT varieties). A half rate (1.1kg/ha) of Atrazine was applied late when weeds were too advanced with Select @ 500ml/ha, Uptake 1% and Lontrel @100ml/ha (district practise is 150ml/ha for Lontrel) (6 July when ryegrass was 4-6 leaf, musk 10cm, vetch 4 node and hogweed 4 leaf.)
Clearfield - Herbicide recommendations were not followed. No knockdown was used. Intervix @ 550ml/ha was applied far too late when ryegrass was outside label recommendations with 70ml/ha of Lontrel and Hasten @ 0.5% (district practise would be to add Select but it was not used). (15 July when ryegrass was late tillering, musk 20cm, vetch 6-8 node and hogweed 4 leaf.).
Victorian Field Trial on 31st October. 2008 Field Day Comment: Kate Burke - John Stuchberry & Associates There was "ryegrass survivors" (not surprising considering the size of the ryegrass when it was sprayed)
Label recommendations for Triazine application on TT varieties (using 4Farmers Atrazine 900 WG label as referred to from APVMA website)
Maximum 2.7kg/ha consisting of:
Pre-emergent: 1.1 - 2.2kg/ha
Post emergent: 0.5-1.1kg/ha. Ryegrass control 1-2 leaf stage only.
Apply second application within one month of planting.
Note:
- No pre-emergent was applied
- Post emergent application was to be applied within one month of planting (9th May) but was not applied until (6 July) which is almost a month late.
- Ryegrass size exceeds label recommendation for control.
Industry best practise
GRDC Better Canola Agronomy report
- Generally glyphosate as knockdown with trifluralin incorporated for residual grass control
- Simazine pre-emergent (half rate of 2l/ha or 1.1kg/ha)
- Atrazine post emergent (half rate of 2l/ha or 1.1kg/ha)
- Selectives as required
** These trials deliberately ignored the standard weed control used for non-GM varieties. No knockdown herbicide was used and no triazine was applied when sowing. TT varieties only received a half dose of Atrazine well after it should have been applied when the weeds were twice the size as the weeds in RR crops when they received their treatment. The delay in chemical application in Clearfield varieties resulted in weeds being 4 times the size of weeds when RR varieties were treated. Both Triazine Tolerant and Clearfield varieties were treated past label recommendations when weeds were too large for chemicals to be effective. ***
Andrew Weiderman claims rain was the reason for delay in spraying but there was no rain recorded during the optimum spraying window. For TT varieties, spraying should have occurred before June 9th when the Australian Oilseeds Federation webstie states there was no rain.
Rainfall record on virtual canola crop on australian Oilseeds Federation website:
9-11 June = 25mm
RR crop sprayed 23 June but TT and Clearfield NOT SPRAYED
1 July - 8mm
2-3 July - 15mm
After 3 July - 36mm
TT canola sprayed 6 July
Clearfield canola sprayed 15 July
After 20 July - 13mm
2nd June: There has been no rain over the past week. The crop is still at the cotyledon stage, with some plants at the first leaf stage.
18 June: The crop is now at the 4-5 leaf stage and looking excellent, following 25 mm rain between 9-11 June. The variety is markedly more vigorous than some triazine tolerant varieties sown as a demonstration on the same day in the same paddock. A small area near the fenceline has been infested with redlegged earthmite, which will be controlled next week with insecticide when a post-emergent herbicide is applied.
15 July: "Photos taken Wed 2 July, and the crop was at the 6-7 leaf stage. The crop recieved another 8 mm rain on 1 July. The crop was sprayed with the herbicide glyphosate (as Roundup) at 900 g/ha around 23 June along with the insecticide Le mat for mite control. The weeds have died off or yellowed and the crop is looking very healthy. Another 15 mm+ has fallen today and last night since these pictures were taken. Next pictures on 15 July."
20 July: The crop is now at the 6-8 leaf stage and buds have begun to form at the base of plants. It has reached full canopy closure, which is ideal for this growth stage. Since the application of herbicide, the crop appears is virtually weed-free, with all weeds either dead or dying. The dense crop should smother most late germinations.
After the previous photos were taken on 3 July, another 36 mm rain fell at the site. And since this round of photos were taken a further 13 mm has fallen. The grower would like to topdress the crop urea soon, but at this stage it is too wet.
2. Plant density:
Different sowing rates were used for different varieties. Generally 4.5kg/ha was used for TT varieties and 2.7kg/ha was used for RR and Clearfield varieties. Plants of high densities would have the appearance of being spindly due to competition, while the crop of lower plant densities would have thicker stems, appear stronger and more robust.
Roundup Ready - plant densities range from 47 - 131 plants/m2 with an average of 76. Low densities of RR Hyola varieties were affected by "poor seed"
Triazine tolerant - plant densities range from 156 - 173 plants/m2 with an average of 164.5 which is well above the GRDC recommendations.
"Target populations for TT varieties in low rainfall environments should be maintained at 60 to 70 plants per metre square."
Clearfield - plant densities range from 61 - 102 with an average of 86.3.
**Plant density differences would give the appearance that TT varieties were not as robust as RR and Clearfield varieties.
3. Early Vigour
Hybrids are bred for early vigour. RR and Clearfield varieties were almost all hybrids but because TT hybrids are not planned for release until 2009 they were not used in TT comparisons.
Seed size of TT varieties was medium while seed size of RR and Clearfield varieties were almost all extra large. This would affect early vigour as there is improved vigour in large seeds. Early vigour rating (1 poor - 5 very good):
Roundup Ready - Rated 2.5, 3.0 and 4.5 for hybrids and 4.0 for open pollinator (large seed). Low performance of RR Hyola varieties was explained by " Poor seed quality affected emergence and early vigour".
Triazine tolerant - Rated 2.5 and 2.5.
Clearfield - Rated 4.0, 4.0 and 5.0.
** As GM and Clearfield hybrids were compared to non-hybrid TT varieties, it is expected that early vigour would be far better. It is of surprise that some RR hybrid varieties rated the same lack of early vigour as non-hybrid TT varieties.
Statement by Andrew Broad (GM grower): "Easy to do stewardship program as Monsanto give you the answer if you get it wrong"
Julie Newman
Phone 08 98711562
