growers@sgcotton.com.au Roger Tomkins - Greenmount Press

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The reasons for this are complex but again in partly due to the introduction of Bt cotton. The reduction in sprays, and particularly endosulfan, caused aphids to require more tactical targeted control with Pirimor or an OP so exacerbating resistance. From the early 1990s, sustainable cotton aphid control quickly became an industry priority with the recovery of Pirimor considered most important. An IPM based resistance management strategy was developed that did eventually recover Pirimor (Figure 3). The recovery of Figure 3: Per cent strains of cotton aphid containing Pirimor resistant individuals between 2000–01 and 2011–12 *13 out of 37 strains complete in 2011–12. Figure 4: Per cent strains of cotton aphid containing neonicotinoid (e.g. Cruiser or Shield) resistant individuals between 2004–05 and 2011–12 *11 out of 37 strains complete in 2011–12. Pirimor is again complex and multi factorial but in part due to the introduction of new group of insecticides known as the neonicotinoids. This group of insecticides containing products such as Cruiser, Shield and Confidor was initially very effective but again cotton aphid showed its resilience and developed resistance. resistance was not restricted to one product but all the neonicotinoids used against it. resistance was initially only detected in two strains at low frequencies but within a season resistance had dramatically increased in both level and abundance with resultant control failures (Figure 4). resistance then increased up until season 2010–11 when nearly all strains tested were neonicotinoid resistant but last season resistance was less frequently found (although all testing is not yet complete). The reasons for this are again complex because the amount of neonicotinoid seed dressing used has not diminished and a higher rate product called Cruiser extreme was made available. I consider it likely that the foliar use of neonicotinoids against pests other than aphids has changed and aphids are not receiving the same concurrent selection they once did (i.e. being in the wrong place at the wrong time when another pest is sprayed). The development of neonicotinoid resistance in cotton aphid is a blow to the industry because it is both cost effective and efficacious. A possible solution to the evolution of neonicotinoid resistance forms part of a PhD study being undertaken by Kate Marshall with funding by the CrDC. One of the initial tasks undertaken by Kate is to ascertain the practical implications of neonicotinoid resistance with respect to seed dressings and to investigate alternatives. Kate achieved this via two separate greenhouse based trials that firstly investigated neonicotinoid seed dressings challenged with neonicotinoid resistance aphids (Figure 5). Secondly a separate trial is planned with no insecticide seed dressing but rather a Thimet soil granule that was challenged with Pirimor/dimethoate resistant aphids. It is clear from Kate’s study that Cruiser will not control neonicotinoid resistant aphids. The higher rate Cruiser extreme product worked better than Cruiser but still survivors were evident at the second 14 day post sowing challenge. Additionally, Kate reports she did see a survivor against Cruiser extreme at day seven in an earlier preliminary trial. If Kate’s second trial is successful and Thimet can used as an alternative to a neonicotinoid seed dressing, foliar use of neonicotinoids for aphid control may again become a reliable option. So aphid control in Australian cotton has now come full circle in about a decade. IPM friendly Pirimor that was once lost to resistance is now again a mainstay control. The neonicotinoids continue to be at risk but their resistance profile is improving. Bean spider mite all but vanished from Australian cotton but now seems to be making a resurgence. Figure 5: Average number of live neonicotinoid resistant aphids per plant on untreated (control) or neonicotinoid treated (350 or 600 g/L) cotton 7–49 days post sowing (destroyed seven days post each challenge) 22 — The Australian Cottongrower August–September 2012
Water Matters… Series supported by Valmont Case study: Pipes through the bank ■ Nikki Pilcher and Mary Philp, Queensland Department of Agriculture Fisheries and Forestry sAunders FArming Pty ltd Owners: Craig and Sharon Saunders Location: St George Total area: 3000 hectares Cotton area: 647 hectares 2010–11 yield: 11.25 bales/ha 2010–11 water: 7.2 ML/ha Field length: 500 to 1700 metres CRAIG and Sharon Saunders own and run three irrigated cotton, dryland wheat and grazing properties in the St George area. The original property “Ford Park” has been in the Saunders family for more than 40 years, with Craig and Sharon taking over management in the 1990s. Four years ago Craig joined forces with Justin Schultz FIGuRE 1: Cross-section view of PTB irrigation system of WaterBiz to investigate alternatives to traditional siphon irrigation. As a result Craig and Justin designed and constructed a siphon-less watering utilising pipes through the bank (PTB) with variable rates of flow. Each pipe waters 11 furrows or 12 metres and is designed to suit the 12-metre machinery in use. Saunders Farming also operates a centre pivot machine irrigating 89 hectares with a system capacity of 10.1 mm per day. This machine is located on Craig’s marginal country, irrigating red hard setting soils. Motivator for change It was initially thought that the main motivator for change four years ago was water savings, and a 25 per cent water saving has been achieved. But looking back, the team has realised that the real motivator was actually labour. The team have not only achieved this water saving, but have also had a labour saving of 50 per cent and yield increase of 20 per cent. Justin has found that the main water savings are not a result of the pipes but by optimising the flow rate and the run times. In the 2010–11 season the traditionally lowest yielding farm actually Cotton being irrigated with pipe through the bank system. Precision Irrigation Made Easy CENTRE PIVOT and LATERAL MOVE IRRIGATION August–September 2012 The Australian Cottongrower — 23
Page 1 and 2: August-September 2012 www.cottongro
Page 3 and 4: In this issue... 2012 Cotton Grower
Page 5 and 6: The trouble with buying old technol
Page 7 and 8: We’re with you from the beginning
Page 9 and 10: BE READY FOR ULTIMATE PRODUCTIVITY
Page 11 and 12: Roger Tomkins: 0409 100 036 Louise
Page 13 and 14: Field proven irrigation power John
Page 15 and 16: 16th Cotton Conference roundup AFTE
Page 17 and 18: Delegates may have found out more t
Page 19 and 20: You’re in control of your future.
Page 21: 2013 FARM STUDY TOURS For More Info
Page 25 and 26: Valley ® Strongest in the industry
Page 27 and 28: Nutrition feature… Impact of nitr
Page 29 and 30: (ADVERTORIAL) Local Trials Show Bio
Page 31 and 32: SOIL organic carbon (SOC) is an imp
Page 33 and 34: and minimise the loss of stubble-C.
Page 35 and 36: WORLD COMMODITY WATCH India Specula
Page 37 and 38: documented, the Chinese state reser
Page 39 and 40: 3100% Australian Cotton 3100% Austr
Page 41 and 42: for the position between the gin st
Page 43 and 44: The trial crop has yielded around s
Page 45 and 46: FIGuRE: 3 Relationship between EM34
Page 47 and 48: Temik, is in short supply and is sc
Page 49 and 50: The joys (or otherwise) of tractor
Page 51 and 52: in Australia), when it finally erup
Page 53 and 54: Germinating ideas By CSD Extension
Page 55 and 56: Evaluation of insecticides for cont
Page 57 and 58: NEW Holland’s most powerful tract
Page 59 and 60: Students visit cotton districts CAL
Page 61 and 62: District Reports… Central Queensl
Page 63 and 64: Darling Downs The 2012 cotton seaso

growers@sgcotton.com.au Roger Tomkins - Greenmount Press

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