SRA8 – Smut Update – Rob Milla
Hi All,
I am writing to inform you of an update to the Sugarcane Smut situation in the Burdekin region, with specific reference to SRA8. BPS staff detected elevated levels of smut in SRA8 at BPS approved seed cane plots in Mid August 2017 – since then, SRA pathology staff have inspected these sites and provided feedback. It should be noted that SRA8 has a smut rating of Intermediate-Susceptible, so seeing the expression of smut in this variety when conditions are favourable for smut is not unexpected. Up until August 2017, very little smut had been observed in SRA8.
The Regional Variety Committee (RVC) met on Tuesday 29th August to decide on how best to manage SRA8 with the presence of smut. Rob Magarey (SRA Pathologist) was also present, along with other senior SRA staff. Management of SRA8 was discussed at two levels – commercially planted blocks, and BPS approved seed cane plots.
Commercially planted Cane
Advice from SRA pathology staff, and supported by all members of the RVC was that growers who have planted SRA8 have no need to plough out any cane. The relatively small areas that have been planted, even if they were showing levels of smut consistent with an Intermediate-Susceptible variety, would not significantly increase pressure on the district as a whole. If growers have concerns or questions regarding SRA8 that they have planted commercially, please contact BPS staff for assistance. In terms of yield loss, it is difficult to quantify the extent as we have only observed SRA8 up to 2nd ratoon, however it is unlikely there would be significant yield losses in plant and early ratoon crops.
BPS Approved Seed Cane Plots
Varying levels of smut were found in SRA8 in BPS approved seed plots across the district. Given that smut is a wind borne fungal spore, it is not possible to protect the plots from this method of transmission, even though all other precautions to minimise risk of smut infection such as hot water treatment, clean down of equipment and planting with Sinker have been taken. Advice from pathology was that once smut infestation exceeds 1% on approved seed cane plots, then the levels of smut become unacceptable, particularly given the Burdekin situation where we have a number of major varieties (particularly Q183 and Q208) in the intermediate range for smut susceptibility. A decision was made by the RVC to plough out first ratoon cane in distribution plots where the threshold of 1% of plants infected with smut has been determined. There are two distribution plots where very low levels of smut were detected in SRA8, and these will be monitored over the next few weeks and will not be ploughed out unless they exceed the threshold.
Please be aware that the decision by the RVC to plough out approved seed plot SRA8 was made in order protect other varieties within the plots that are in the intermediate range for susceptibility to smut and minimise risk to the greater industry. Those growers who have commercially planted SRA8 can continue to grow it for the crop cycle.
Other Background Information
It is worth noting that SRA plant breeders and researchers have noticed very elevated levels of smut in experimental variety trials within the Burdekin as well as other regions. The expression of smut is a combination of the variety susceptibility, the pathogen (ie: number of spores) and the environment. It appears that environmental conditions have favoured smut this year – particularly given that very little smut had been observed in SRA8 over the past 5 years. The response of SRA8 to smut is consistent with an intermediate-susceptible rated variety. In some years, if environmental conditions and/or spore loading are unfavourable for smut, then the intermediate-susceptible varieties will grow well with little effect, however if conditions favour smut, the effect will be far more noticeable. It is also worth noting that smut has not been observed in SRA8 plant cane to date, only 1st ratoon onwards.
The Regional Variety Committee comprises voting members from Wilmar, Kalagro, PCGO, ICGO and CBL. Other non voting members include representatives from BPS, SRA, independent growers, agronomists and industry personnel. Further information regarding the RVC, smut, SRA8 and other varieties will be discussed at shed meetings with BPS and Farmacist in October/November 2017.
SRA and BPS are working to establish some replicated smut monitoring trials in the region to obtain more detailed local information on how smut impacts varieties across the whole spectrum from resistant to intermediate. Trials will be established in both the drier and wetter parts of the district to determine how the local environment affects smut incidence. These data will be used to assist with deciding the level of smut resistance needed to minimise yield losses. It is hope to plant the first trial in 2017.
If you have any further questions, please feel free to contact your grower representative organisation for RVC matters, or BPS staff for technical questions around smut management on your farm.
Kind Regards
Rob Milla
Manager
Burdekin Productivity Services
Email: [email protected]
Ph: 07 4783 1101
Mobile: 0490 036 329
PO Box 237 Ayr QLD 4807
210 Old Clare Road, Ayr