On-farm grain storage systems are under the spotlight in Mingenew this harvest to assess their impact on pest incidence and grain seed viability.
PHOTO: Ben White
Mid-west grain growers are among the first in Western Australia to compare the efficacy for seed quality of a range of on-farm grain storage systems. They are involved in a new research partnership supported by the Plant Biosecurity Cooperative Research Centre (PBCRC) and the GRDC to assess how grain storage affects the vigour, viability and germination of wheat seed used for subsequent plantings.
This is WA’s first comprehensive study of the relationships between grain quality going into storage, its susceptibility to and incidence of stored grain insect pests, use of aeration and phosphine fumigations, and seed viability for sowing.
Members of the Mingenew–Irwin Group (MIG) are leading the project, using 20 gas-tight, sealed silos – each with 70-tonne capacity – on four local farms. Trial data will feed into a national project coordinated by the PBCRC at six grain-growing locations across Australia to improve the management of storage pests.
MIG executive officer Sheila Charlesworth says little is known in WA about the potential effects of grain storage and insect pests on seed germination and vigour.
“If only 70 or 80 per cent of stored seed grain is viable, then growers have to compensate by increasing seeding rates – leading to extra costs,” she says.
“We also want to understand more about minimising the risks surrounding pest resistance to phosphine, especially for our major pests – lesser grain borers and weevils.”
Effects of grain storage
Little is known about the effects of grain storage on seed grain viability in Western Australia. A GRDC-funded trial at Mingenew is testing the hypothesis (Figure 1) that:
- stored grain insect pests and storage conditions impact on seed grain viability and vigour;
- pest populations are driven by grain quality and ambient conditions; and
- grain quality is affected by moisture content at harvest, temperature, ambient conditions and type of storage system used.
FIGURE 1 Project working hypothesis.
Associate Professor Christian Nansen, from UWA, inspects stored grain in front of seed silos in Mingenew, where trials are underway to assess grain storage systems.
Research engineer Ben White says there are several options that reduce reliance on phosphine fumigations.
He says the most important are harvest equipment and storage hygiene, which will be a common denominator across the MIG trial.
Treatments being used in the replicated trials at Mingenew this harvest are:
- hygiene only – no treatment/control in common farm silos;
- hygiene with controlled aeration;
- hygiene with diatomaceous earth structural treatment; and
- grain turning in the silo.
Grain moisture content has been measured as each of the trial silos was filled following the start of the current harvest.
Temperature and humidity data loggers have been installed inside and outside the bins and are now tracking conditions and changes in grain moisture content. Falling numbers and insect pest occurrence are also being monitored.
University of WA Associate Professor of applied entomology Christian Nansen and research associate Jerome Gumley are carrying out seed viability tests every month from each silo in the four treatments.
This involves putting seed in germination vials to see how it grows.
Associate Professor Nansen says if germination variability is high as the summer progresses, they will also test for early plant vigour.
“We don’t yet know how grain moisture levels at harvest, types of storage systems and pests are affecting seed viability, germination and vigour,” he says.
“But if this pilot trial indicates that some storage options are better than others at maintaining seed viability, it may lead to more widespread trials across the WA wheatbelt.”
Field days are planned for the MIG trials during the summer to showcase the four storage treatment options.
Mr White will also be conducting workshops to highlight the importance of hygiene practices when storing wheat seed, especially to minimise exposure to pest damage.
Further information about these events is available from the GRDC grain storage extension website (www.storedgrain.com.au) and the MIG website (www.mingenew-irwin.asn.au).
Sheila Charlesworth, MIG, 08 9928 1645, firstname.lastname@example.org;
Ben White, Kondinin Group, 0407 941 923, email@example.com;
Christian Nansen, UWA, 08 6488 8672, firstname.lastname@example.org;
David Eagling, PBCRC, 0458 456 467, email@example.com;
Stored Grain, www.storedgrain.com.au
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