PESTS have started making their mark across the State, with the Department of Primary Industries and Regional Development (DPIRD) reporting that mites and lucerne fleas have started hatching, while slugs and snails have started to lay eggs.
Mites and lucerne fleas have been found in Mingenew, Dongara, Narrogin, Mt Barker and Wittenoom Hills.
Hilary Wittwer, Wittwer Operations, Cuballing, has reported finding redlegged earth mites (RLEM) on Roundup-Ready canola volunteers near Narrogin.
RLEM have also been observed in the Mt Barker region.
Agronomy Focus senior agronomist Quenten Knight, Esperance, recently found Bryobia mites on HyTTec Trophy canola near Wittenoom Hills.
DPIRD staff conducting pitfall trap surveys in the Mingenew and Dongara area have found tiny lucerne fleas indicating a recent hatch from eggs in the area.
No RLEM were found in traps which supports Cesar Australia's redlegged earth mite egg hatch calculator which currently predicts "rainfall and temperature conditions not yet met" for Mingenew and Dongara.
However, RLEM egg hatching in the area is probably not far off given they have hatched at Narrogin.
RLEM egg hatching often happens on the south coast first then trending northwards given the lower daytime temperatures, however soil moisture is also an important factor.
DPIRD reminds growers that RLEM and lucerne flea have different environmental requirements for hatching of over-summering eggs and the difference in time can be important when considering insecticide application timing and length of efficacy such as post sowing pre-emergent sprays.
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Correct identification of mites is critical for effective control, as different species can vary in their susceptibility to certain insecticide groups, either naturally or through insecticide resistance.
Chemicals applied for control of the wrong pest may result in expensive loss of plant seedling density or having to resow some paddocks.
Before spraying mites, DPIRD urges growers to consider if the crop is out-growing the feeding damage.
In many years, and under good growing conditions, mites emerge from eggs during or after crop germination and the plants outgrow mite feeding damage.
Slugs and snails have been identified laying eggs in South Stirlings, Wellstead and Mt Barker.
Nutrien Ag Solutions agronomist Kieran Zilm, Albany, has found small pointed snails causing damage to germinating canola at South Stirlings.
The paddock has already been baited and will be baited again to protect the crop.
Black keeled slugs have been observed laying eggs in the Mt Barker region.
Baiting straight after seeding can control slugs however, budget for more than one bait to control snails.
DPIRD entomologist Svetlana Micic said a grain cleaner took about 40 tonnes per hour and a snail roller took 40-50t/h of canola per hour to remove snails from harvested grain.
However, some double snail rollers can take up to 60t/h.
She said baits shouldn't be crushed too finely to get more baiting sites per square metre.
Jasmine Peart
Jasmine is a earnest listener and a passionate advocate for justice. She feels privileged to be trusted by farmers across Western Australia to tell their truth.
Jasmine is a earnest listener and a passionate advocate for justice. She feels privileged to be trusted by farmers across Western Australia to tell their truth.
