NATIVE budworm moth traps have been set up early again this year for most grainbelt regions and initial results indicate budworm moth movements have begun early for the Geraldton and Kwinana East port zones.
The moths migrate long distances annually from the north and eastern pastoral areas down and west into the grainbelt.
While growers should be vigilant for this pest, they do not need to be alarmed.
Department of Primary Industries and Regional Development (DPIRD) staff have been setting up the native budworm pheromone moth trapping network, along with Mingenew Irwin Group, West Midlands Group, Liebe Group and South East Agronomy Services.
Over the past two weeks many of the traps have caught varying numbers of budworm moths:
- Beacon: 228
- Irwin: 102
- Eradu: 78
- Mingenew: 64
- Nabawa east: 47
- Dandanning: 27
- Miling: 17
"This indicates budworm moths have begun to migrate into the grain growing areas, mainly in the northern and north-eastern grainbelt and are likely to have started laying eggs onto crops," said DPIRD development officer Dustin Severtson.
"From July onwards farmers are encouraged to check lupin, canola and pulse crops for the presence of budworm caterpillars."
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A farmer near Mingenew recently sweep netted an early flowering canola crop and found one budworm caterpillar in five lots of 10 sweeps.
Native budworm moths lay white spherical eggs (0.5 millimetres) singly, mostly near the top of the plant.
The eggs darken as they mature and tiny caterpillars hatch after about seven days.
Dr Severtson said the small caterpillars will cause minor leaf damage that is not obvious, such as tiny holes chewed into leaves.
"So they can initially go unnoticed if crops aren't being checked with a sweep-net," he said.
"The young caterpillars feed on leaf or pod material for about two weeks before they become large enough (5mm long) to be noticed in the crop.
"However, as the caterpillars get larger in the coming weeks they can cause severe damage particularly if they coincide with pulse crops budding, flowering or early pod formation."
It takes a further four weeks until they are fully grown (40mm) which is about seven weeks from the time of egg laying.
These development times are based on average spring temperatures and while temperatures are still relatively warm in the northern agricultural region, these development times will be extended in areas experiencing cooler winter temperatures.