"We've had some hatchings around Binnaway, but conditions are very dry there at the moment so we're expecting those locusts to do it pretty tough," Mr Robinson said.

The survival of the eggs is dependent on "soil moisture and temperature". Dry conditions can kill the eggs, as well as the hatched larvae and young locusts.

Mr Robinson said eggs that were laid in the first half of March are ready to hatch, "if they haven't already".

"Particularly if we get a good rain event I think we'd see them come out fairly quickly, so farmers really need to be on the ball."

He said rainfall earlier in the week was "patchy" and only encouraged locusts to hatch in certain areas.

"With these patchy rain events we get staggered hatchings, so it drags it out a bit."

It would be preferable for widespread rain to fall, to "bring them all out" at once, he said.

To kill the locusts, Local Land Services provide landholders with the contact insecticide fenitrothion, which is not residual and has a short withholding period, so it doesn't affect livestock.

Landholders must identify and monitor viable egg beds, so they can spray the newly hatched larvae when they are banded together on the ground.

It's particularly important to know exactly where egg beds are for continued monitoring, as eggs can survive over the winter and emerge in spring, Mr Robinson said.

"If they find an egg bed, mark it with a steel post, it will help them keep an eye on that egg bed."