Victoria's farmers are preparing for a "second generation" of the locust plague that has swarmed across the state since spring. Hundreds of rural landowners across northern and western Victoria have reported locust egg beds of up to 15 metres long.

The Department of Primary Industries (DPI) has had about 430 reports of locust egg beds, which, once hatched, will become the "second generation" of the locust plague. DPI state locust controller John Balfour said most of the reports of egg beds were across the north, central and Wimmera areas of the state, with some reported in other areas.

"The current concentration of egg beds is across the Horsham, Ararat, Stawell areas, through to Castlemaine, Bendigo and then on through Shepparton and further east towards Rutherglen and Wodonga," Mr Balfour told AAP.

The egg beds can be up to 15 metres long, consisting of eggs laid by the plague of locusts that have swarmed across Victoria since spring. A farmer in Katunga, in the state's central north, has also reported the first hatching of a second generation egg bed.

Mr Balfour said landowners needed to be talking to local chemical suppliers to prepare for spraying egg beds as hatching begins this month and hoppers emerge to feed on the ground. He said this hopper stage, before the locusts began to fly, was the only stage at which the locusts were vulnerable to treatment.

"Landowners have a legal obligation to treat locust hoppers on their property and that is because by doing so they prevent the effects of locusts, that is damage to their own crops and then prevent the hoppers developing to fly off and damage others' crops elsewhere."

Mr Balfour said the vigilance landowners had shown so far in reporting locusts had helped contain and reduce the plague threat to Victoria.

"I think there's no doubt the vast majority of people from the locust-affected areas heard about the locust problem through the DPI campaign ... and their timely action has had a very positive impact on the swarm levels."

Motorists travelling through locust-affected areas, where swarms of "first generation" locusts are still flying across highways, should also follow some basic tips to deal with vision problems and blocking radiators. These are to make sure their windscreen washers are filled with water, to consider screening their radiators, to slow down and if necessary, pull over if driving through a swarm.

Mr Balfour said radiator screens could prevent large numbers of locusts flying into and blocking the radiator, causing the car to overheat.

Source: Australian Associated Press