IT’S a relatively new pest to Australia and only arrived on our shores in 2020 but Fall Army Worm (FAW) and its ability to decimate crops such as corn and sorghum continues to keep growers on high alert.
Rob Bell grows lucerne, corn and soybeans on his farm at Coochin.
It’s his corn crops that have him on edge because maize is a preferred food source for FAW.
Mr Bell will harvest between 150 to 200 tonnes of corn from 16ha of farmland dedicated to the crop. He works the land alone and this means the job of visually inspecting the crop for signs of the voracious pest is time consuming.
“FAW caused a huge problem last year in the lower Fassifern for corn growers but didn’t have an effect on me, most likely because I’m fairly isolated from other farms,” said Mr Bell.
“We still must spray, which we did once last year but some farmers are spraying three or four times for FAW.
“I’ve got corn that’s just out of the ground so it’s a case of monitoring and making sure you get onto it if the moths appear.”
He said the first thing to look for is skeletal stripping of leaves because the caterpillar eats the leaf part around the veins.
“If you see that happening you know they are there, then you check the whorls and leaf nodes to make sure they are not in there as well,” he said.
“You’ll have a couple of critical points where you’re able to reduce the damage, but you will never be able to eliminate them altogether.
“It’ll become about reducing the impact and this is done at whorl stage because that’s generally where the caterpillars lay their eggs.
“When the eggs hatch as the crop is forming is probably the most critical time to monitor and control.”
He said spraying of crops was done by helicopter or through pivot irrigation systems on larger farms.
“You have to get on top of it really quickly, there are also new pheromone traps that alert you to their presence,” he said                                                                                  “I’m being vigilant because I’ve put a bit more [corn] in this year because it’s going to be wet again.
“That’s how it is with a lot of pests and weeds, we have to monitor and then balance out the economics of controlling it and getting on top of it before it spreads.”
The FAW’s name describes the way larvae (caterpillars) march in large numbers away from sites where their food has run out. They also find crops when the adult form (moths) fly in in preparation to lay their eggs on a food source.
“We’ve had such a cold winter that hopefully the larvae damage will be reduced because they stay semi-dormant in the soil and emerge when its spring and planting time,” he said.
“When corn is just emerging, like mine is now, they’d only be able to get to the two or three inches that are above ground level.”
Mr Bell planted his corn crop three weeks ago. It takes approximately 120 days from time of emergence for the crop to mature.
His harvest is sold to manufacturers as ingredients for foods such as breakfast cereal and corn chips.