Challenges with caterpillar and aphid pests in brassicas have long been an issue with growers trying to keep their crop clean and healthy in the lead-up to grazing.
Left unchecked, pests can quickly turn a healthy paddock into one with leaves riddled with holes, seriously affecting the quality and quantity of the feed.
In the past, growers have relied on more broad-spectrum insecticides to try to control the different pests. This option wipes out key beneficial insects and has also led to some pests becoming resistant to the chemical.
Agricultural company FMC recently released Exirel insecticide to the Australian forage brassica market as a control option for cabbage white butterfly, centre grub, diamondback moth, native budworm, soybean looper and grey cabbage aphid.
FMC’s Leandro Posteraro said the registration of Exirel was a great positive for Australian forage brassica growers wanting to keep their crops clean and maximise yields.
“Exirel controls a wide range of caterpillar pests and also has activity on grey cabbage aphid, so is a cross-spectrum option for both chewing and sucking insects,” he said.
Exirel works on the muscle function of the pest so the insect stops feeding very quickly for almost immediate protection of the plant.
Mr Posteraro said growers should regularly scout their paddocks to monitor for caterpillar eggs and larvae or aphid numbers.
“Apply when insects or damage first appear and before a build-up of pest numbers. There is an option to apply two applications per season and back-to back sprays work particularly well.
“Exirel works particularly well because it has translaminar and locally systemic action meaning it will move through the leaf and target pests in hard-to-reach places.
“We would expect between 10 and 14 days residual activity from Exirel, although growers often see longer periods between pest issues.”
He said a key benefit of Exirel was it had little to no effect on key beneficial insects.
“This means the friendly bugs that pollinate or feed on pests are not wiped out. They can stay in the crop to help control the next generation of pests.”
Mr Posteraro said beneficial insects such as ladybirds, lacewings and parasitoid wasps feed on aphids and caterpillars.
“Damsel bugs also target caterpillars and hoverflies eat aphids.
“Growers can use a highly effective insecticide for caterpillars and aphids and leave the beneficial insects in the crop to continue their good work.”
He said Exirel allowed a better balance between pests and their natural enemies for more efficient and effective pest management.
It also has a low-use rate, with a 10-litre container treating more than 66 hectares of area.
“It has low impact to mammals, birds and fish, algae and aquatic plants. PPE requirements are limited to gloves and cotton overalls,” Mr Posteraro said
“With its good margin of safety, it’s an excellent choice for applicators. Workers entering the field can do so after the spray has dried.”
Exirel for forage brassicas is available at local distributors.