Global Plant Protection News

From PestNet

Thursday, 20 February 2020 13:38:40

Graham Walker responded to the submission ‘FAW – Devastating pest hits Australian mainland’.

Response for submission

FreshPlaza
https://www.freshplaza.com/article/9191224/devastating-pest-hits-australian-mainland/

Fall army worm detected
A potentially devastating crop pest, the fall army worm, has been detected on the Australian mainland. Just weeks after its first sighting in Australia in islands in the Torres Strait, Queensland Department of Agriculture and Fisheries (DAF) officials confirmed there had been a positive identification of fall army worm at Bamaga on Cape York in far north Queensland.

Biosecurity Queensland general manager of plant biosecurity Mike Ashton said a suspect moth collected at Bamaga was tested and confirmed to be fall army worm. He said it highlighted the pest’s ability to move rapidly in clement conditions. “This detection follows recent confirmed detections on two Torres Strait Islands, Erub and Saibai and underlines how quickly this pest can spread.”

The incursion of the pest, which can be damaging to a range of crops from cereals to fruit trees, means government officials will have to formulate a response swiftly to minimise potential impact. Surveillance programs will now be in full swing in northern Queensland, including rich agricultural regions such as the Atherton Tablelands, along with the coastal fringe from Cairns to Mossman.

“Biosecurity Queensland has proposed a response plan that is being considered by the national Consultative Committee on Emergency Plant Pests,” Mr Ashton said. He said farmers needed to consider their own responses. “Growers should have on-farm biosecurity measures in place to protect their crops from pests and diseases.”

In terms of identification Mr Ashton said fall armyworm larvae were light coloured with a larger darker head. “As they develop, they become browner with white lengthwise stripes and also develop dark spots with spines,” he said. In the moth phase he said adult moths are 32 to 40mm in length wing tip to wing tip, with a brown or grey forewing and a white hind wing.

Source: farmweekly.com.au

Publication date: Wed 19 Feb 2020

Response

FYI, I have seen the damage caused by FAW to corn crops in central Vietnam since it’s arrival there about a year ago. We can’t stop the spread and establishment of the moth because it is such a strong flying moth, no doubt arriving in NZ as well soon. I have some observations on damage and control. It obviously prefers grasses, and will be a major pest of corn and maize, and probably sugar-cane and sorghum. But I am not seeing it as a major pest on other vegetable or fruit crops yet. In central Vietnam, although a new pest, I have only seen it causing major damage on corn crops. Nearby crops, mainly vegetable crops don’t appear to be affected. It obviously prefers corn, and the damage is very obvious. The egg-masses are laid on the leaves and the minor damage caused by small gregarious caterpillars is easy to see, However, larger caterpillars move down into the whorls where they are protected and nearly impossible to control. However, they are cannibalistic so you normally only find small numbers in a whorl. However, large caterpillars can destroy a lot of plant material. Control can be by regularly scouting the crop, and when the egg-masses and masses of gregarious small caterpillars are seen, remove and destroy them. If you leave the crop not monitored, suddenly the foliage and crop may disappear (eaten by large caterpillars).  I don’t know what it might do in rice and sugar-cane crops, and elephant grass yet, because I am working mainly in vegetable crops, with other nearby vegetable crops not affected (as discussed above). No doubt other grasses will be a reservoir where the local populations will build up. FYI, I have produced a simple factsheet with photos from a corn crop in Vietnam that I could make available if useful?

Graham Walker