BEWARE seasonal carryover of root lesion nematodes. University of Adelaide researchers Vivien Vanstone and Michelle Russ have shown that some annual and broad-leaf weeds can host nematodes and therefore may allow population build-up or carryover from season to season.
Dr Vanstone says the finding could mean that the full benefits of growing resistant crops to control nematodes are not achieved. "Differences between the two Pratylenchus species in weed susceptibility further emphasise the need for growers to identify which nematode species is present when making management decisions," she said.
The following table produced by Dr Vanstone and Ms Russ gives a good overview of the Pratylenchus host status of weed species.
non-host = resistant (nematodes do not multiply)
|Weed Species||P. neglectus||P. thornei|
|Indian hedge mustard||NON||NON|
|Wild oat||VERY GOOD||POOR|
poor host = slight build-up of nematode numbers
good host = susceptible (nematodes multiply)
Compared to Machete wheat (susceptible) and Abacus triticale (resistant)
Dr Vanstone said Pratylenchus research was continuing at the University of Adelaide with emphasis on assessing the P. neglectus resistance of new lines from Dr Tony Rathjen's wheat breeding program. She said some of this material looked very promising.
Break crops reminder
Crops including field peas, lentils, medic and durum wheat are rated resistant to the root lesion nematode Pratylenehus thornei, while peas, lentils and faba beans are resistant to P. neglectus.
Some wheat and barley varieties have moderate resistance to these pests while canol a varieties are rated as moderately susceptible or susceptible to P. neglectus, but moderately resistant to P. thornei.
Program 2.6.2 Contact: Dr Vivien Vanstone 08 8303 7456