Trials show nematode threat to canola yields
Author: Natalie Lee | Date: 09 Feb 2017
Latest information about the resistance (impact on nematode densities) and tolerance (impact on yield) of canola varieties to root lesion nematodes (RLN) will soon be unveiled at Western Australia’s premier grains research forum.
Department of Agriculture and Food (DAFWA) senior nematologist, Sarah Collins, will discuss the impact of these microscopic organisms on oilseed crops during the second day of the Grains Research and Development Corporation’s (GRDC) Grains Research Update, Perth. This will be held at Crown Perth on February 27 and 28.
Dr Collins said RLNs were an ‘invisible threat’ to canola in the western region, with current research showing that the two most common nematode species in the western region – Pratylenchus neglectus and P. quasitereoides – can cause major yield losses impacting on grower profitability.
She said these RLNs were widespread in WA cropping areas and developing an understanding of the effects of rotational crops, such as canola and lupins, on RLN densities would improve the industry’s ability to determine their potential effects on subsequent cereal crops.
“Likewise, an understanding of potential yield impacts caused by RLN on canola, lupin/pulse, wheat and barley varieties will help us estimate the total potential economic effects of RLNs in the western region and aid in making appropriate choices for infested paddocks,” Dr Collins said.
“Root lesion nematode densities can be managed using resistant crops that reduce nematode numbers and/or tolerant crops that have reduced yield loss in the presence of RLN.”
GRDC-funded trials carried out by DAFWA during the past two years at Wongan Hills and Gibson have shown there can be significant reductions in crop yields as a result of medium to high P. neglectus or P. quasitereoides populations at sowing.
In these concurrent trials, yield loss in canola was highest and consistent – compared to cereal crops – with an average 16 per cent yield loss caused by both RLN species tested.
Losses in cereal varieties were more variable, ranging from no yield loss to 15 per cent yield loss in wheat and no yield loss to 7 per cent loss in barley.
“In our trial series, lupins consistently reduced levels of both P. neglectus and P. quasitereoides without affecting yield,” Dr Collins said.
“This confirms that lupins are a reliable break crop for these RLN species.
“Our trials at Wongan Hills found lupins reduced nematode numbers by 37 per cent when RLN densities were medium to high at the beginning of the growing season.
“Growers can expect that a move to include lupins in crop sequences will provide effective RLN management in infested paddocks and potentially improve yield potential for other crops in the next season.”
Dr Collins said the trials also showed that crop variety selection could reduce potential yield impacts caused by the RLN species P. neglectus and P. quasitereoides.
But she said where starting levels of these nematodes were medium to high, substantial yield loss may occur for all varieties of triazine tolerant (TT) canola tested.
Further data from Dr Collins’ research will be presented at the GRDC Grains Research Update, Perth, which will feature wide-ranging information and latest grains research results from more than 50 presenters and five international speakers.
This event will be complemented by three one-day GRDC Grains Research Update events to be held in Mingenew, Kendenup and Merredin to enable growers to access a subset of the available information of particular relevance to their region.
These regional events are scheduled for the Mingenew Recreation Centre on February 24, the Kendenup Lodge on March 7 and the Merredin Recreation Centre on March 9.
Sarah Collins, senior nematologist
Department of Agriculture and Food
0404 488 113
Natalie Lee, Cox Inall Communications
0427 189 827
GRDC Project Code GIA00004
GRDC Project code: GIA00004
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