Management of field peas to reduce Ascochyta blight and maximise yield

Sarita Jane Bennett, Robert C. Lee, Anjana Sharma

Centre for Crop and Disease Management, School of Molecular and Life Sciences, Curtin University, Bentley, WA 6102, http://ccdm.com.au, sarita.bennett@curtin.edu.au  

Abstract

The legume field pea can be a valuable component of crop rotations to reduce cereal disease carryover and increase soil nitrogen. However, it is frequently affected by Ascochyta blight which reduces yield. Fungicides are used to control the impact of the disease with mixed success, but effective management relies on a combination of strategies. To determine the efficacy of management strategies for disease suppression, field trials were run investigating;

  • The interaction between time-of-sowing and fungicide treatment at three locations in Western Australia in 2016, with four fungicide treatments applied either once or twice after sowing.
  • The impact of using wheat stubble from the preceding crop to trellis the field peas, reducing crop lodging, and potentially disease spread.

Results showed that time of sowing had a greater impact on yield than repeated application of fungicide. Stubble-trellising using the previous year’s cereal stubble significantly reduced disease in the crop and increased yield.

Sensitivity of lentil genotypes to photosynthesis-inhibiting (Group C) herbicides

Tim Nigussie1, Jason Brand1, Mitchell Fromm1, Laura James1, Larn McMurray2

1 Agriculture Victoria, Department of Jobs, Precincts and Regions, 110 Natimuk Road, Horsham, Vic, 3400,  tim.nigussie@ecodev.vic.gov.au, 
2 Global Grain Genetics, Clare, SA, 5453

Abstract:

Lentil (Lens Culinaris M.) is a poor competitor with weeds and its sensitivity to herbicides make broad-leaf weed control challenging. Herbicide resistance due to overreliance on group B herbicides in herbicide resistant crop varieties has also become a concern. Group C herbicides control many broad leaf and some grass weeds. However, this group of herbicides have a low safety margin between phytotoxicity to weeds and to the lentil crop. Field experiments evaluated the Group C herbicide sensitivity of three lentil genotypes PBA Hurricane XT, PBA Jumbo and PBA Jumbo 2 in comparison to a new genotype (SP1333) with improved metribuzin tolerance. Diuron, simazine, metribuzin and terbuthylazine were applied post-sowing pre-emergence at various rates. All genotypes did not show sensitivity to 765 gai/ha of diuron and up to 3600 gai/ha of simazine and produced grain yield equivalent to their respective nil treatment. However, application of higher rates of metribuzin and terbuthylazine caused significant injury and a subsequent yield loss of up to 100%. SP1333 had better tolerance to lower rates of metribuzin, terbuthylazine and higher rates of diuron than PBA Hurricane XT, PBA Jumbo and PBA Jumbo 2, providing opportunity for breeding programs to develop varieties with improved tolerance to group C herbicides.

Lesion and sclerotia development in four pulse species when inoculated with different isolates of Sclerotinia sclerotiorum

Grace Elizabeth Lamont and Sarita Jane Bennett

Centre for Crop and Disease Management, Curtin University, Kent Street, Bentley WA 6102, grace.lamont@student.curtin.edu.au

Abstract:

The fungal pathogen Sclerotinia sclerotiorum has the potential to affect pulse crops as well as canola. Pulse crops are important break crops in cereal cropping systems, but rotations may need to be managed when canola is included in the rotation, as sclerotia, the hard melanised survival structures of S. sclerotiorum, can last up to seven years in soil. This research sought to determine the susceptibility to, and severity of, Sclerotinia stem rot in narrow-leafed lupin (Lupinus angustifolius), faba bean (Vicia faba), chickpea (Cicer arietinum) and lentil (Lens culinaris).

Three different isolates of S. sclerotiorum were inoculated onto plants and lesion length, plant height, pod count, survival and sclerotia count recorded. Lupins were the most susceptible, followed by lentil and then chickpea, with the greatest number of sclerotia recorded. There was a significant difference between species and between isolates. Faba beans were the most tolerant and no sclerotia formed within faba bean stems. Isolate CU10.12 was least virulent, causing the smallest yield penalty (pod count), the shortest lesions, no sclerotia, and no plant deaths. Isolate CU8.20 was the most virulent in all these measures. The isolate of S. sclerotiorum as well as the pulse in the rotation is therefore important when determining potential disease severity and future inoculum contribution when including pulses in the rotation.

Pasture legumes offer promise to control barnyard grass in delayed permanent water systems in rice

Jhoana Opena1, James Pratley1, Jeffrey McCormick1, Hanwen Wu12, and Deirdre Lemerle1

1 Graham Centre for Agricultural Innovation (Charles Sturt University and NSW Department of Primary Industries), School of Agricultural and Wine Sciences, Locked Bag 588, Wagga Wagga, NSW, 2678, jopena@csu.edu.au,
2 NSW Department of Primary Industries, Wagga Wagga, NSW, 2650

Abstract:

Australian rice growers endeavour to reduce water use in their rice crops due to high competition for scarce water resources. One method increasing in popularity is to drill sow rice and delay the application of permanent water. This water saving method however, provides an opportunity for the global weed barnyard grass to proliferate. Farmer anecdotes have suggested that the resultant barnyard population is determined to some extent by the lead-in crop or pasture. This paper considers the impact of particular pasture legumes on the barnyard grass seedbank and seedling establishment. Data show that there is some validity in the farmer experience with barnyard grass being inhibited by legume species as the lead-in ‘crop’.

Increasing wheat sowing rates can reduce winter weed numbers in a cotton-wheat rotation

Nilantha R. Hulugalle1,2, Benjamin J. Lenehan3,4, Guna Nachimuthu1 and Daniel KY Tan3

1Australian Cotton Research Institute, New South Wales Department of Primary Industries, Narrabri, NSW, Australia,
2 Present address: Fenner School of Environment and Society, Australian National University, Canberra, ACT, Australia,
3 The University of Sydney, Sydney Institute of Agriculture, School of Life and Environmental Sciences, Faculty of Science, Sydney, NSW, Australia
4 Present address: Delta Agribusiness, Harden, NSW, Australia, Email: daniel.tan@sydney.edu.au

Abstract:

Wheat is commonly sown in rotation with cotton in Australian cotton farming systems. Uncontrolled weed growth can inhibit wheat growth and thereby, have a detrimental effect on the following cotton crop. Weeds that are frequently found in wheat crops of north-western New South Wales (NSW) include deadnettle (Lamium amplexicaule L.), sow thistle (Sonchus oleraceus L.), and annual Phalaris (Phalaris paradoxa L.). The objective of our study was to quantify the effects of wheat sowing rates on weed populations and growth, and their impact on wheat growth and yield. An experiment that consisted of wheat sowing rates of 0 (fallow), 30, 60, 120 and 180 kg ha-1 was conducted during 2014 and 2015. Weed biomass, type (broad-leaved or grassy), and species diversity were assessed at wheat anthesis. Wheat phenological events (emergence, anthesis, maturity dates) were recorded and wheat biomass measured at 10 weeks after sowing (2015) and anthesis (2014, 2015), as well as grain yield. Weed populations at wheat anthesis consisted of broad-leaved weeds during 2014 and a mix of broad-leaved and grassy (annual Phalaris) weeds during 2015. Weed biomass decreased sharply when wheat was sown, even at the lowest sowing rate of 30 kg ha-1 and continued to decrease such that at the higher sowing rates it was negligible. Adequate yields can be attained by sowing wheat at rates in the range 30-60 kg ha-1. The costs associated with sowing at higher rates cannot be justified, although significant long-term reductions in the weed seedbank are likely only by sowing at these rates.

Host

The Australian Society of Agronomy is the professional body for agronomists in Australia. It has approximately 500 active members drawn from government, universities, research organisations and the private sector.

Photo Credits

David Marland Photography david_marland@hotmail.com Graham Centre for Agricultural Innovation, Charles Sturt University

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