Oct 31

Lupin disease confirmed in Riverina

Posted by Cindy Cassidy at Monday, October 31, 2016

NSW Department of Primary Industries (DPI) has confirmed the detection of the damaging anthracnose disease in lupin crops for the first time in NSW, and has alerted growers to inspect crops for symptoms.
DPI Plant Biosecurity Director, Dr Satendra Kumar, said DPI has joined forces with Local Land Services and industry to kerb the disease and eradicate the fungus from NSW production areas.
“Four albus lupin crops on two adjoining Riverina farms are affected and working with Local Land Services, farmers and industry advisers we aim to quickly eradicate the fungus to protect albus lupin production in NSW and the eastern states,” Dr Kumar said.
Lupin anthracnose causes lesions on plants, causing bent, twisted stems and pods, which can lead to complete pod loss and malformed, scarred seed - suspect symptoms must be reported to NSW DPI by calling the Exotic Plant Pest Hotline, 1800 084 881.
NSW has no natural hosts for the fungus and the current infected lupin crops are relatively isolated from one another, making successful eradication a promising prospect.
Stringent quarantine measures are maintained across the state to prevent the entry and establishment of this disease in NSW.
Lupin anthracnose is spread by infected seed and the fungus can be spread by contaminated machinery, vehicles, people, clothing, animals and fodder.
Initially detected by NSW DPI Plant Pathologist, Dr Kurt Lindbeck, and confirmed by laboratory DNA analysis at the Elizabeth Macarthur Agricultural Institute, the anthracnose damage was particularly severe in the affected lupin crops.
Riverina Local Land Services Agronomist, Lisa Castleman, encouraged all growers to look for signs of the disease and report any suspect cases.
Ms Castleman said lupin anthracnose incursions threaten the sustainability of albus lupin across NSW and all areas where lupins are grown in Australia.
“Enlisting the support of lupin growers is essential to gain rapid control of this outbreak, as we need to protect NSW lupin crops from this new threat,” said Ms Castleman.
Lupins are a significant winter crop for NSW producers with over 50,000 hectares sown to lupins this season.
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Apr 27

Preparing for planting 2016

Posted by Cindy Cassidy at Wednesday, April 27, 2016

Rain forecast for this weekend means Riverina farmers are in the middle of preparing for, and sowing, the 2016 winter crop, an integral part of Australia’s agricultural output. Riverina farmers produce $2.1 billion worth of total agricultural output annually (ABARES) with grain production alone worth $795 million annually.
As a part of the preparation for this year’s crop, farmers have been using stubble burning as an important tool in the management of their farming systems. But why do farmers burn?
There are lots of reasons why farmers burn crop residue, but the overriding issue is that this stubble residue will adversely affect their cropping program, which can be compromised if the stubble -
• causes blockages to seeding equipment
• causes uneven crop emergence
• perpetuates crop diseases
• provides habitat for crop pests
• affects the efficacy of weed control
• affects the uptake of nutrients by the new crop
Farmers retain their stubble for as long as possible to provide grazing for sheep, to reduce erosion risk and to retain moisture.
Southern NSW produces some of the highest crop yields and best quality grain in Australia. Average wheat yields of 3-4 tonnes/ha are common, and could be double that in a good year. A direct result of that is that there is large amounts of stubble to deal with before the next crop can be sown. Typically stubble residue can be 1.5 x the grain yield. Research has shown that if the amount of stubble exceeds 3 tonne/ha then many seeders will have difficulties in sowing crops evenly and there will be blockages as the stubble tends to clump up. Getting crops sown to emerge within the correct time period for each variety is so important for the end result. Agronomists spend a lot of time planning crop rotations with farmers and selecting varieties suitable for each paddock to avoid frost and heat stress in critical times in spring, and this depends on the sowing operation going smoothly.
Many crop diseases and pests are harboured in the old stubble residue, so depending on the crop rotation the stubble may need to be removed to prevent the problems. Fungal leaf diseases such as Yellow Leaf Spot in cereals and Blackleg in canola are carried over in stubble residue. Stubble burning reduces these risks in the paddock so that crop seedlings are not exposed to the disease at emergence. Pests such as earwigs, millipedes and slugs rely on stubble cover to improve their habitat in cropping paddocks and can damage emerging seedlings, especially fragile canola seedlings. Removing the stubble by burning can help prevent these from causing a problem.
Weed competition is the greatest threat to crop productivity worldwide, so early control is essential for ensuring that crop yields are not compromised, and the emerging crop can become competitive itself. Stubble can interfere with efficient application of herbicides. Soil active pre-emergent herbicides will not be effective if stubble cover absorbs the spray, preventing even application. Post emergent weed control may also be compromised if standing stubble is shading seedling weeds so that spray droplets do not reach the target so burning stubble before herbicide application will give better results.
The technique of windrow burning as a way of destroying resistant weed seeds is also becoming an important part of the integrated weed management package. Instead of spreading harvested weeds seeds across the paddock, stubble residues are simply dropped via a shute at the back of the header so they can be burnt in late summer or early autumn in a hot burn that destroys all the weed seeds. This allows the majority of the stubble to be conserved, but herbicide resistant weed seeds are destroyed.
Stubble residues can also affect the uptake of nutrients to crops in some circumstances. Cereal stubble from high yielding crops can have a carbon : nitrogen ratio of 80 : 1. When this residue is incorporated into soil it will provide a feedstock for soil microbes. Carbon from crop residues is the primary driver of soil microbial activity and this in turn leads to the release of plant nutrients. The problem here is that the microbes (bacteria and fungi) need other nutrients, particularly nitrogen to digest this carbon. Nitrogen is stripped from soil reserves to do this, hence there will be a short term tie-up of nutrients that are not available to the emerging crop. Farmers have the choice of adding more nutrient for the crop, having the stubble residue in contact with soil for a longer fallow period, or removing the stubble by burning to avoid these nutrient problems. Local research showed that grazing stubbles over summer helped to avoid this nutrient tie-up and redistribute the nutrients across the paddock. Care needs to be taken to not over graze the stubble and increase the risk of soil erosion by wind and water.
Farmers do their best to avoid any impact of smoke on nearby communities by observing some basic principles when conducting stubble burning, including -
• checking with the Bureau of Meteorology and local Rural Fire Authorities when weather conditions will be suitable for burning
• avoiding calm weather conditions that are associated with temperature inversions where smoke will hang in the air for long periods and can drift into local towns.
• burning stubble in the heat of the day with a good cross breeze to give a quick, hot burn.
• awareness of when winds will take smoke into neighbouring towns.
Burning stubble can be done at various strategic times for many reasons, but there is a need to be aware of the “big picture” how it fits into the farming system and how it can be done to minimise the effects on the community.
FarmLink is continuing its work in the GRDC Stubble Initiative to ensure farmers have the support of their local communities thanks to improved stewardship of stubble burning and ongoing sustainable farm management practices.

Sep 13

Pest Facts South-Eastern

Posted by Cindy Cassidy at Friday, September 13, 2013

As insect activity continues to increase over the coming weeks it will be important to keep a close eye on crops, particularly aphid and caterpillar pests.

Click here to view the latest isse of Pest Facts south-eastern for the 2013 winter-growing season.

Jul 01

Crop Disease Alert: Blackspot of Field Peas

Posted by Cindy Cassidy at Monday, July 01, 2013

In the last fortnight there have been a number of plant samples submitted and enquires regarding blackspot of field pea. 

The disease has started to appear in commercial field pea crops, particularly those sown early for manuring. 

Blackspot (as known as ascochyta blight) of field pea is the most common foliar disease of field pea in Australia and has traditionally been the main disease constraint to production. Back in the 1990's this disease was the main concern for producers and could result in significant yield losses if left unmanaged.  The dry years of the early 2000's in combination with reduced field pea sowing has resulted in a greatly reduced incidence of the disease until this year. 

The dry autumn this year in combination with a late autumn break and early sown field peas has been ideal for development of the disease.  This has resulted in conditions where airborne ascospores are being released from old field pea stubble under cool, wet conditions which is favouring rapid infection and development.  This disease is why the recommended sowing window for field pea in southern NSW is late May to late June, to avoid ascospore showers and disease development.   

The disease starts as discrete circular brown lesions on lower leaves, these enlarge with time to kill off whole leaves.  Stem infection will also occur with brown lesions appearing on the lower stem and crown of the plant, this will completely girdle the lower stem with time.  Stem infection reduces nutrient and water flow within the plant and reduces yields. 

The fungi that cause blackspot is a complex of three pathogens that can survive on the old stubble, on seed and as spores in soil ( a bit like brown leaf spot of lupin).  So management of the disease relies on paddock rotation, separation from last year's stubble, fungicide treatment of field pea seed for sowing (with P pickle T) or foliar fungicides (products containing mancozeb or chlorothalonil).  Foliar fungicide trials we conducted at the Institute in 1990's found that it was uneconomic to spray for blackspot (based on the price of fungicides at the time and the price of field pea).  Having said that we would often achieve yield increases of up to 30% in some field pea varieties.  Management of blackspot with foliar fungicides is most effective when the products are applied before the appearance of symptoms. 

No current field pea varieties have resistance to the disease.  Being a complex of three fungi it is difficult to breed for resistance.  However, it is generally regarded that the more erect field pea types have better tolerance to the disease due to canopy architecture. 

If field peas are to be sown for manuring diseases will become an issue, whether it be bacterial blight or blackspot.  These crops are not bred to be sown in April and not be expected to develop disease.  To maximise biomass the sowing time need only be a fortnight or 10 days earlier than ideal to see significant increases in biomass production.  Early sown peas will develop disease early and suffer reduced biomass and yield as a result. 

Further enquires. Contact Kurt Lindbeck, NSW I&I, Plant Pathologist P: 02 6938 1608