1 Edition 73 Friday, December 19, 2014 This edition includes 1. Fungicide withholding periods for straw and post‐harvest grazing 2. Call for cereal rust and Ramularia samples 3. TPP and potato growing degree days 4. Upcoming FAR events – including 2015 Conference 1. Interpretation of fungicide withholding periods for straw and post‐harvest grazing in ryegrass seed crops. It is important that growers are aware of their obligations when trading straw which has been treated with fungicides for the control of disease e.g. stem rust (Puccinia graminis subsp. graminicola). This is of particular importance in crops where the residue (or seed/grain) may be used as animal feed. When products are registered through ACVM (Agricultural Compounds & Veterinary Medicines) legislation, they are required to include withholding periods for both re‐entry of livestock to the paddock where treatment has occurred and for the use of forage (straw) to prevent accumulation of fungicide residues in livestock. The advantage of applying fungicides for the control of stem rust has been demonstrated in many FAR trials with turf type perennial ryegrasses, where seed yield increases of up to 50% are common. However, stem rust cycles rapidly when canopy temperatures are hot and few fungicides offer protection outside 14 days in mid‐summer. Therefore it is important to consider withholding periods for both straw and grazing of crop regrowth. As harvest approaches, growers will need to carefully consider their options if fungicide treatment is required, the options are: 1. Do not apply fungicide that contravenes the specified withholding period. This may involve a yield loss if disease is present, 2. If fungicide is applied that contravenes the withholding period, either burn or incorporate all crop straw and seed, ensuring livestock cannot ingest crop residues. 3. Undertake a fungicide residue test, at the grower’s cost, to ensure residues are at or below the maximum residue limit (MRL) for the product. Be aware ‐ For all fungicide products, harvest is considered as cutting, not threshing.
Transcript
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Edition 73 Friday, December 19, 2014
This edition includes
1. Fungicide withholding periods for straw and post‐harvest grazing 2. Call for cereal rust and Ramularia samples 3. TPP and potato growing degree days 4. Upcoming FAR events – including 2015 Conference
1. Interpretation of fungicide withholding periods for straw and post‐harvest
grazing in ryegrass seed crops.
It is important that growers are aware of their obligations when trading straw which has been treated
with fungicides for the control of disease e.g. stem rust (Puccinia graminis subsp. graminicola). This is of
particular importance in crops where the residue (or seed/grain) may be used as animal feed.
When products are registered through ACVM (Agricultural Compounds & Veterinary Medicines)
legislation, they are required to include withholding periods for both re‐entry of livestock to the
paddock where treatment has occurred and for the use of forage (straw) to prevent accumulation of
fungicide residues in livestock.
The advantage of applying fungicides for the control of stem rust has been demonstrated in many FAR
trials with turf type perennial ryegrasses, where seed yield increases of up to 50% are common.
However, stem rust cycles rapidly when canopy temperatures are hot and few fungicides offer
protection outside 14 days in mid‐summer. Therefore it is important to consider withholding periods for
both straw and grazing of crop regrowth.
As harvest approaches, growers will need to carefully consider their options if fungicide treatment is
required, the options are:
1. Do not apply fungicide that contravenes the specified withholding period. This may involve a
yield loss if disease is present,
2. If fungicide is applied that contravenes the withholding period, either burn or incorporate all
crop straw and seed, ensuring livestock cannot ingest crop residues.
3. Undertake a fungicide residue test, at the grower’s cost, to ensure residues are at or below the
maximum residue limit (MRL) for the product.
Be aware ‐ For all fungicide products, harvest is considered as cutting, not threshing.
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Interpretation of the labels for the main fungicides used in ryegrass seed crops. For further
information see Table 1.
Opus® Label withholding period:
1. Do not harvest ryegrass seed crops within 21 days of last application. This means the ryegrass seed crop should not be cut or direct headed within 21 days of the last Opus application.
2. Allow 35 days from last application until re‐entry of stock for grazing. This withholding period means that livestock can re‐enter the seed crop 35 days after the final application as long as the combined or cut straw has been removed from the paddock. i.e. last application approx. mid head emergence and prior to flowering.
Proline® Label withholding period:
1. Ryegrass seed crops 14 days. This means that livestock can re‐enter the seed crop 14 days after
the final application as long as the combined or cut straw has been removed from the paddock.
2. Ryegrass forage 35 days. In seed crops this means that the straw from seed crops cannot be
feed to livestock unless the final application was 35 days prior to cutting i.e. last application
approx. mid head emergence and prior to flowering.
Comet® Label withholding period:
1. Do not harvest ryegrass seed crops within 21 days of last application. This means that the ryegrass seed crop should not be cut or direct headed within 21 days of the last Comet application. The Comet® label states a final application at the end of flowering, Zadoks GS 69.
2. Allow 35 days from last application until re‐entry of stock for grazing. This withholding period means that livestock can re‐enter the seed crop 35 days after the final application as long as the combined or cut straw has been removed from the paddock. i.e. last application approx. mid head emergence and prior to flowering.
Amistar® Label withholding period:
1. Green feed / silage from ryegrass seed crops: 28 days. This with‐holding period means that
sheep can re‐enter the seed crop 28 days after the final application.
2. Grain crops: 35 days. In seed crops this means that the straw from seed crops cannot be feed to
livestock unless the final application was 35 days prior to cutting i.e. last application approx.
mid head emergence and prior to flowering.
Seguris Flexi® Label withholding period:
1. Ryegrass seed crops: 14 days. Seguris Flexi can be applied up to 14 days before cutting with no
issues associated with grazing re‐growth or feeding crop residue.
Table 1. Trade name, active ingredient and withholding period for products registered and commonly used in ryegrass seed crops, ALWAYS ensure you read and follow the label instructions before using the product.
Active ingredient Trade name
Withholding period Label link
Triazole
Cyproconazole Alto® 30 days http://www3.syngenta.com/country/nz/SiteCollectionDocuments/Labels,%20SDS,%20HazNotes/Labels/ALTO%20LABEL%20TEXT%20SEPT12.pdf
Pyraclostrobin Comet® 35 days until introduction of stock http://www.basf.co.nz/Libraries/Product_Documents/Comet_Label.sflb.ashx
Trifloxystrobin Twist® 35 days http://www.cropscience.bayer.co.nz/en/~/media/Bayer%20CropScience/Country‐New‐Zealand/Product%20Downloads/Fungicides/Twist/Twist%20Label.ashx?force=1
SDHI
Isopyrazam Seguris flexi®
Ryegrass seed crops ‐ 14 days http://www3.syngenta.com/country/nz/SiteCollectionDocuments/Labels,%20SDS,%20HazNotes/Labels/SEGURIS%20FLEXI%20SQUASH%20LABEL%20TEXT%20%20APRIL13.pdf
Mixtures Epoxiconazole + Carbendazim
Atomic 21 days do not graze or feed treated crops for 35 days
ALWAYS ensure you read and follow the label instructions before using the product.
Please check individual labels for generic formulations of common fungicide brands to make sure that the same label conditions apply.
If in doubt about any of the issues raised in this technical update then please contact your agrichemical supplier or the manufacturer directly.
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2. Survey of cereal rust and Ramularia
FAR and Plant & Food Research are carrying out a survey of cereal rusts and Ramularia with the aim of
understanding exactly which strains of these disease are present in New Zealand crops.
To do this we need to collect:
as many rust and Ramularia samples as possible
from as many regions as possible
from as many cereal cultivars as possible.
If you grow cereal crops, run research trials, are an agrichemical company representative, commercial
agronomist, independent consultant or anyone connected with cropping we need your help. Please
send us rust samples from your wheat, triticale or barley crops and Ramularia from your barley crops.
Rusts include wheat stripe rust, wheat leaf rust, and barley leaf rust. Ramularia infects barley only. Collecting rust and Ramularia infected leaf samples from the field
1. Collect 5 to 7 leaves with rust pustules or Ramularia on them from a single field or single wheat/barley cultivar.
2. Collect leaves a minimum of 10 days after the crop has been sprayed with fungicide. 3. Place leaf samples from each field in a paper envelope. For the rust samples make sure the
leaves are folded inwards. 4. Different cultivars from the same field should be kept in separate envelopes. 5. Do not use plastic bags because they will cause leaves to rot quickly. 6. Fill out the attached form for each sample. 7. Please mark envelopes for the attention of Soonie Chng or Rachael Warren and send to:
By post: By courier: Plant & Food Research Plant & Food Research Private Bag 4704 Canterbury Agricultural Science Centre Christchurch, 8140 Gerald Street, Lincoln
Note: If it is not possible to mail the rust samples immediately, samples can be kept in envelopes in the fridge for up to 2 days. Ramularia samples should be stored at room temperature, not in the fridge.
What do rust infections look like?
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Stripe rust infection on the leaves and in the head (Photos: Hugh Wallwork & Richard Chynoweth).
Leaf rust infection on wheat leaf
What does Ramularia infection look like?
Photos: Ian Harvey
Why is it important to know which rust pathotypes are present in New Zealand?
Cereal cultivars are protected from rust diseases by particular rust resistance genes. If we know what rust
pathotypes or strains are present, we can determine how new cultivars may react. Rust populations can
change over time depending on what cultivars are grown. In addition, new pathotypes can be generated
or introduced which change cultivar reactions. Being aware of the nature of these changes allows
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pathologists and breeders to examine how other cultivars being bred or selected for New Zealand might
behave. When pathotypes change or there are new introductions, cultivars that were previously resistant
can be rendered susceptible. An example of the effect of a new pathotype was seen recently with milling
wheat cultivar Conquest, which was very resistant to leaf rust prior to 2010, but very susceptible after
that season.
What will happen to the rust samples?
Plant & Food Research will prepare and store the samples at ‐80o C until next autumn when they will be
analysed. Australian experts will travel to New Zealand once a year to determine the rust pathotypes.
Why is it important to collect Ramularia samples?
In Europe Ramularia is now resistant to strobilurin fungicides (e.g. Acanto). There is some evidence from barley fungicide trials in New Zealand that strobilurins are not as effective at controlling Ramularia as they used to be. It is important to have an understanding of the sensitivity of the Ramularia population to different fungicides to design effective fungicide programmes. FAR and Plant and Food Research want to test Ramularia resistance to both strobilurin and SDHI fungicides.
What will happen to the Ramularia samples?
The same method will be used as for the Septoria tritici blotch testing last year. In the laboratory
Ramularia samples will be grown on plates of agar. A number of fungicides at up to 12 rates will be
applied to the fungus to determine how sensitive the Ramularia is to the fungicide.
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Cereal rust and Ramularia sample collection form
Name:
Company:
Address:
Phone:
Location where sample collected:……………………………………………………………………….
Circle best described: Crop / Trial / volunteer / others (specify……………………..)
3. TPP and degree days for the New Zealand potato growing regions
Psyllids in Canterbury Psyllid has been identified from FAR traps in Canterbury in recent days. Numbers are not high, but this proves that the psyllids are definitely present. The following graphs show accumulated degree days (DD) from 1 July 2014. The graph for each region also contains accumulated degree days for a hot and cold year in that region, to allow you to make comparisons with the current season. The number of TPP generations for the current season so far is indicated on the graph with a yellow arrow. These graphs will be updated weekly on the Potatoes New Zealand website until early May 2015, and will continue to appear in Crop @action as well.
Psyllids are active throughout the year and therefore 1 July is an arbitrary starting point.
It is important to be aware of other plants near your crop that can sustain TPP and act as a source of infestation. These include nightshade weeds, African boxthorn, poroporo but also volunteer potatoes.
Since the psyllid research is a work in progress, we strongly advise you to use the degree day graphs in conjunction with crop monitoring using sticky traps and plant sampling. Crop monitoring provides valuable information on TPP arrival, population build up and the life stages present in your crop (see the links below for a sticky trap monitoring brochure).
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Contact information For further information please contact Natasha Taylor, Research Associate, Plant and Food Research, ph: (06) 975 8880, email: [email protected]
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4. Upcoming events
The following events are planned for January and February 2015. Exact details will be confirmed closer
to the time.
Potato trials tour: Southbridge & Dorie
1.30 – 6.00 Wednesday 14 January
Potato field day: Cheltenham
1.00pm – 3.00pm, Wednesday 21 January
Maize trials field walk: Waikato Arable Research Site
4.00 – 6.00pm, Thursday 22 January
Southland field day:
Tuesday 27 January – exact times and locations to be confirmed.
FAR Conference 2015
22 – 23 July, Ashburton
In 2015 the Foundation for Arable Research will be 20 years old. To celebrate this milestone we have
chosen Future visions for the arable industry as the theme for our conference, which will be held at the
Ashburton Trust Event Centre on Wednesday 22 and Thursday 23 July 2015.
The conference will feature international keynote speakers, as well as presentations from industry, CRIs
and FAR staff. There will be four sessions: Cereals, Farm Systems, Seeds and Potatoes, as well as a field
trip afternoon. The Seed and Potato sessions will run concurrently.
We are still working on the programme for this event, but pencil it into your dairies now, and we will
send out more information as it is confirmed.
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Wishing you a Merry Christmas, Happy New Year and a Trouble free Harvest
