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ChiCkpea disease management strategy

VIEWS: 43 PAGES: 6

									        ChiCkpea disease
      management strategy
                                               Northern Region 2008



  ■    Disease management in chickpeas is critical and relies heavily on an integrated management package
       involving paddock selection, variety choice, strategic fungicide use and crop hygiene.
  ■    Paddock selection on the basis of Phytophthora root rot risk is the first priority followed by cropping
       history. The appropriate Ascochyta blight control strategy is then adopted by determining the level of risk
       in combination with climatic conditions and the level of resistance afforded by the variety chosen.
  ■    Disease control strategies may not be economic in high risk situations if Ascochyta blight susceptible
       varieties are grown.



 sUmmary
 •	 Paddock history. Aim for a break of at least 3 to                     •	 Sowing date. Aim for the optimum sowing window
    4 years between chickpea crops. Assess the risk                          for your region. Plantings made earlier than the
    of Phytophthora root rot (PRR) prior to planting.                        recommended planting time tend to be more
    Paddocks with a history of PRR in chickpeas, medics                      vegetative, and are more predisposed to Ascochyta
    or lucerne are extremely risky and should be avoided.                    blight, Botrytis Grey Mould and frost damage.
                                                                          •	 Sowing rate. Aim for a plant population of 20 to 40
 •	 Paddock isolation from chickpea stubble is a high                        plants/m2, adjust seeding rate according to seed size
    priority. Aim for a separation of at least 500 m.                        and germination test.
 •	 Variety selection is critical as it influences disease                •	 Foliar fungicides are essential for Ascochyta blight
                                                                             susceptible varieties. Ascochyta blight resistant
    control strategies. Growing an Ascochyta blight
                                                                             varieties do not require as many fungicide sprays
    resistant variety reduces but does not eliminate the
                                                                             as susceptible varieties. Details of fungicide
    need for foliar fungicides.
                                                                             requirements can be found in the current VMP for
 •	 Seed source. Use seed from a paddock where                               each variety (see Pulse Australia web site
    disease was not detected, especially on pods. Do                         www.pulseaus.com.au).
    not use seed known to be infected with Ascochyta                      •	 Foliar fungicide success for Ascochyta blight depends
    blight, particularly with Ascochyta blight susceptible                   on timeliness of spraying, correct fungicide choice
    varieties. Seed for planting in Central Queensland                       and correct application. Early detection, correct
    (CQ) must be sourced from CQ crops.                                      disease identification and early, effective control are
                                                                             essential.
 •	 Seed treatment with fungicide dressings is essential.                 •	 Complacency. Growers are urged not to become
    They control seed borne Ascochyta blight and seed                        complacent about controlling Ascochyta blight,
    borne Botrytis Grey Mould. They also control several                     as it has the potential to hit hard very quickly
    soil borne fungal diseases.                                              (see pages 4 & 5).


   sponsored by:




Gordon Cumming – Northern Development Officer, Pulse Australia, Toowoomba - Ph: 0408 923 474
Kevin Moore – Senior Plant Pathologist, NSW DPI, Tamworth - Ph: 02 6763 1133
Mal Ryley – Principal Plant Pathologist, QDPI&F, Toowoomba - Ph: 07 4688 1316                                           Version 1: 2008
phytophthora root rot                                                         Variety selection
Paddocks with a history of naturalized burr medic, chickpea or                The choice of variety will vary according to area, disease risk,
lucerne, and especially those with a history of Phytophthora                  harvestability issues, yield and marketing considerations. As
root rot (PRR), are extremely risky. Phytophthora is particularly             well as the level of Ascochyta blight resistance, growers will
severe in areas prone to waterlogging and flooding.                           put varying emphasis on Phytophthora root rot resistance
Disease inoculum can gradually build up over several seasons                  as well as plant and pod height, depending on their
on sparse populations of burr medic and then explode under                    requirements.
wet conditions.                                                               Consult your agronomist and assess the disease risk for
Assess the risk of Phytophthora root rot prior to planting,                   Ascochyta blight, Phytophthora root rot and virus for each
and select a variety with some resistance if there is any                     paddock before selecting a variety. In many cases the selection
likelihood of this disease.                                                   of two or more varieties might help to spread risk.

table 1: Chickpea variety ratings for common chickpea diseases in Northern Australia.
                                                                Phytophthora
         Description              Ascochyta Blight                                       Botrytis Grey Mould                       Viruses
                                                                  Root Rot
                                      Genesis    090
                                      Genesis    508
          Resistant
                                      Genesis    509
                                      Genesis    425
   Moderately Resistant                   Flipper                    Yorker                                                         Gully
   Moderately Resistant               Almaz, Nafice,
                                                               Flipper, Jimbour,
            to                           Yorker                                                                                    Flipper
                                                                 Kyabra, Moti#
  Moderately Susceptible
                                                                 Genesis 425                     Genesis 509,
  Moderately Susceptible
                                                                   Howzat                        Howzat, Moti#
                                                                                                                            Amethyst, Almaz,
                                                                                            Almaz, Amethyst,
                                                               Almaz, Amethyst,                                           Bumper, Genesis 090,
                                                                                          Bumper, Genesis 090,
                                       Amethyst,                 Genesis 090,                                                 Genesis 508,
                                                                                              Genesis 508,
         Susceptible                Howzat, Jimbour,             Genesis 508,                                                 Genesis 509,
                                                                                          Genesis 425, Flipper,
                                     Kaniva, Kyabra              Genesis 509,                                            Genesis 425, Howzat,
                                                                                         Jimbour, Kaniva, Kyabra,
                                                                 Gully, Nafice                                           Jimbour, Kaniva, Kyabra,
                                                                                              Nafice, Yorker
                                                                                                                              Nafice, Yorker
                                     Bumper, Gully,            Bumper, Kaniva,
      Very Susceptible                                                                               Gully
                                    Macarena, Moti#              Macarena
Note: These are provisional Pulse Breeding Australia national ratings.
      They are for average disease pressure at the start of the season and average conditions for the disease during the season.
      Ratings will vary with inoculum load and seasonal conditions.
      # Moti is not to be grown south of Theodore, Central Queensland.

paddock selection and On-Farm hygiene.                                        Treat all seed with a suitable fungicide seed dressing. Ensure
Ascochyta blight infected stubble blown about during and                      all planting seed is of high quality (purity, germination
after harvest is the major cause of short to medium distance                  and vigour).
dispersal (metres to kilometres). Further, the Ascochyta blight               DO NOT mix inoculant with fungicide seed dressing
fungus can increase rapidly on volunteers and dead chickpea                   Using seed with low vigour often results in;
stubble especially if wet conditions occur during the spring-                 •	 Patchy,	uneven	plant	stands
summer-autumn periods. Paddocks with chickpea stubble should                  •	 Slower	early	growth
be regarded as a high level source of inoculum even if Ascochyta              •	 Lower	yields
blight was not observed in last season’s chickpea crop.
                                                                              •	 Uneven	and	delayed	maturity.
Keep a 3-4 year break between chickpea crops. Avoid planting
adjacent to, or in close proximity to, last year’s chickpea                   Table 2: Seed dressings registered for the control of
paddocks, no closer than 500 m but further if down wind                       Ascochyta blight and seedling Botrytis Grey Mould.
or down slope. All volunteer chickpeas need to be removed                                                            Active             Rate (per
during fallows and summer crops. Remember that if the fallow                    Trade Name          Company
                                                                                                                   Ingredient         100 kg seed)
period is especially dry, chickpea stubble will take longer to
                                                                               Thiragranz®         Crop Care         Thiram
decompose and that stubble residues from the previous two                                                                                   150 g
                                                                                                                    800 g/kg
years may need to be considered.
                                                                               Thiraflo® ST        Chemtura
plant high Quality seed with a low risk of                                                                           Thiram
                                                                               Thiraflo FF
                                                                                         ®
                                                                                                   Chemtura                             200	mL
ascochyta blight infection                                                                                          600	g/L
                                                                               Thiram  ®
                                                                                                   Crop Care
Aim for a plant population of 20 – 40 plants/m2. Source
seed from a crop were Ascochyta was not detected                               P-Pickel T    ®
                                                                                                   Crop Care      Thiram + TBZ
                                                                                                                                        200	mL
(low risk seed).                                                               Fairgro   ®
                                                                                                   Farmoz        360	+	200	g/L
                                                                              TBZ = thiabendazole.
Botrytis grey mould                                                     Viruses
Botrytis Grey Mould (BGM) is present in all production areas            Viruses have caused serious losses particularly in the higher
but is more prevalent in the humid, warmer regions.                     rainfall	areas	such	as	the	Liverpool	Plains.	
BGM can attack the plant at any growth stage. As seedling               The risk of Virus problems can be reduced by agronomic
blight it can reduce plant establishment significantly if               management practices including;
infected seed is sown without a fungicide seed dressing.                •	 Retention	of	cereal	stubble	to	deter	aphids.
Significant crop losses can occur from flowering onwards                •	 Sowing	 at	 recommended	 times	 to	 avoid	 autumn	
during wet spring conditions. Particularly if crops have dense              aphid flights.
canopies, resulting in rapid disease development.                       •	 Sowing	 at	 recommended	 rates	 to	 achieve	 early	 crop	
Control BGM by using seed from disease free crops, applying                 canopy closure (to deter aphids).
a seed dressing, crop canopy management such as the use                 •	 Control	 broadleaf	 weeds	 that	 harbour	 viruses	 and	
of wider rows to allow for greater air movement and using                   their vectors.
protective foliar fungicides.                                           •	 Distancing	crops	from	lucerne	or	other	green	areas	that	
Spray programs for the control of Ascochyta blight also control             can act as reservoir’s for aphids.
stem and foliar BGM.
With the more Ascochyta blight resistant varieties (Flipper,
Yorker) now being grown, a specific spray for BGM may be
required. The fungicide carbendazim should be used due to its
systemic activity providing better protection to newly emerged
flowers compared to mancozeb and chlorothalonil.
Check the APVMA website for the latest Warnings and Safety Directions
on carbendazim use. www.apvma.gov.au
                                                                                         Scattered Virus infected plants

table 3: Chickpea Foliar Fungicides
                                                                                                           Rates
       Trade Name                         Company             Active Ingredient
                                                                                      Ascochyta Blight           Botrytis Grey Mould
 Barrack 720   ®
                                   Crop Care
 Barrack Betterstick
               ®             ®
                                   Crop Care                                          Under Permit No.
 Unite 720
       ®
                                   Nufarm                                                  9814
                                                           Chlorothalonil	720	g/L
 Unite Ultrastick
       ®                ®
                                   Nufarm
 Bravo®                            Syngenta                                            1.0	–	2.0	L/ha	
 Bravo Weather Stik®               Syngenta
 Dithane Rainshield
               ®
                                   Dow AgroSciences
 Penncozeb 750DF   ®
                                   Nufarm
                                                            Mancozeb 750 g/kg          1.0 – 2.2 kg/ha              1.0 – 2.2 kg/ha
 Innova    ®
                                   Syngenta
 Mancozeb                          Various
 Penncozeb 420SC   ®
                                   Nufarm                    Mancozeb	420	g/L          1.8	–	3.95	L/ha
 Dithane SC    ®
                                   Dow AgroSciences          Mancozeb	430	g/L	         1.85	–	4.0	L/ha
 Bavistin      ®
                                   Crop Care
 Carbend       ®
                                   Nufarm
                                                           Carbendazim	500	g/L                                        500	mL/ha
 Spin Flo      ®
                                   Nufarm
 Howzat®                           Farmoz




                       Phytophthora Root Rot                                                  Botrytis Grey Mould
                           determining your ascochyta Blight risk
The northern GRDC region has three levels of ascochyta blight risk, determined by:
• proximity to infection source;
• seed infection and treatment; and
• variety grown.
Ascochyta blight management strategies vary accordingly and are strongly influenced by weather conditions. The key to
achieving cost effective management of Ascochyta blight is to assess the risk level for each paddock, and then manage
each accordingly.

Chickpeas grown in all areas other than Central Queensland       The majority of crops grown in the western areas often meet
are classified as either at Moderate or High Ascochyta           these criteria i.e. west of the Darling Downs in Qld and west
blight risk. Assessment should however be done on a              of the Newell highway in NSW.
paddock-by-paddock basis and not on a regional basis.            Do not use the disease status of your previous chickpea
                                                                 crop(s) as the main criterion in assessing Ascochyta blight
There definitely are some high-risk situations in the more
                                                                 risk. If favorable conditions for the build-up of disease on
western, drier areas given the right seasonal conditions for     stubble or volunteers occur over summer/autumn this
Ascochyta blight to develop.                                     approach will fail.
high ascochyta Blight risk situations                            Low ascochyta Blight risk situations
Disease epidemics can develop rapidly in situations where        The only region that currently can be genuinely considered
chickpeas are being grown within a 2 km radius of previous       LOW	RISK	is	Central	Queensland	(Central	Highlands	and	the	
chickpea stubble paddocks. For this to occur the following       Dawson/Callide). Ascochyta blight has not been detected in
combination is needed:                                           Central Queensland and the key management strategy for
• A source of Ascochyta blight inoculum, either as diseased      this region is to keep it that way by not bringing in planting
     crop residue or resulting from a build-up of inoculum on    seed (and Ascochyta blight) from outside the CQ area.
     volunteers or chickpea stubble (wet summer/autumn)          All planting seed should be sourced from CQ and treated with
     and                                                         a suitable fungicide. Always check the origin of your planting
• Wet conditions conducive to disease infection and              seed prior to delivery and ensure that machinery entering
     spread.                                                     the region has been thoroughly cleaned.
Most of the more intensively farmed areas such as the Darling    Ascochyta blight could impact if it is introduced, so be
Downs and east of the Newell highway in NSW are in this          prepared to act should it occur.
High Risk category by the very nature of the farming system.     For additional information refer to the brochure “Protocol
A number of crops in the western areas are potentially in        for managing an outbreak of chickpea Ascochyta blight in
this category if they are planted within 2 km of the last two    central Queensland”.
year’s chickpea stubble.

moderate ascochyta Blight risk situations
This applies to situations where both of the following two
criteria occur:
• Chickpeas are being planted at least 2 km away from
    inoculum sources such as the last 2 years chickpea
    stubble paddocks, volunteers and spring trap crops
    and                                                                                                              Ascochyta,
• Seed has been sourced from crops where Ascochyta                                                                  leaf leasions
    blight has not previously been detected and has been
    treated with a suitable fungicide seed dressing.
                                                                     Ascochyta, leaf ghosting 4-7 days after rain




            the key to effective ascochyta blight management is based upon:
            •	 Select	varieties	with	the	highest	possible	Ascochyta	blight	resistance,	which	are	suitable	for	your	
               region.
            •	 Use	of	clean	treated	seed	and	paddock	isolation	from	inoculum	sources.
            •	 Timely	and	efficient	use	of	protective	fungicides.
            •	 Spray	equipment	set-up	specifically	for	timely	fungicide	application.
            •	 Having	access	to	a	chickpea	agronomist	competent	in	monitoring	for	the	disease.
            •	 Avoiding	low	yield	situations	(low	soil	water	or	presence	of	subsoil	constraints)
ascochyta Blight Control strategies                                         Ascochyta blight susceptible varieties ,
Consider the variety grown, potential crop yields, rainfall zone            (eg: Howzat, Jimbour, Kyabra), regular, sustained foliar
and disease risk when deciding on fungicide use.                            fungicide applications will be necessary. Apply a fungicide
In high risk areas, there is very little margin for error in either         before the disease is detected, from emergence through
timing or application technique of fungicide sprays. The timing             flowering until 4 weeks before maturity.
of the first fungicide spray is critical in delaying the onset              Timing of the first two programmed protective sprays is
and spread of the disease in the crop.                                      critical, as control is often ineffective if fungicides are
                                                                            applied after the disease has taken hold. The first spray
Ascochyta blight resistant and moderately
                                                                            must be applied either prior to the first rain event after crop
resistant varieties (eg: Flipper), there is no cost                         emergence, or three weeks after emergence or at the three
benefit in applying a fungicide until after Ascochyta blight                leaf stage. The second programmed spray should be applied
is detected.                                                                3 weeks after the first, but if two weeks have elapsed since
Monitor the crop 10-14 days after rain events and if Ascochyta              the first spray and rain is forecast, apply the second spray
blight appears to be spreading, either:                                     irrespective of the number of weeks after emergence.
• apply 1 kg/ha of dry formulation product containing 750                   Mancozeb at 1 kg/ha is the preferred fungicide for these first
    g/kg mancozeb (Dithane Rainshield®, or equivalent); or                  two applications. It can be applied alone, or with a Group
•	 prior	 to	 next	 rain	 event,	 apply	 1.0	 L/ha	 of	 one	 of	 the	       A grass herbicide. Continue monitoring as a third or fourth
    six products currently listed on the APVMA Permit 9814                  fungicide spray may be required depending on if weather and
    containing	720	g/L	chlorothalonil.                                      disease levels indicate Ascochyta blight is spreading.
Continue monitoring and spray again if weather and disease                  If Ascochyta blight is spreading under the mancozeb regime,
levels indicate Ascochyta blight is spreading.                              or if significant wet weather is forecast, then switch to
                                                                            chlorothalonil.	Use	1.0	to	2.0	L/ha	of	one	of	the	six	products	
Ascochyta blight intermediate resistant (MR-MS)                             currently	listed	on	the	APVMA	permit	9814	containing	720g/L	
varieties (eg: Yorker), apply a fungicide prior to the first rain           chlorothalonil.
event after crop emergence, or three weeks after emergence
or at the three branch stage of development, whichever occurs                 any fungicide program needs to take into account:
first. Use 1 kg/ha of dry formulation product containing 750
                                                                              •	 Varietal	susceptibility	or	resistance
g/kg	mancozeb	(Dithane	Rainshield	or	equivalent);	or	1.0	L/
ha of one of the six products currently listed on the APVMA                   •	 Source	of	seed	and	treatment	of	seed
permit	9814	containing	720g/L	chlorothalonil.	                                •	 Proximity	to	chickpea	stubble
Monitor the crop 10-14 days after a rain event. If Ascochyta                  •	 Level	of	Ascochyta	blight	inoculum	present	from	crop	
blight is found, then prior to the next rain event apply either                  residue or volunteer plants
2 kg/ha of dr y formulation product containing 750 g/                         •	 Climatic	conditions	for	disease	infection
kg	 mancozeb;	 or	 1.0	 L/ha	 of	 product	 containing	 720g/L	                •	 Cost	effectiveness
chlorothalonil. Continue monitoring and spray again if weather                •	 Level	of	Ascochyta	blight	present		
and disease levels indicate Ascochyta blight is spreading.

                                                Chlorothalonil Use Under permit
                                 A new permit for the use of chlorothalonil in chickpeas has been
                          Issued by the APVMA (No 9814), valid until January 2009 for six products only;
                     	                 •Crop	Care	Barrack®	720	              •Crop	Care	Barrack® Betterstick®
                     		                •Nufarm	Unite® 720	                   •Nufarm	Unite® Ultrastick®
                     		                •Syngenta	Bravo®	                     •Syngenta	Bravo	Weather	Stik®
                                                Be sure to observe the stipulations of;
                                        “Do not apply more than 4 applications to any crop”
                                      “Do not graze or feed crops or crop residues to livestock”




                                     Ascochyta blight blight, stem lesions and pynidia on dying plant material
Foliar Fungicide application guide                                                   Windy Conditions: The recommended nozzles will not
Mancozeb and chlorothalonil are protectant fungicides that                           be as effective in situations where the fungicide application
work by forming a protective coating over the surface of the                         is in windy conditions with wind speeds exceeding 20 km/
plant to prevent infection. New growth is unprotected. Timing                        hr. Fine droplets generated by these nozzles are susceptible
of the spray and effective application are critical if fungicides                    to drift.
are to work as intended (see pages 4 & 5).
                                                                                     If it is critical that the fungicide application proceeds due to
Recommended Application Technique                                                    impending rain, the best option under windy conditions is to
It is unwise to use spray rigs set-up for herbicide application                      select a nozzle with a larger droplet size (110-02 or 110-03).
and	hope	that	it	will	be	OK	for	the	application	of	fungicides.	
                                                                                     Larger	droplets	will	be	less	effected	by	drift,	but	increase	
For fungicides and insecticides to be effective, good foliage
                                                                                     water	volumes	to	120	L/ha	to	improve	coverage.
coverage is essential. Increasing fungicide rates does not
compensate for an inadequate application method.                                     Aerial Application: Whilst the use of ground spray
Nozzle Selection and Operation: To be effective,                                     rigs generally provides better spray coverage, the timely
fungicides rely on smaller droplets than those normally                              application that can be achieved by an aircraft under wet
recommended for herbicides. Select a flat fan nozzle that will                       conditions or when dealing with large areas can be of
produce a fine sized droplet and deliver an equivalent of 80                         benefit.
L/ha	at	the	desired	ground	speed.	At	higher	ground	speeds	
you may need to use two smaller nozzles on a double swivel                           The aircraft should be set up with a fine droplet setting, with
or a Teejet Twinjet® to produce the flow rate required, but in                       a	minimum	of	30	L/ha,	but	preferably	40	L/ha.
the fine droplet spectrum.
Water Volume:	Aim	for	80	L/ha	water,	and	preferably	100	                             Using a Contractor
L/ha.	In	heavy	or	dry	crops	the	more	water	the	better.	Water	                        Growers and advisors should fully discuss the application
should not exceed pH 7 for optimum results. High pH water                            requirements prior to spraying, and insist on them. Do not
needs to be buffered.                                                                just assume that the job will be done as recommended.
Additives: Follow label instructions when using fungicides.                          Inadequate application techniques will result in poor levels
Avoid experimenting with surfactants.                                                of disease control. Increasing the number of applications
While a “sticker’ may improve rain fastness, this is often at                        required, incurring greater costs and increasing potential
the expense of leaf coverage.                                                        yield losses.



Variety selection – Future releases of chickpea varieties will have better disease resistance than current varieties.




                          Figure 1 Flipper, (MR) no sprays                                                  Figure 2 Jimbour, (S) no sprays
                                                                Ascochyta blight resistance.
                           (Plots in the immediate rear are the same variety and have been sprayed for Ascochyta blight control).


DISCLAIMER – The information herein has been obtained from sources considered reliable but its accuracy and completeness cannot be guaranteed. No liability
or responsibility is accepted for any errors or for any negligence, omissions in the contents, default or lack of care for any loss or damage whatsoever that may
arise from actions based on any material contained in this publication. Readers who act on this information do so at their own risk. Past performance is not
indicative of future results. We do not endorse or recommend the products of any manufacturer referred to. Other products may perform as well or better than
those specifically referred to. Independent advice should be sought for any use of products. Check validity of current permits and labels of products prior to use.

								
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