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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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