Australian Pulse Bulletin

Lentil fungicide guide: 2021 season

Foliar fungicides will help manage the lentil diseases Ascochyta blight (AB) and Botrytis grey mould (BGM), but when to commence a fungicide program and how often to spray, depends on the varietal resistance, weather conditions and the potential yield of the crop. 

Pulse Australia have Minor Use Permits from APVMA in place for 2021 to help growers with disease control and these are shown in the table below along with all the current registered products. It is particularly important to observe all the conditions set out in these permits for use in lentils as they are grown for human consumption markets, and market access depends on strict delivery standards and residue limits. There is no secondary market for lentils if these standards are not met.

Effective fungal disease control is based on protection of plants rather than curing infections. Assess the disease risk to your crop including distance to last season’s stubble, crop rotation, disease resistance of the variety sown and forecast weather events.  The first fungicide application might be applied as early as necessary to minimise the establishment of the disease. Additional applications may be required if conditions favour disease. The environmental conditions will determine how many fungicide applications are required.

Fungicides remain effective for approximately 10–14 days under ideal environmental conditions for disease development. However, some newer chemistries have been shown to last up to a month. Keep in mind that all new growth after spraying is unprotected. Timing of fungicide applications is critical. An application in advance of a rain front provides maximum protection. Delaying application until after a rain front reduces efficacy significantly. With high levels of inoculum in many paddocks after the wet season in 2020, a protective fungicide application soon after crop emergence may be required. Close monitoring for early symptoms will be needed to give good disease management.

The need for repeated fungicide applications depends on the growth stage of the crop, the time since the last fungicide application and the likelihood of further conditions favouring disease development. Unprotected crops may be quickly defoliated and destroyed by the infection. Under favourable disease conditions, varieties that are susceptible to AB will require multiple sprays through the season, while varieties with moderate susceptibility to AB will require at least 3-4 sprays over the season. The choice of fungicide is less important than the timing, but when multiple sprays are required during the season it is critical to rotate different products and modes of action to preserve the effectiveness of all the fungicide choices. Follow this link for advice on maintaining fungicide efficacy for the grain industry.

Seasonal Conditions in 2021

After a bumper season in 2020 that produced record yields in many areas of NSW, Victoria and South Australia, rainfall has been variable over summer in many regions. NSW and southern Queensland have had good rainfall over summer that has given full soil moisture profiles. Victoria and South Australia started with dry conditions for sowing winter crops but have recently received adequate rain to get crops germinated. In Western Australia conditions have been very favourable for sowing crops and regular rain events have followed. This season will be favourable for many diseases as we head into spring. Many of these diseases need only limited moisture to infect crops (heavy dew – or fog may provide enough moisture), so monitoring needs to be continued through the different growth stages of the crop. With good access for ground sprayers this year, allowing for high water rates and canopy penetration, timely fungicide application will give the crop the best chance of a high yield.

For more detailed information on disease management: 

• Lentil: Integrated disease management
• CropPro lentil disease manual
• Fungicide resistance in grain crops (including pulses)

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  Botrytis affecting a susceptible variety (W. Hawthorne)

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  Botrytis on lentil pod (W. Hawthorne)

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  Ascochyta on lentil leaves (J Davidson).

Minor Use Permits for fungicide on lentils

• PER81406 Captan (M4) / Ascochyta blight, chocolate spot, grey mould / Current to 30-Sep-2023

Fungicides registered for disease control in lentils

Lentil Foliar Fungicide	Trade Name example	Ascochyta blight	Botrytis grey mould	WHP Harvest
Chlorothalonil 720 (M5)	CC Barrack 720	1.0 to 2.0 L/ha	1.0 to 2.0 L/ha	14 days
Mancozeb 750 (M3)	Dithane SC	1.0 to 2.2 L/ha	1.0 to 2.2 L/ha	28 days
Mancozeb 420 (M3)	Penncozeb SC	1.8 to 3.95 L/ha	NR	28 days
Carbendazim (Group 1)	Spin Flo	NR	500 mL/ha	28 days
Captan 900 (M4)	CC Captan 900	Permit 1.1 kg/ha	Permit 1.1 kg/ha	14 days
Captan 800 (M4)	CC Captan 800	Permit 1.25 kg/ha	Permit 1.25 kg/ha	14 days
Azoxystrobin 120 (Group 11) + Tebuconazole 200 (Group 3)	Veritas	750 mL to 1.0 L/ha	750 mL–1.0 L/ha	28 days
Azoxystrobin 200 (Group 11) + Cyproconazole 80 (Group 3)	Amistar Xtra	400 to 600 mL/ha	400–600 mL/ha	56 days
Metiram700 (M3)	Polyram DF	1.0 to 2.2 kg/ha	1.0 to 2.2 kg/ha	42 days
Procymidone (Group 2)	Sumislex	NR	500 mL/ha	21 days
Prothioconazole 150 (Group 3) + Bixafen 75 (Group 7)	Aviator XPro	400 to 600 mL/ha	400 to 600 mL/ha	N/A Cannot apply after early flowering

Many of the Minor Use Permits have short term expiry dates (e.g. 30/11/2022) 

NR = Not Registered      NA = Not applicable when used as directed. 

Read the Label As with any chemical application, care should be taken to observe all the label conditions for each product. Some label advice is different for each state or region, so for best results, it is important that this is followed. Many of our pulse crops are exported for human consumption, so market access is dependent on having the product free of chemical residues. Australian has a reputation for providing clean and safe produce so it is vital that this is maintained by using chemicals according to regulations. All permits have label recommendations for use rate and withholding periods (WHP) that must be observed so grain will comply with Maximum Residue Limits (MRL) allowable for market access.

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Last updated: 9 July 2021