Infection during flowering and podding may result in dry, rotted pods with small, shrivelled seeds. Infected seed downgrades the grain harvested and is also not suitable for planting because BMG is also seed borne.
Botryis grey mould activity in SA lentil crops
by Mary Raynes
Conditions are currently (early Sept 2015) favourable to botrytis grey mould (BGM) activity in lentil crops across South Australia.
Key message
- It is extremely wise to protect high value lentil crops from BGM.
- Lentil crops that have been affect by frost will be more susceptible to BGM infection.
- BGM is very difficult to control in lentil crops post canopy closure.
- Dense canopies, which retain humidity, will favour disease development.
- PBA Hurricane and PBA Flash are classified as moderately susceptible (MS) to BGM.
- Lentil crops with BGM will require ongoing fungicides sprays while the weather remains showery.
- In dry and warmer conditions BGM spread will slow down.
Treatment
Frosted lentil crops
Lentil crops that have been frosted (severity will vary from crop to crop) will be more susceptible to BGM as the pathogen will rapidly infect the damaged foliage.
Extra monitoring is required to estimate the potential need for sprays every 2–3 weeks, depending on rain events. Carbendazim and procymidone are the preferred products as they have the best efficacy against BGM.
Pre canopy closure Apply fungicide pre canopy closure to provide the crop with the best protection against the fungal disease. The aim is to apply the fungicide (carbendazim) to the base of the plants to stop the BGM from developing in the micro-climate near ground level under plant canopy.
Post canopy closure Post canopy closure in lentil crops it is extremely difficult to get fungicides down to the site of action (disease) under in the bulk of the canopy, and all fungicides will be less effective. Fungicides applied after canopy closure will protect the upper canopy from infection.
Experience from 2010 in Queensland of BGM on desi chickpea, found both mancozeb and Captan helped to supress BGM so long as canopy closure sprays were applied. Without canopy closure sprays, all products are less effective.
Monitor and apply fungicide every 2–3 weeks, prior to a rain event while ever rainy conditions persist. The aim is to protect any new growth and also to protect flowers, pods and seeds from disease activity.
Pulse Australia is aware that the supply of carbendazim and procymidone are all but being exhausted across some areas of the southern region. Talk to your reseller and advisor to determine what is available in your area. Pulse Australia obtained permits for an additional product (Captan) for the control of botrytis grey mould in lentil. This product may not be the first choice for efficacy against BGM but does have some activity.
Captan (800 & 900 g/kg Captan products) APVMA Permit PER81406
This permit is in force from 28 July 2015 to 30 September 2018 for use in chickpea and lentil for the control of ascochyta blight and botrytis grey mould Use rates are 1.25 kg/ha (800 g/kg products) and 1.11 kg/ha (900 g/kg products).
Acknowledgements
Dr Jenny Davidson, Senior Plant Pathologist, SARDI Helen Richardson, Plant Pathologist, DED JTR, Horsham Vic Southern Pulse Agronomy Team
Further information
http://www.croppro.com.au/crop_disease_manual/ch08s02.php http://agriculture.vic.gov.au/agriculture/pests-diseases-and-weeds/plant-diseases/grains-pulses-and-cereals/botrytis-grey-mould-of-lentil http://www.pulseaus.com.au/storage/app/media/crops/2012_SPB-Lentil-disease-management.pdf