Lentils – Pre Canopy Closure Fungicide
Very high lentil prices early in 2016 and high forward pricing for the 2016/17 harvest has lead to an increased lentil planting for this season. Lentils can be a challenging crop to grow but if the stars align they can also be very profitable. With many new growers for this season it is important to be aware of some of the traps that can come with growing lentils. They are a crop where you cannot be frugal with inputs as the consequences can be severe, for example the management of Botrytis Grey Mould.
Botrytis Grey Mould is a fungal disease and poses a significant risk with growing lentils. Management includes time of sowing, row spacing, variety resistance, and a vigilant fungicide program for non-resistant varieties. Ideally lentil varieties with good resistance to BGM would be grown however sometimes varieties have attributes that trump BGM resistance such as Bolt where extra salt and boron tolerance and high yield under drought conditions mean accepting a high fungicide regime if the spring is favourable.
The first fungicide for BGM is made just prior to canopy closure (NOT after canopy closure). This is because once the canopy closes getting fungicides to the base of the plants where the fungal disease will develop first is extremely difficult. In addition air flow through the canopy reduces significantly with canopy closure and with moisture and warm temperatures humidity increases and BGM can develop.
For disease to become an issue you need three things, a host, the disease present and the environmental conditions. Until the canopy closes you will be unlikely to have conditions for BGM to develop due to airflow. Depending on the variety you may have a susceptible host or you may have good resistance (e.g. Jumbo2), but remember ALL varieties need the pre-canopy closure fungicide as under enough pressure resistance breaks down. If the variety is susceptible and the canopy is closed BGM can quickly establish so make sure fungicides are preventative as they work a lot better before the disease establishes.
The fungicide of choice for the pre-canopy closure spray is normally Carbendazim, it is now relatively cheap however you can only use it twice a season due to residue and resistance issues. So don’t waste it by going out too early. Coverage is very important which means good water rates, preferably 80-100L/ha and if your droplet spectrum is on the coarser side your can add 0.1%wetter 1000 to increase the amount of fines and coverage.
Unless a variety has complete resistance follow up fungicides will be required if environmental conditions are conducive. BGM kills lentil plants by cutting their flow of nutrients and water up the stem. With current cereal prices, pulses, especially lentils will be very important for profitability this season so it will pay to be on the ball.
The Smart Agro