December 18, 2021
Vegetable Trials Update
By David Townley, Agrii Agronomist/Technical Support
Climate change appears to be delaying our cold winter period later into each year, leaving us with warmer and wetter autumns which provides ideal conditions for the develop of diseases of our vegetable crops. Vegetable growers currently rely on a combination of crop rotation, inherent resistance genetics within crop plants, plus justified use of fungicides to ensure our vegetable crops remain free from diseases.
Conventional fungicide chemistry is facing regulatory challenges as each active substance works its way through the re-approval processes. For the future, this may possibly leave fewer effective fungicide options for vegetable crop growers to protect their valuable crops from various diseases.
One of the main objectives of Agrii vegetable crop trials work is to investigate alternative or new control options when existing chemistry is lost due to revocation. This year we have been investigating two new fungicides for the control of diseases in brassica crops.
Both these fungicides have proved highly effective for controlling brassica ringspot, powdery mildew and light leaf spot. We are encouraged that these new conventional fungicides control light leaf spot, as this is one of the most troublesome diseases for Brussels sprout crops.
We are also in the process of investigating a range of bio-fungicides in our vegetable trials work. Bio-fungicides encompass various agents, such as fungi or bacteria with disease suppressing properties, or naturally derived substances extracted from plants which suppress disease. Our trials have identified bio-fungicides that are highly effective for the control of powdery mildew of cucurbit crops, almost as good as our conventional fungicide options.
We have more trials currently running investigating bio-fungicides for the control of diseases in brassica crops. Our initial findings suggest they are not as efficacious compared to existing conventional fungicides, but this does not deter us from continuing further investigations with them, as part of the trials process is to gather information on application timing or application technique to achieve optimum disease control performance.
Our next step is to investigate and develop disease control programmes integrating bio-fungicides with conventional chemical fungicides to achieve adequate season long disease control, which adheres to the application limits for each product.
We must learn how to use bio-fungicides, as they will become a key component for our future Integrated Pest Management programs for disease control in vegetable crops.