Necrotrophs, Biotrophs and Hemibiotrophs and their controls

Necrotrophs, biotrophs, and hemibiotrophs are terms used to classify different types of plant pathogens based on their interactions with host plants. Understanding these classifications is important for devising effective strategies to control these pathogens. Here’s a brief overview of each group and control strategies:

1. Necrotrophs:

• Definition: Necrotrophs are pathogens that kill host cells and tissues to obtain nutrients from the dead material. They typically secrete toxins and enzymes that cause cell death and decay.
• Control Strategies:
  • Resistant Varieties: Plant resistant cultivars that can limit the spread and damage caused by necrotrophic pathogens.
  • Fungicides: Utilize fungicides to manage necrotrophic pathogens; however, the effectiveness may vary based on the specific pathogen and plant stage.
  • Cultural Practices: Implement good cultural practices, such as proper sanitation, adequate plant spacing, and timely removal and disposal of infected plant material, to reduce disease pressure.

2. Biotrophs:

• Definition: Biotrophs are pathogens that derive nutrients from living plant cells. They establish a symbiotic relationship with the host and often cause chronic infections.
• Control Strategies:
  • Resistant Varieties: Breeding and using resistant plant varieties that can recognize and resist biotrophic pathogens effectively.
  • Biological Control: Use beneficial microbes or predators that can antagonize or compete with the biotrophic pathogen, limiting its growth and spread.
  • Enhanced Plant Immunity: Enhance the plant’s natural defense mechanisms through practices like foliar applications of immune-inducing compounds or beneficial microorganisms.

3. Hemibiotrophs:

• Definition: Hemibiotrophs exhibit a dual lifestyle, starting as biotrophs by establishing a biotrophic phase in the host, followed by a necrotrophic phase where they switch to killing host tissues for nutrients.
• Control Strategies:
  • Integrated Pest Management (IPM): Adopt an integrated approach that combines multiple strategies, including resistant cultivars, cultural practices, biological control, and targeted fungicide applications.
  • Timing of Controls: Tailor control measures to the specific phase of the hemibiotroph. Biotrophic phase control may differ from necrotrophic phase control.
  • Monitoring and Early Intervention: Regularly monitor for symptoms and signs of infection, and intervene promptly when the transition from biotrophic to necrotrophic phase is observed.

General Control Strategies for All Pathogens:

• Crop Rotation: Rotate crops to disrupt pathogen life cycles and reduce disease pressure in the soil.
• Sanitation: Remove and destroy infected plant material to prevent the buildup and spread of pathogens.
• Proper Irrigation: Avoid excessive moisture, as it can create a favorable environment for many pathogens.
• Adequate Nutrition: Maintain proper nutrient levels to ensure plants are healthy and can better withstand pathogen attacks.
• Education and Awareness: Stay informed about prevalent diseases, their life cycles, and appropriate control measures to make informed decisions.

Tailoring control strategies based on the specific pathogen type and understanding their life cycle is crucial for effective disease management and sustainable agricultural practices. Integrated approaches that combine various strategies often yield the best results.

Talk to your OMEX representative today to learn more about the various categories of pathogens that are a threat to your crop and how to control them using a combination of essential nutrient products and fungicides.