Seed Treatments for Vegetable Crops

Flashcards about seed treatments to control seedborne fungal pathogens of vegetable crops

What is the primary way seedborne fungi infect vegetable crops?

The pathogen is already present within or on the seed surface, causing seed rot and seedling damping-off.

What benefits do seed treatments offer in managing plant diseases?

They prevent plant disease epidemics caused by seedborne fungal pathogens and reduce the need for foliar fungicide applications.

Why is there a growing interest in alternative methods to fungicides for seed treatment?

Due to the non-target environmental impact of fungicides and the development of pathogen resistance.

Name three types of alternative seed treatments.

Physical treatments, biopesticides (plant extracts, natural compounds), and biocontrol agents.

What is a key consideration for organic farming regarding seeds?

Seeds should be produced under organic farming conditions.

What factors influence the success of a seed treatment?

The effectiveness of the compound, the degree of internal seed infection, the amount of inoculum, and the potential phytotoxicity of the treatment.

Define seed disinfestation.

The control of spores and other forms of disease organisms on the seed surface.

Define seed disinfection.

The elimination of a pathogen that has penetrated the living cells of the seed and become established.

Define seed protection.

The application of a treatment to protect the seed from seedborne and soilborne disease organisms, preventing seed rot and damping-off.

How have newer systemic fungicides improved upon older inorganic compounds?

They pose less risk to crops, animals, and the environment due to their ready degradation by soil microorganisms.

What are the three kinds of physical seed treatments mentioned?

Hot water, hot air, and electron treatments

What is the mechanism of thermotherapy?

Thermotherapy inactivates or kills the pathogen, while it leaves the host tissue viable.

What is a key consideration when using aerated steam or electron seed treatments?

Pretests with germination assays are necessary to determine the optimum treatment for a given seed batch.

What is the primary focus of integrated pest management regarding seedborne diseases?

To provide more environmentally sound and economically feasible alternatives for disease management.

Name three essential oils with antifungal activities

tea tree, clove, peppermint, rosemary, laurel, oregano and thyme oils.

What is seed priming?

A hydration treatment that includes the application of osmotic stress to seeds prior to drying-back to improve emergence.

What determines the different spatial colonisation patterns of microorganisms on seeds?

The physical conformation of the seed coat (texture and ornamentation).

What is a potential drawback of fungicide treatments on the rhizosphere?

They can alter the metabolic profiles of the culturable rhizosphere bacterial communities, unlike BCAs.

What are PGPRs?

Plant-growth-promoting rhizobacteria: free-living bacteria that colonize the rhizosphere and improve plant growth.

Why are sporulating gram-positive microorganisms advantageous in biocontrol?

They can be formulated readily into stable products such as a dry powder through their heat-resistant and desiccation-resistant spores.