Ecology and management of sorghum ergot ( claviceps africana)

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Takeallexercise_68e00e105340f4e7811e2d9dc28302be.pdf

AGRO311 Plant Protection

Life history/ecology and pest management

In your assignment, you are asked to review the life history and ecology of a pest organism

and relate this to approaches to management. This exercise will help you to think about how

you can do this, using take-all on wheat as an example. The leaflet supplied provides some of

the information that you would need. Of course for your essay you would track down the

references and get the information from the original sources! There will also be questions that

you cannot answer from the leaflet. For your essay, this would indicate that you need to do

further research.

Life history

What is the source for establishing populations in the crop (i.e. what is the inoculum)?

How does the population establish itself in the crop (i.e. how does infection occur)?

How does the population increase within the crop (a tricky one for a fungus – think in terms

of increase in biomass)?

How does the population maintain itself when the host is absent (i.e. over summer)?

Factors affecting population growth

On which plants can the population increase (i.e. what is the host range)?

How do environmental conditions (temperature and water) affect population increase (i.e.

infection and growth within the plant)?

How do soil physical and chemical properties affect population growth (infection and growth

within plant)?

Factors affecting mortality

What environmental or other factors affect survival over the summer or in fallows?

Interactions with other organisms

What other organisms affect rates of population growth or mortality?

Ecology and yield loss

How do population levels affect the amount of loss from the disease?

How does time of infection (or sowing) affect loss?

How long does it take for mortality to bring populations below economic thresholds (trick

question)?

Informed management

Which part of the life cycle has the greatest effect on the amount of disease in a crop?

Which part of the life cycle gives the best opportunities for management?

What is the most important management practice? Considering the life history and ecology,

why is this most effective?

What factors that you have looked at above need to be taken into consideration for this

management practice?

You should spend a few moments thinking about why other management tools work or not,

based on the insights you have gained on the ecology of the disease.