Chapter 8 Self-test questions

. Macrobials (beneficial insects), microbials (microorganisms), and biorationals (compounds of natural origin) are the three main categories of what type of control methods?

Macrocontrol.

Abiotic control.

Biocontrol.

Chemical control.

. Why are macrobials such as predatory mites mainly used only on high value crops such as strawberries, vegetables and flowers?

They tend to be very expensive to use.

They will fly away if you try them in wheat or barley.

Other crops do not have damaging pests that need controlling.

You are not legally allowed to use them in crops such as wheat.

. The use of nematodes to control slugs is an example of a biopesticide that can be used in almost any crop. Why?

The nematodes are already in the soil, so you do not need to add more.

They are not killed by exposure to direct sunlight.

They are easily applied through conventional large-scale spraying equipment.

There are no restrictions on their use.

. Which of the following has been used as a 'natural' insecticide since 1000BC?

Dried horse urine.

Homogenised bird droppings.

Denatured Bacillus thuringiensis.

Crushed chrysanthemum.

. Which of the following are not tools that farmers would use as part of integrated crop management?

Selecting the best seed.

Careful crop rotation with a field over many years.

Stubble burning to reduce the number of fungal spores in the following crop.

Chemical control where absolutely necessary.

. How does Bacillus thuringiensis kill an insect?

The bacteria spores are breathed in via the spiracles, paralysing the insects' lungs.

Bacterial spores germinate on the insect abdomen and gradually rot the insect.

The bacteria get into the insect blood supply or haemolymph and multiply to the point where they block the flow of blood.

Protein toxins produced by the bacteria paralyse the insect's digestive tract-effectively starving it to death.

. Which of these is not a beneficial insect?

Aphid.

Ladybird.

Lacewing.

Honey Bee.

. What is the source of the majority of bio-antimicrobials?

Sea water.

Soil.

Plants.

Fungi.

. What is a biostimulant?

Crop protection products using beneficial insects, microorganisms or natural products.

Natural compounds which improve athletic performance.

A microorganism or compound of natural origin which helps promote stronger, healthier, and more robust crops.

A chemical that stimulates biological systems.

. Bacillus thuringiensis is a widely used example of a…

Biorational.

Biostimulant.

Bio-antimicrobial.

Bio-insecticide.

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