This is an extract from the Water Gardeners Journal from 2006 about the
biological control of pests at The Royal Botanic Garden Edinburgh.
Biological Control of Pests
at the Royal Botanic Garden,
Edinburgh, Scotland
by Pat Clifford, Senior Horticulturist
Click images to enlarge
At the beginning of the 2006 season our Nelumbos nearly
succumbed to a nasty infestation of the red spider mite
(Tetranychus urticae). A solution had to be found fast. At RBGE
the policy is to use biological control whenever possible. This is
particularly important when dealing with ponds, which may or
may not contain fish. In this case we opted for the Fast-Action
Mite Predator (Phytoseuilus persimilis).
They arrive in a small bottle
which contains 400 adults
packed in vermiculite which are
released onto the affected
plants. The tiny 0.5mm (0.02")
females then begin feeding and
laying eggs, up to 60 at a time,
in the spider mite
concentrations.
Above and left, red spider mite
infestation.
Below, after treatment.
These voracious predators have to hunt and eat constantly to
survive. Their huge appetites in fact contribute to their own
demise - when they've eaten all the spider mites they starve. If
another infestation occurs more need to be added. The predators
need to be in conditions with a minimum temperature of 16°C
(60°F) and high relative humidity of 60-90%, which is ideal for
our tropical glasshouses. They are unbelievably fast acting and
effective.
Read the information and answer the questions on the other side
Answer all these questions in your jotter
1. What is the name of the pest species involved?
2. What is the name of the plant it was damaging?
3. What is the name of the control species that the Botanic Gardens used?
4. Why could they not use chemicals?
5. How do the control species get to the Botanic Gardens?
6. How many of the females would fit along 1cm?
7. How many eggs do they lay at a time?
8. How do the predators contribute to their own downfall?
9. What are the growing conditions for the predators?
10. Predict what would happen to the predators if the heating system in the
glasshouse failed over a weekend when the Botanic Gardens were shut?
For the next part you will need to go online.
Draw a picture of both the predator and its prey from this example of biological
control