Self-study
P1
Sometimes there is no more effective means of controlling an agricultural pest than giving free rein to its natural predators. █ ████ ██ █████ ██ ███ ████████ █████ █ ████ █████ ██████████ ███ ██ ███████████ ██████████ ██ █ █████████ ████ ██ ███ █████ █████████████ ███
Intro topic ·
Controlling cyclamen mites using Typhlodromus mites
Problem ·
Infestation of strawberry plants by cyclamen mites
Solution ·
Typhlodromus mites
Attack in second year of infestation, when cyclamen mite populations reach damaging levels
P2
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Introduce explanation ·
Several reasons why Typhlodromus is a good solution
Reason 1: Voracious appetite
Reason 2 ·
Typhlodromus population grows as quickly a cyclamen's
Both reproduce by parthenogenesis
Reasons 3 and 4 ·
Reproductive timing and alternative sources of food
Reason 3: Typhlodromus only reproduces when cyclamen prey is available.
Reason 4: Typhlodromus has other food sources, allowing it to survive when cyclamen mites are scarce.
Draw similarity ·
Typhlodromus is similar to other predators that control prey
Because of reasons 1-4
P3
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Support solution ·
Experiments correlate presence of Typhlodromus with lower cyclamen populations
P4
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Implications of experiment ·
Pesticide use can cause more harm than good...
...if pesticides kill predators like Typhlodromus
Reinforce implications ·
Where pesticide (parathion) used, Typhlodromus absent and cyclamen populations higher
Again, correlation between presence of Typhlodromus and lower cyclamen populations
Passage Style
Problem-analysis
Single position
26.
Which one of the following ██████ ██ █████ ████ ██████████ ███ ████████ ████████ █████████ ███ █████████ █████████████ ██ ███ ███████████ █████ █████████ █████ █████████ ██ ███ ████████
a
The individual Typhlodromus █████ ████ ████ ███ ███████ ████████████ ████ █████ █████████ ████ ███ ███ ████████ ██████ ██ ████ ███ ████
It’s not clear how learning some facts about individual T-mite egg-laying rates can help show the practicality of using T-mites.
b
The insecticides that ███ █████████ ████ ███ ████ ███████ ██ ██████████ ██████ ████ ████ █████████ ███ ████████████ ███████ ██ ██████
This, if anything, is something that goes against the practicality of T-mites. The typical insecticides used on strawberry plants will end up killing the T-mites.
c
In areas in █████ ██████████ ██████ ██████ ████████ ██ ████████ ██████ ███████ ████ ██ ██ █████ ███ ██████████ █████
This doesn’t strengthen, because T-mites have seasonal synchrony with C-mites. So the length of the winter doesn’t make T-mites more or less practical to use. T-mites will simply be synchronous with C-mites regardless of the length of winter.
d
Typhlodromus are sometimes ██████ ████ ██ ███████ ███████ ██ █████ ████ ██ ██████ ███████████ ██ ██████████
Learning that another mite kills T-mites doesn’t help establish the practicality of T-mites. It would be more helpful to learn that T-mites don’t have predators that could decrease their population in the areas we want them to control C-mites.
e
Typhlodromus easily tolerate ███ ████ █████ ██ ████████ ██████████ ████ ██████████ ██████ ███
This strengthens the practicality of T-mites by showing that they can actually be generally used on strawberry plants. Imagine if (E) were not true — in that case, T-mites wouldn’t be as practical as a solution for C-mites, because they couldn’t survive in all the places strawberry plants are used. By helping to establish that they can survive where strawberry plants are used, (E) provides a reason for the practicality of T-mites as a way to control C-mites.