#2003 The color photograph is of a field of cotton. The photograph is divided to depict two different crops, which are distinguishable by color.
The photograph of a cotton field is graphically organized into four areas. On the left are plants that have cotton growing on them, and on the right the plants are barren. Along the horizon line at the back of the composition is a line of trees, and above that, the sky.
The effect of the close cropping of the photograph to this particular section of the field is enhanced by the dramatic differences in color.
On the right, the plants are mostly brown and rough looking, with darker reddish spots throughout. The different textures also serve to enforce a comparison.
2 Build on Your Observations
The point of view of the photograph, with the field dramatically receding into the distance, emphasizes the large size of the field.
The graphic composition is visual confirmation of what we read in the caption and metadata, which tells us the photograph was made in Australia. It shows a field sprayed with Bacillus thuringiensis (Bt), a spore-forming bacterium that produces crystals protein (cry proteins), which are toxic to many species of insects, and an unsprayed field. Bt is a naturally occurring bacterial disease of insects. Cotton crops are particularly attractive to such insects as cabbage loopers, and this is one of the insects that can be controlled with Bt.
3 Make Inferences
4 Formulate Further Questions
How does Bt work to control insects?
Are there other naturally occurring spores like Bt that scientists use to control insects?
Is Bt only effective in certain regions, or is it used throughout the world?