Increasing crop field size does not consistently exacerbate insect pest problems.

Area of Science:

• Agricultural Ecology
• Ecosystem Services
• Pest Management

Background:

• Increasing farm biodiversity can enhance ecosystem services, including natural pest control.
• Agroecological literature often assumes larger monocultural fields exacerbate pest impacts.
• Theoretical models present uncertain predictions regarding field size and pest densities.

Purpose of the Study:

• To empirically investigate the relationship between crop field size and arthropod pest densities.
• To quantify the impact of field size on pesticide applications and crop yield.
• To evaluate the validity of the assumption that larger fields disrupt natural pest control.

Main Methods:

• Conducted a broad survey across 14 pest species, 5 crops, and 20,000 field-years of data.
• Quantified pest densities, pesticide applications, and crop yield in relation to field size.
• Correlated pest responses to field size with responses to landscape crop simplification.

Main Results:

• No consistent evidence that larger fields lead to worse pest impacts across all species.
• Pest severity was independent of field size for 9 out of 14 species.
• Larger fields reduced pest problems for 4 species; only 1 species showed increased pest severity with larger fields.

Conclusions:

• The assumption that larger field sizes consistently disrupt natural pest control is not supported by empirical data.
• Pest responses to field size and landscape simplification appear driven by shared ecological processes.
• Findings challenge conventional agroecological wisdom regarding field size and pest management.