Title

Weed Diversity Decreases Pest Abundance without Yield Loss

School Name

South Carolina Governor's School for Science & Mathematics

Grade Level

12th Grade

Presentation Topic

Botany

Presentation Type

Mentored

Oral Presentation Award

1st Place

Abstract

Farmers spend much of their time and money managing weeds because they compete with crops but weeds also provide ecosystem services on farms. They introduce plant diversity in a crop monoculture and are important habitats for beneficial insects, providing alternative food resources and refuge from weather and predation. In this experiment we measured effects of weed diversity on the density of predators in eggplant crops and on biological control of pests and weed seeds. We manipulated weed density in 10 small plots, performed weed surveys, and sampled pest and predator communities with pitfall traps, visual surveys, and vacuum collection. We measured biological control of weed seeds and insect prey as well and collected eggplant yield data to measure potential costs of weed tolerance. In weedy plots we found more predators, fewer pests, and observed higher rates of consumption of seeds than in weed-free plots. However, pupae consumption between the two treatments were not statistically different. Importantly, there was no yield cost to weed tolerance in our system. While weeds do not always lead to reduced crop production, the biodiversity they provide can encourage pest control services in agroecosystems.

Location

Founders Hall 111 B

Start Date

3-30-2019 11:15 AM

Presentation Format

Oral Only

Group Project

No

COinS
 
Mar 30th, 11:15 AM

Weed Diversity Decreases Pest Abundance without Yield Loss

Founders Hall 111 B

Farmers spend much of their time and money managing weeds because they compete with crops but weeds also provide ecosystem services on farms. They introduce plant diversity in a crop monoculture and are important habitats for beneficial insects, providing alternative food resources and refuge from weather and predation. In this experiment we measured effects of weed diversity on the density of predators in eggplant crops and on biological control of pests and weed seeds. We manipulated weed density in 10 small plots, performed weed surveys, and sampled pest and predator communities with pitfall traps, visual surveys, and vacuum collection. We measured biological control of weed seeds and insect prey as well and collected eggplant yield data to measure potential costs of weed tolerance. In weedy plots we found more predators, fewer pests, and observed higher rates of consumption of seeds than in weed-free plots. However, pupae consumption between the two treatments were not statistically different. Importantly, there was no yield cost to weed tolerance in our system. While weeds do not always lead to reduced crop production, the biodiversity they provide can encourage pest control services in agroecosystems.