Incorporating Native Plants in Insectary Strips to Promote Insect Diversity and Below-Ground Beneficial Microbes in South Texas

Lindsey N. Richards, The University of Texas Rio Grande Valley

Copyright 2023 The Author. All Rights Reserved.

Abstract

Farm edges are generally the most undisturbed areas in a farm with diverse vegetation and can enhance agrobiodiversity and provide crucial food and shelter for wildlife, insects, and soil biota. Planting native wildflowers with the ability to reseed and withstand local climatic conditions for semi-permanent vegetation around farm edges or in between crops has the potential to biologically control pests. To test this, we ran a two-year study and installed three different flowering insectary strips on a certified organic vegetable farm in South Texas during the winter season. The treatments were: 1) a commercially sourced 17-species native wildflower seed mix; 2) sunn hemp (Crotalaria juncea); and 3) weeds that spontaneously germinated. We collected pitfall traps, sticky traps, and blue-vein pollinator traps to capture above-ground arthropods and ran PFLAs to determine the proportions of soil microbes. Our results show that the soil microbial communities were influenced by treatment, location, and time. The middle of the insectary strips had significantly higher fungal-to-bacterial ratios and gram-negative proportions compared to the cash crops. Arthropod communities were influenced by time and location but not treatment. Traps collected later in the season showed fewer pests (main order Hemiptera) and more beneficials (main orders Coleoptera and Hymenoptera) in the middle of the insectary strip compared to the cash crop.