Factors Affecting Belowground Biocontrol Activity in Urban Gardens and Vacant Lots

FACTORS AFFECTING BELOWGROUND BIOCONTROL ACTIVITY IN URBAN GARDENS AND VACANT LOTS

Priyanka Yadav, Kuhuk Sharma and Parwinder S. Grewal*

Center for Urban Environment and Economic Development, Department of Entomology, The Ohio State University, OARDC, 1680 Madison Avenue, Wooster, OH 44691, USA.

*Corresponding author
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Abstract
Conservation of naturally occurring belowground pest biocontrol services can enhance sustainability of urban landscapes by reducing reliance on toxic and expensive chemical pesticides. Here we identified soil chemical and biological properties that promote belowground biocontrol services in urban gardens and vacant lots slated for urban agriculture in three Ohio cities: Cleveland, Columbus and Akron. Specifically, we quantified belowground biocontrol activity using an in-situ insect baiting technique and assessed soil pH, moisture, cation exchange capacity, soil organic matter, % C, % N, NH4-N, NO3-N, microbial biomass-N, P, K, Ca, Mg, and parameters of nematode community. We hypothesized that belowground biocontrol activity will be positively correlated with soil chemical and biological parameters that promote soil health. We found that the potential belowground biocontrol service was high with mean total percent bait insect mortality in urban gardens and vacant lots in the three cities ranging between 63% and 82%. However, soil factors associated with biocontrol activity were different for different biocontrol agents. Bait insect mortality due to ant predation was associated negatively with soil NH4-N and nematode food web enrichment index but positively with number of omnivorous nematodes and soil moisture. In contrast, bait insect mortality by microbial pathogens was positively associated with the nematode enrichment index and NH4-N, and negatively with the number of omnivorous nematodes and soil moisture. Mortality by entomopathogenic

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