DOI: 10.5061/dryad.q2bvq83st
title: From weeds to natural enemies: Implications of weed cultivation and bio-pesticides for organic onion production

description: Weed management is challenging for vegetable crops highly sensitive to
 weed competition, such as onions. Thrips (Thysanoptera: Thripidae) are
 major insect pests of onion, causing damage through feeding, and vector
 bacterial pathogens causing rot. Both thrips and their associated
 pathogens are known to survive on many weed species in onion growing
 regions. Combining weeding with bio-pesticides may synergistically manage
 thrips and disease by reducing disease prevalence and indirectly
 increasing onion yield. However, disturbances from weeding may negatively
 impact natural enemies. We estimate the effects of organic weed management
 and bio-pesticides on weed density, thrips and natural enemy activity,
 disease severity, and yield. The experiment was a randomized complete
 block design, with four replications of each weeding (control, tine-weeded
 2x, tine-weeded 4x, and hand-weeded) and bio-pesticide (control, OxiDate
 2.0, Serenade) combination. Arthropods were monitored using yellow sticky
 cards, and weed counts, marketable yield, and bulb rot prevalence were
 estimated. Hand-weeding resulted in the lowest weed density and thrips
 abundance. Additionally, hand-weeding produced 9x higher yield compared to
 all other treatments. Significant interactions were observed between
 tine-weeding and bio-pesticide treatments. Natural enemy abundance was
 slightly negatively impacted by weeding, dependent on year. DNA
 metabarcoding results show high parasitoid diversity in onion systems and
 strong reads for multiple genera containing important known biological
 control agents. Our study suggests hand-weeding is necessary in the
 southeast for maximum onion yield. Future research should focus on
 exploring the impact of management on natural enemy communities in onion
 systems at a large scale.
description: # From weeds to natural enemies: implications of weed cultivation and
 bio-pesticides for organic onion production
 [https://doi.org/10.5061/dryad.q2bvq83st](https://doi.org/10.5061/dryad.q2bvq83st) ## Description of the data and file structure Three datasets are provided in in relation to the manuscript: Two datasets for overall data for 2019/2020: 'onion19.dat.csv' for data collected in 2019, and 'onion20.dat.csv' for 2020. The third dataset is for specific yield data for 2019: '2019weedyielddis2.csv' -Columns present the following are represented in the onion#.dat.csv files: plot- plot number year-year of study cultivation- cultivation treatment as specified in the manuscript bactericide - bactericide treatment as specified in the manuscript onS,LSC, HT, CEP,WR= weed categories sampled as specified in the manuscript medium, jumbo, colossal= mass of sizes of onions by plot, then later this was converted to kg/ha Ncenterrrot,Nsrskin=scoring for disease observed, and TotOn = total number of onions scored for disease Natural enemy predators data columns = counts of natural enemies and then total | Geocoridae | Anthocoridae | Carabidae | Staphylinidae | Syrphidae | Spider | Coccinellidae | Predators | | :--------- | :----------- | :-------- | :------------ | :-------- | :----- | :------------ | :-------- | PW=parasitoid wasps total thrips = counts of thrips -Columns present the following are represented in the '2019weedyieddis2.csv': plot- plot number block-grouping of plots and treatments in design year-year of study cultivation- cultivation treatment as specified in the manuscript bactericide - bactericide treatment as specified in the manuscript medium-kilograms of medium sized onions in plot jumbo-kilograms of jumbo sized onions in plot yieldtot-total yield of both onion sized combined within plots kghamed-kg/ha of medium sized onions estimated to scaled up to hectares kghajum-kg/ha of jumbo sized onions estimated to scaled up to hectares