Browsing by Subject "fruit quality"

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    Expanded Use of Hail Netting in Minnesota Apple: Impacts on Insect Pests, Fruit Production, and Natural Enemies
    (2023-08) Nelson, Sally
    The management of apple insect pests in orchards in the United States has historically depended upon broad-spectrum insecticides. Exclusion netting has begun to be adopted by fruit growers across the world to assist with the management of insect pests and to reduce chemical input. In apple, the first exclusion netting system was developed in the early 2000s, and new developments in color, mesh size, and material continue to be made. Hail netting, originally developed to protect pome fruit from hail damage, has begun to be adopted by growers in Minnesota, USA. The potential for hail netting to be used as a dual-purpose management tool, both to protect from hail and exclude key insect pests in Minnesota, is investigated in this study. This research examined the efficacy of hail netting as a pest exclusion tactic and the non-target effects of hail netting on fruit production and the natural enemy community. First, the efficacy of hail netting in reducing pest populations was compared to a commercial grower’s spray schedule in Minnesota. The insecticides used by the grower in 2021 and 2022 were clothianidin, abamectin, novaluron, and acetamiprid. The three insect pests that we monitored for were the codling moth (Cydia pomonella Linnaeus; Lepidoptera: Tortricidae), the apple maggot (Rhagoletis pomonella Walsh; Diptera: Tephritidae), and the red-banded leafroller (Argyrotaenia velutinana Walker; Lepidoptera: Tortricidae). This work was conducted as a two-year field study, with both years showing a significant reduction in pest pressure under the netting. Insecticide application did not significantly reduce pest pressure from any of the three pests. The interaction of netting and insecticide application was found to significantly improve fruit quality at harvest time. Neither netting nor insecticide was found to significantly influence apple yield. Second, hail netting significantly reduced predator family richness and the number of individuals that were caught. The most abundant predator family observed was Anthocoridae, along with Coccinellidae, Formicidae, and Empididae. All of these families were significantly reduced in number inside the netting. The diversity of predator families, evaluated using Simpson’s and Shannon’s diversity indices, was not significantly influenced by the netting or spray treatments. Spray treatments did not significantly reduce the family richness or the number of individual predators caught in any family. The environmental risk of the insecticides used in this study was evaluated using the Environmental Impact Quotient and the Pesticide Risk Tool. The tools had slightly different findings, but overall there was a higher risk to non-target arthropods caused by the neonicotinoids clothianidin and acetamiprid.
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    Investigating Kiwiberry Fruit Quality and Germplasm Suitability
    (2023-07) Wannemuehler, Seth
    Recent years have seen an increase in consumer demand and interest for a diversity of kiwifruit products (Harker et al. 2007; Jaeger et al. 2003; Latocha and Jankowski 2011). As market trends for local produce and consumer interest in diversifying food options increase in the United States, the opportunity to grow local fruit with novel characteristics becomes desirable. This interest has spurred investigation into kiwiberry as a new cold-hardy crop for Minnesota. The name kiwiberry is used to differentiate the species Actinidia arguta and A. kolomikta, which are two berry-sized, pubescence free, cold-hardy kiwifruit, from the fuzzy kiwifruit common in the marketplace A. chinensis (Hastings, 2018; Huang, 2016). Actinidia arguta and A. kolomikta are of particular interest for production in Minnesota as they have been reported to have relative ranges of cold-hardiness appropriate for cultivation in USDA zone 4 (-20 °F to -30 °F) (Lin et al. 202; Sun et al. 2020). Though there is increasing interest in these species, research is still needed to examine suitability of kiwiberry as specialty crops in Minnesota. This research utilized the established kiwiberry germplasm at the University of Minnesota (UMN) containing approximately 306 accessions of A. arguta, A. kolomikta, and their hybrids to address the following objectives: 1) determine consumer willingness-to-pay for kiwiberry; 2) improve curation of North American kiwiberry collections; 3) determine the impacts of harvest timing on fruit quality and storability for accessions of two kiwiberry species (A. arguta and A. kolomikta); and 4) examine whether the climacteric nature of kiwiberry allows for reduced spotted-wing drosophila (SWD) infestation pressure at harvest (as a function of harvest date or fruit firmness) and the subsequent impacts of infestation on fruit quality of two kiwiberry species (A. arguta and A. kolomikta) in the Upper Midwest. Consumers were willing to pay comparable prices for kiwiberries as other berries based on a second-price auction examining four kiwiberry accessions. A total of 262 kiwiberry accessions along with 106 National Plant Germplasm System (NPGS) accessions were fingerprinted using single nucleotide polymorphisms (SNPs) generated with genotyping-by-sequencing (GBS). Identity of 97 accessions were confirmed, of which 36 were previously unknown, and redundant accessions called. Fruit quality traits were observed for eleven known accessions over three years and optimal harvest timing for production was determined for each accession. Harvesting firm fruit was shown to reduce the infestation rates of spotted-wing drosophila (SWD) on fruits. Implications of this work are 1) identification of consumer segments interested in purchasing kiwiberry; 2) improved curation of UMN kiwiberry germplasm for more informed future breeding; 3) recommendations of harvest timing balancing fruit quality and storage; and 4) leveraging the climacteric nature of kiwiberry to reduce SWD infestation.