Pallidosis is a disease of strawberry identified in 1957 with an unknown etiology. Two previously uncharacterized viruses in strawberry, Strawberry pallidosis associated virus (SPaV) and Beet pseudo-yellows virus (BPYV), have been found associated with disease symptoms. The complete nucleotide sequence of both viruses was determined and molecular detection protocols developed. In addition, an immunological tissue blot assay was developed for SPaV. Phylogenetic analysis of SPaV placed it in the genus Crinivirus, family Closteroviridae, along with BPYV. Transmission studies identified Trialeuroides vaporariorum, the greenhouse whitefly, as a vector of SPaV, while the virus was not transmitted by pollen or seed. The geographic distribution of both SPaY and BPYV in the United States was examined. Two ilarviruses of strawberry were investigated. Tobacco streak virus (TSV) is the type member of the genus Ilarvirus, family Bromoviridae, and can cause severe yield losses in small fruit crops. Sequence and phylogenetic analysis of 15 "TSV" isolates from Fragaria and Rubus revealed that they are homogeneous and represent a new virus species designated as Strawberry necrotic shock virus (SNSV). Nucleic acid-based protocols failed to identify any plants of the study infected with TSV an indication that the virus may not be a pathogen of Fragaria and Rubus. Fragaria chiloensis latent virus (FC1LV) is the second member of the genus Ilarvirus that infects strawberry. Previously, the virus had been found only in Chile and although many plants have been tested in North America using a serological test, none was found infected with the virus. A molecular test has been developed and used to confirm the presence of the virus in strawberries along the west coast of North America. Phylogenetic analysis of the coat protein gene of the virus place it in subgroup 4 of the genus along Prune dwarf virus, while it was previously thought to be related most closely to Lilac ring mottle virus and Asparagus virus-2. The role of the newly identified viruses and other viruses infecting strawberry is discussed in association with the strawberry decline disease found to cause severe symptoms and yield losses in both California and British Columbia, Canada. The significance of the work presented in this publication includes: the identification of two viruses associated with strawberry pallidosis disease; the complete nucleotide sequence of two criniviruses, an emerging group of plant viruses adds to the limited knowledge we have about this diverse virus genus; the identification of FC1LV in North America; the identification of SNSV as a distinct virus species which demonstrates the need of further studies on TSV, a virus species that infect a wide range of plant species and may actually be a cluster of diverse species. The high incidence of the pallidosis associated viruses points to the significance of the disease and their role in strawberry decline. The development of fast, sensitive and reliable tests for four strawberry viruses will have an impact to the strawberry industry, since the need for high quality, virus-free plants is essential for a crop that is asexually propagated. / Graduation date: 2004

Strawberry plants (Fragaria x annanasa D.) were grown in drip irrigated plots covered with gray/black plastic mulch at the Campus Agricultural Center, University of Arizona, Tucson, AZ. During the 1993-94 season varieties Chandler and Oso Grande were grown while in the 1994-95 season varieties Chandler and Selva were grown. Crop coefficients to estimate crop evapotranspiration for Chandler were determined on calendar day and growing degree day (GDD) basis. For the harvest period, the crop coefficients ranged from 0.35 for early March to 0.6 for early June. GDD were computed using 6 °C as the base temperature and 26 °C as the upper threshold temperature. Although GDD is useful to estimate water needs, it did not predict the starting date of harvest because other factors such as day length, transplanting date, and chilling period are involved. In the 1994-95 season, dry, medium and wet irrigation treatments were established for the Chandler. The well irrigated plants yielded 328 g/plant, equivalent to 21.2 metric tons/ha. The dry treatment received 33 % less water than the medium treatment and resulted 25% less yield. There were no statistical differences in yield between the medium and wet treatments, although the wet treatment received 33% more water than the medium treatment. The Oso Grande and Selva were tested and they yielded 46 and 22% less than Chandler, respectively. The harvest period extended for 70 to 100 days and premium size berries were produced during the first half of the harvesting season.

Graduation date: 1958

Graduation date: 1972

Thesis(M.S.)--Auburn University, 2006. / Abstract. Vita. Includes survey instruments. Includes bibliographic references.

Thesis (M.S.)--University of Wisconsin--Madison, 1962. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 77-83).

No description available.

The objectives of this project were to evaluate the efficacies of electrolyzed oxidizing (EO) and ozonated waters as antimicrobial agents for enhancing the microbiological safety of fresh strawberries (Fragaria x ananassa). The influence of sodium chloride (NaCl) concentrations used for preparing EO water was evaluated on their bactericidal activities against naturally occurring aerobic mesophiles on strawberries with a contact time of 5, 10, or 15 min. EO water and ozonated water containing about 1.90 ppm ozone were evaluated and compared with sodium hypochlorite (NaOCl) solution on their capabilities to inactivate and control the growth of Listeria monocytogenes and Escherichia coli O157:H7 inoculated onto strawberries stored at 4 ± 1 °C for up to 15 d, respectively. Post-treatment neutralization of fruit surfaces by washing was also investigated. More than 2 log₁₀ CFU/g reduction of mesophilic aerobic bacteria was achieved in samples washed for 10 or 15 min in EO water prepared from 0.10% (w/v) NaCl solution. Bactericidal activity of treatment solutions against L. monocytogenes and E. coli O157:H7 was not affected by post-treatment neutralization, and their effectiveness against both pathogens in whole fruit tissues did not significantly increase with increasing exposure time. The EO water had an equivalent antibacterial effect as compare with NaOCl in eliminating L. monocytogenes and E. coli O157:H7 on whole strawberry tissues. Fruit surfaces washing with distilled water resulted in 1.90 and 1.27 log₁₀ CFU/ml of rinse fluid reduction of L. monocytogenes and E. coli O157:H7, respectively, whereas ≥ 2.60 log₁₀ CFU/ml of rinse fluid reduction of L. monocytogenes and up to 2.35 and 3.12 log reduction of E. coli O157:H7 were observed on fruit surfaces washed with EO water and NaOCl solution, respectively. However, EO water and NaOCl solution treatments did not exhibit a higher microbicidal activity than water treatment during refrigeration storage. The ozone treatment on inoculated strawberries was not remarkably effective in removing and eliminating pathogens on the whole fruit tissues, but the populations of L. monocytogenes and E. coli O157:H7 were significantly decreased after ozone treatment regardless of the exposure time. The number of L. monocytogenes and E. coli O157:H7 on fruit surfaces was decreased by 2.17 and 2.02 log₁₀ CFU/ml of rinse fluid, respectively, after washing with ozonated water for 10 min. / Graduation date: 2008

Call number: LD2668 .T4 1957 A86 / Master of Science

No description available.