Embora o congelamento apresente vantagens em relação a outros métodos de conservação de alimentos, o mesmo causa alterações sensoriais, principalmente em produtos de origem vegetal. O morango, uma fruta muito apreciada e com formas variadas de consumo, tem comportamento sazonal e apresenta como fator limitante para o congelamento sua estrutura frágil e sensível ao processo, o que causa alterações sensoriais. Tais alterações podem ser minimizadas com a incorporação de crioprotetores, como a trealose, um dissacarídeo que vem se destacando pelo seu efeito crioprotetor em produtos congelados e desidratados. O principal objetivo deste trabalho foi verificar o efeito crioprotetor da trealose incorporada através da impregnação a vácuo em soluções de diferentes concentrações (100, 300 e 500 g/L) em morangos submetidos ao congelamento e descongelamento. As condições de impregnação foram de 5 min, aplicando pressão de -650 mmHg e 10 min de tempo de relaxamento. As alterações provocadas pelo processo de impregnação bem como a verificação do efeito crioprotetor da trealose foram identificadas através de análise de cromatografia líquida de alta eficiência (High Performance Liquid Chromatography- HPLC), análise colorimétrica, análise de textura, determinação do teor de sólidos solúveis, determinação do teor de umidade e perda de massa (perda por gotejamento). Os resultados mostraram que a concentração da solução de trealose exerce influência significativa no teor de umidade, teor de sólidos solúveis e teor de trealose. As amostras tratadas com soluções mais concentradas não sofreram desidratação após descongelamento. O teor de trealose, após descongelamento, permaneceu constante em todas as amostras tratadas. Todas as amostras tiveram a mesma perda de massa após descongelamento (perda por gotejamento), porém a composição da massa diferiu entre elas. Amostras tratadas com a solução mais concentrada perderam sólidos enquanto que as amostras tratadas com a menos concentrada, perderam água. Na análise de textura, a introdução da trealose não influenciou a força máxima de pico nas amostras impregnadas. Após descongelamento, todas as amostras, exceto a tradada com solução de 500 g/L, sofreram amolecimento. A parte externa dos morangos não sofreu alterações de cor devido à introdução da trealose nem devido ao congelamento e descongelamento. Na parte interna dos frutos, ocorreram variações no parâmetro L* devido à impregnação e no parâmetro b*, devido ao congelamento e descongelamento. / Although freezing offers advantages to others food conservations process, it causes sensorial changes, mostly in vegetables products. The strawberry, a quite appreciated fruit, shows different ways of use, has seasonal behavior and is limited to freezing due the sensorial changes caused by its fragile structure to freezing process. These sensorial changes can be minimized by the incorporation of cryoprotectors, as trehalose, that is known by its cryoprotector effect during freezing and dehydration. The aim of this work was to verify the trehalose cryoprotector effect in frozen and thawed strawberries introduced by vacuum impregnation with different solutions (100, 300 and 500 g/L). The impregnation conditions were 5 min of applying pressure of -650 mmHg and after atmospheric pressure was restored, the sample was maintained within the solution for 10 min (these conditions were obtained from previous experiments). The alterations caused by the vacuum impregnation and the verification of the cryoprotector effect of trehalose were identified by High Performance Liquid Chromatography (HPLC), color analysis, texture analysis, soluble solids content, moisture content and drip loss. The results have shown that concentration of the trehalose solution had a significant influence on the moisture content, soluble solids and trehalose content of impregnated strawberries. The samples treated with more concentration solutions did not dehydrated after thawing. The trehalose content was the same in all treated samples after thawing. All the samples showed the same drip loss due to thawing although the composition of the mass was different among the samples. Samples treated with the most concentration solution lost trehalose while the sample treated with the least concentration solutions lost water. The introduction of trehalose did not affect the maximum peak force of the impregnated samples. The freezing and the thawing process caused the softening of the samples. This effect was not observed on the sample treated with solution of 500 g/L. The introduction of trehalose did not cause significant differences in all color parameters measured on the outside of the strawberries after impregnation and thawing. In the inside of the samples, there were variation in the L* parameter caused by the vacuum impregnations and in the b* parameter caused by the freezing and thawing process.

Embora o congelamento apresente vantagens em relação a outros métodos de conservação de alimentos, o mesmo causa alterações sensoriais, principalmente em produtos de origem vegetal. O morango, uma fruta muito apreciada e com formas variadas de consumo, tem comportamento sazonal e apresenta como fator limitante para o congelamento sua estrutura frágil e sensível ao processo, o que causa alterações sensoriais. Tais alterações podem ser minimizadas com a incorporação de crioprotetores, como a trealose, um dissacarídeo que vem se destacando pelo seu efeito crioprotetor em produtos congelados e desidratados. O principal objetivo deste trabalho foi verificar o efeito crioprotetor da trealose incorporada através da impregnação a vácuo em soluções de diferentes concentrações (100, 300 e 500 g/L) em morangos submetidos ao congelamento e descongelamento. As condições de impregnação foram de 5 min, aplicando pressão de -650 mmHg e 10 min de tempo de relaxamento. As alterações provocadas pelo processo de impregnação bem como a verificação do efeito crioprotetor da trealose foram identificadas através de análise de cromatografia líquida de alta eficiência (High Performance Liquid Chromatography- HPLC), análise colorimétrica, análise de textura, determinação do teor de sólidos solúveis, determinação do teor de umidade e perda de massa (perda por gotejamento). Os resultados mostraram que a concentração da solução de trealose exerce influência significativa no teor de umidade, teor de sólidos solúveis e teor de trealose. As amostras tratadas com soluções mais concentradas não sofreram desidratação após descongelamento. O teor de trealose, após descongelamento, permaneceu constante em todas as amostras tratadas. Todas as amostras tiveram a mesma perda de massa após descongelamento (perda por gotejamento), porém a composição da massa diferiu entre elas. Amostras tratadas com a solução mais concentrada perderam sólidos enquanto que as amostras tratadas com a menos concentrada, perderam água. Na análise de textura, a introdução da trealose não influenciou a força máxima de pico nas amostras impregnadas. Após descongelamento, todas as amostras, exceto a tradada com solução de 500 g/L, sofreram amolecimento. A parte externa dos morangos não sofreu alterações de cor devido à introdução da trealose nem devido ao congelamento e descongelamento. Na parte interna dos frutos, ocorreram variações no parâmetro L* devido à impregnação e no parâmetro b*, devido ao congelamento e descongelamento. / Although freezing offers advantages to others food conservations process, it causes sensorial changes, mostly in vegetables products. The strawberry, a quite appreciated fruit, shows different ways of use, has seasonal behavior and is limited to freezing due the sensorial changes caused by its fragile structure to freezing process. These sensorial changes can be minimized by the incorporation of cryoprotectors, as trehalose, that is known by its cryoprotector effect during freezing and dehydration. The aim of this work was to verify the trehalose cryoprotector effect in frozen and thawed strawberries introduced by vacuum impregnation with different solutions (100, 300 and 500 g/L). The impregnation conditions were 5 min of applying pressure of -650 mmHg and after atmospheric pressure was restored, the sample was maintained within the solution for 10 min (these conditions were obtained from previous experiments). The alterations caused by the vacuum impregnation and the verification of the cryoprotector effect of trehalose were identified by High Performance Liquid Chromatography (HPLC), color analysis, texture analysis, soluble solids content, moisture content and drip loss. The results have shown that concentration of the trehalose solution had a significant influence on the moisture content, soluble solids and trehalose content of impregnated strawberries. The samples treated with more concentration solutions did not dehydrated after thawing. The trehalose content was the same in all treated samples after thawing. All the samples showed the same drip loss due to thawing although the composition of the mass was different among the samples. Samples treated with the most concentration solution lost trehalose while the sample treated with the least concentration solutions lost water. The introduction of trehalose did not affect the maximum peak force of the impregnated samples. The freezing and the thawing process caused the softening of the samples. This effect was not observed on the sample treated with solution of 500 g/L. The introduction of trehalose did not cause significant differences in all color parameters measured on the outside of the strawberries after impregnation and thawing. In the inside of the samples, there were variation in the L* parameter caused by the vacuum impregnations and in the b* parameter caused by the freezing and thawing process.

Strawberry powdery mildew, caused by Podosphaera aphanis, has the potential to cause over 20% yield loss, particularly where strawberries are grown under cover. A holistic approach to the control of strawberry powdery mildew (P. aphanis) is important, since the disease is never absent from the crop. The new disease assessment key was developed to assess strawberry powdery mildew (the old one is for assessing red blotches on leaves, See appendix 8). The results (Chapter 3) showed that the disease is present in the crop when new plants are bought in from a propagator, with 14% of strawberry crowns were infected by P. aphanis in July 2013 and 4% of the strawberry plants had symptoms of powdery mildew in pre-assessment of plants for the 2013 Si nutrient fertigation field experiment. Control measures used in one growing season reduced the disease carry-over, thus reducing the initial inoculum in the following season. The use of a late autumn fungicide spray and a fungicide spray before the plants were covered by fleece in spring reduced the number and maturity of overwintering chasmothecia, thus contributing to a reduction in initial inoculum. The use of silicon (Si) nutrient (foliar spray and root treatment) also suppressed strawberry powdery mildew development (Chapter 4). The results of Area Under Disease Progress Curve (AUDPC) and the rate of epidemic growth curve (r) in 2012 indicated that the high concentration of Si nutrient foliar spray inhibited (r = 0.002, AUDPC = 44) the epidemic build-up of P. aphanis better than the low concentration of Si nutrient (r = 0.012, AUDPC = 51) and untreated (r = 0.018, AUDPC = 70). The Si nutrient root treatment (AUDPC = 12.8) was better in inhibiting strawberry powdery mildew development than the Si nutrient foliar spray treatment. Moreover, the high concentration of Si nutrient foliar spray resulted in fewer chasmothecia compared to the untreated. Si nutrient foliar spray and root treatments increased the concentration of Si in the plants and produced physiological changes in the plants, including wax formation on the adaxial leaf surface, greater leaf thickness and cuticle layer and increased Brix0 value in plants, which all were associated with reduced disease incidence. The integrated use of all these control strategies suppresses disease development so that control is achieved with less use of conventional fungicides.

Orientador: Edson Eiji Matsura / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agricola / Made available in DSpace on 2018-07-31T17:22:05Z (GMT). No. of bitstreams: 1 Passerotti_FernandaReiko_M.pdf: 1738775 bytes, checksum: 4f6eacaeda5cea42ebca7f32a2e55bf8 (MD5) Previous issue date: 2000 / Resumo: Estudos anteriores comprovaram que a aplicação da água pelo sistema de irrigação subterrânea é vantajosa para o desenvolvimento das culturas, pois reduz a perda de água por evaporação, melhorando a eficiência de irrigação e diminuindo o aparecimento de doenças, além de economizar água. Em princípio, o sistema deve produzir uma iãixa larga e contínua de umidade, oferecendo uniformidade de aplicação em todo o seu comprimento. Preocupou-se o uso da irrigação subterrânea em condições de campo, controlando a quantidade de água a ser aplicada, avaliando a uniformidade de aplicação na linha de irrigação em função da textura do solo, a probabilidade de entupimento do equipamento e a comprovação da eficiência do equipamento no fornecimento de água. O tubo de irrigação foi testado a duas profundidades e com aplicação em duas e em três linhas de irrigação por canteiro. Procurou-se avaliar qual o tratamento que oferece melhores resultados para parâmetros de sanidade da planta e de desenvolvimento vegetativo e de sistema radicular. Nas medidas de umidade os tratamentos enterrados a 10 em tiveram resultados mais homogêneos, Não foram observadas diferenças significativas entre os tratamentos estudados para matéria seca da parte aérea (MSP A), índice de área foliar (IAF), máxima dimensão horizontal da pJanta (DHP) e altura da planta (AP), tanto em plantas sadias como em plantas doentes. Na avaliação do sistema radicular, apenas alguns tratamentos apresentaram diferença significativa: os tratamentos de raízes sadias e doentes de O a 10 em e de raízes sadias de SO a 60 cm. Na profundidade de O a 10 em, em plantas sadias, no tratamento com 3 linhas a 20 cm, foram observadas medidas menores que os outros três tratamentos. Já as raizes das plantas doentes, de O a 10 cm de profundidade, mostraram valores de peso seco de raiz maiores nos tratamentos de 3 linhas do que nos tratamentos de 2 linhas de irrigação. De SO a 60 cm, as raízes sadias, tiveram resuhados maiores nos tratamentos de 2 linhas do que nos tratamentos de 3 linhas / Abstract: Previous papers have confirmed that applying water througb the subsurface irrigation system is advantageous for the development of cultures, as it reduces the water loss for evaporation, improving irrigation efficacy and diminishing the emergence of diseases. It also promotes water savings. At first, the system should produce a large and continuous humidity string, providing application uniformity in its whole length. We are concemed about the use of subsurfàce irrigation in field conditions, as for controlling the quantity of water to be applied, assessing the application unifonnity on the irrigation string in function of the soil texture, the probability of the equipment clogging, and the confirmation of the equipment efficiency on water supplying. The irrigation pipe was tested at two depths and with application in two and in three irrigation strings per seedbed. The aim was assessing which treatment offers better resu1ts for sanitation parameters of the plant, the vegetative development and the radicular system. As for the humidity measures, the treatments buried at 10 em (3,9 inches) have presented more. It were not observed significant differences among the studied treatments for dry matter of aerial portion, foliar area index, maximum horizontal dimension of the plant and plant height, both in healthy and in sick plants. On the radicular system assessment, only a few treatments have presented significam differences: the treatments of healthy and sick roots at O to 10 cm (3,9 inches) and heahhy roots at 50 to 60 em (19,6 to 23,6 inches). The treatment at O to 10 cm of healthy 3 L 20 cm plants has presented smaller measures than the other three treatments. As for roots of sick plants at O to 10 em of depth, they've shown Jarger results 00 the 3 strings treatment than on the 2 irrigation strings treatments. From 50 to 60 em, the healthy roots have presented larger results on the 2 strings treatments than the 3 strings ones / Mestrado / Agua e Solo / Mestre em Engenharia Agrícola

Strawberry Reservoir, Utah is an 8.000 acre lake at the elevation of 7,550 feet; it has a maximum depth of 52 feet and an average depth of 18 feet. The supply of cutthroat trout eggs used to replenish and distribute this trout throughout the state are taken from two spawning traps located on reservoir tributaries. Because it has not proven economical to raise cutthroat to a larger size than newly hatched fry, it is at this site they are planted. Because of competition, predation, and lack of space the planting back of fry to maintain the fishery and spawning run presents a serious problem. Tributaries are at carrying capacity from being closed to fishing and the reservoir supports a tremendous population of trash fish; mainly the Utah chub, Gila atraria (Girard); yellow perch, Perca flavescens (Mitchell); redside shiner, Richardsonius balteatus (Cope); mountain sucker, Pantosteus delphinus Cope; and dace. Rhinichthys osculus Cope. The rainbow trout, Salmo gairdneri Richardson. and the cutthroat trout dominate the game fish population. It has been the policy of the Utah State Department of Fish and Game to trap and artificially spawn spawn every possible fish, leaving most of the spawning ground unused. This cost, plus the unknown advantage, if any, of artificial over natural reproduction led to the study of the possibilities of natural reproduction for replenishment of the cutthroat trout in the reservoir.

Gibberellins 3, 4 and 7 were isolated from "Shasta" Strawberry (Fragaria X ananassa Duch.) leaves and identified by gas and thin layer chromatography. In young expanding leaves GA3 occurred at 5 times the concentration of either GA4 or GA7. CCC (2-chloroethyl-trimethylammonium chloride), SADH (Succinamic acid-2,2-dimethyl hydrazide), ethephon (2-chloroethylphosphonic acid), and UBI-P293 (2,3-dihydro-5-6-diphenyl-1,4-oxathiin) were applied to established plantings of three June-bearing strawberry (Fragaria X ananassa Ouch.) cultivars: 11 Shasta, 11 "Fresno" and "Tioga." Treatments were applied on alternate days for three weeks following anthesis of the king blossom. Levels of GA3 and GA4 were reduced by all treatments, but GA7 occurred at such low concentrations that treatment effects could not be measured statistically. Three weeks' exposure to short-daylengths (8 hours of light and 16 hours of darkness) resulted in no change in GA3 or GA7, but GA4 concentrations were significantly reduced . Leaf tissue was analyzed t o e valuate treatment effects on chlorophyll content; no significant changes were observed. No secondary flowering as a result of photoperiod , post-harvest defoliation or growth retardant treatments was observed.

Strawberry powdery mildew, caused by Podosphaera aphanis, affects leaves, fruit, and runners of strawberry plants. Infected leaves have reduced photosynthetic capability and infected fruit become unmarketable. Both of these factors translate to economic loss for the grower and therefore merit taking measures to control the disease. One objective of this study was to evaluate the resistance developed in populations of strawberry powdery mildew to chemical control measures. A fungicide assay was developed to evaluate the efficacy of six treatments (penthiopyrad, quinoxyfen, myclobutanil, trifloxystrobin, cyflufenamid, fluopyram + trifloxystrobin) for control of the disease. Nineteen isolates of strawberry powdery mildew were collected from Balico, Salinas, Watsonville, San Luis Obispo, Santa Maria, Ventura, and Oxnard CA and tested through the assay. The number of isolates resistant to each treatment was: penthiopyrad (7), quinoxyfen (6), myclobutanil (7), trifloxystrobin (2), cyflufenamid (1), fluopyram + trifloxystrobin (0). This documents resistance in P. aphanis to multiple chemicals used for its control. Documentation of any resistance is novel in California and novel worldwide with resistance to Fungicide Resistance Action Committee (FRAC) codes 7 and 13. Another objective of this study was to evaluate host plant resistance to strawberry powdery mildew. Twelve cultivars were evaluated in a winter greenhouse trial, sixteen cultivars in a summer greenhouse trial, and the ten cultivars shared in both trials were also evaluated in two fields. The cultivars found to be most susceptible to mildew infection were BG 3.324 and Royal Royce. The cultivars found to be the least susceptible to mildew infection were Fronteras, San Andreas, and Sweet Ann. The cultivars evaluated represent more than 55% of the state’s acreage and the host plant resistance information will be a valuable tool to growers looking to culturally control powdery mildew.

Studies on plant growth-promoting rhizobacteria (PGPR) and fungi (PGPF) as biostimulants have shown significant positive effects on plant health, fruit yield, or pest management. However, very few published studies to date have been specific regarding their effects on strawberries (Fragaria × ananassa), particularly on soilborne disease prevalence in organically grown strawberries. Empirical data on the results of using these products in commercial growing applications under various conditions would be highly valuable, especially for organic growers who have limited synthetic chemical pesticides, herbicides and fertilizers registered for use. The objective of this study is to evaluate the efficacy of biostimulant supplementation on strawberries for improving fruit yield, fruit quality, and plant health in both high-tunnel, open-sided ‘hoophouse’ and field conditions. This study consisted of two research projects. The first project investigated the effects of commercially available PGPR-based biostimulant products on strawberry plant health. The three products contained differing proprietary combinations of PGPR, primarily from the Bacillus and Lactobacillus genera. Plants were grown in two different soil types: sandy and clay, in order to investigate the effects of biostimulant supplementation in different soil conditions. In fall of 2018, 160 ‘Monterey’ strawberry plants were grown in an outdoor hoophouse in 3-gallon pots. Plants were either treated monthly with a single bacterial biostimulant product (EM-1, Accomplish LM, or Armory), or left untreated as a control. Plants were grouped into 20 blocks, each block comprised of 8 plants (each of the four treatments replicated in both soil types). Fruit yield (g), fruit sugar content (Brix), and leaf SPAD absorbance levels were measured weekly from January 27 to June 26, 2019. The treatments tested had no significant effects on fruit yield, leaf SPAD absorbance or Brix; soil type, however, did significantly impact fruit yield, with higher yields in sandy soil. The second project was a field trial beginning in spring of 2020, in collaboration with Rutiz Farms in Arroyo Grande, CA, involving a total of 480 ‘Chandler’ strawberry plants. The farm is organically managed and has a history of soilborne diseases, including Verticillium dahliae. These plants were either treated monthly with one of three microbial biostimulant products: a product containing a proprietary strain of Trichoderma harzianum biocontrol fungus (TrichoSym), and two of the same PGPR-based products used the previous year (Accomplish LM and Armory); or left untreated as a control. The experiment was laid out in a randomized complete block design with four blocks, with each block consisting of 4 plots for each of the 4 treatments; each plot contained 30 plants. Fruit yield (g) per plot was measured weekly throughout the 2020 growing season and phenotypic disease incidence was measured biweekly. Soil samples were taken at three different points throughout the season, cultured on selective media, and analyzed to obtain estimates of V. dahliae colony-forming units (CFU) per gram soil. The treatments tested had no significant effect on fruit yield, phenotypic disease incidence, or V. dahliae CFU/g soil. The results are inconclusive as to whether this lack of effect is due to viability of the products themselves, ineffective application techniques resulting in lack of rhizosphere colonization, or some combination of these. Further research is needed to determine whether or not supplementation with microbial biostimulants can produce reliable, beneficial results in strawberries.

Gray mold of strawberry, caused by Botrytis cinerea, is a very destructive pre- and post-harvest fruit rot. Outside of California, fungicide resistance in B. cinerea has been reported to every site-specific chemical class labeled for use against gray mold. One objective of this study was to characterize the resistance of 888 isolates of B. cinerea from California strawberry fields to ten active ingredients. Isolates were collected from the same planting block in 47 fields during the early-season (0 to 8 fungicide applications) and late-season (16 to 26 fungicide applications) of 2016. Sensitivity of each isolate was determined using the following active ingredients at a discriminatory dosage (μg/ml): boscalid (75), cyprodinil (4), fenhexamid (50), fludioxonil (0.5), fluopyram (10), iprodione (10), isofetamid (5), penthiopyrad (5), pyraclostrobin (10), and thiophanate-methyl (100). Resistance to each active ingredient was observed at varied frequencies (early-season %, late-season %): boscalid (12, 35), cyprodinil (12, 46), fenhexamid (53, 91), fludioxonil (1, 4), fluopyram (2, 7), iprodione (25, 8), isofetamid (0, 1), penthiopyrad (8, 25), pyraclostrobin (77, 98), and thiophanate-methyl (81, 96). Captan, boscalid, cyprodinil, fenhexamid, and fludioxonil were the most commonly used fungicides in surveyed strawberry fields. A selection of 100 isolates was identified to the species level. All isolates were B. cinerea, excluding one isolate of Botrytis mali. A fungicide resistance trial was conducted v to observe resistance responses in populations of B. cinerea. Frequencies of resistance to boscalid and fludioxonil remained unchanged despite consecutive applications of these fungicides. Frequency of resistance to fenhexamid increased when this fungicide was applied and decreased when it was not. This occurred in fungicide treatments including fungicide rotation, tank-mixing with captan, and consecutive applications of fenhexamid. Multi-fungicide resistance was widespread in California strawberries; isolates resistant to fenhexamid, thiophanate-methyl and pyraclostrobin were the most common phenotype. The frequency of resistance increased from the early-season to late-season for multiple active ingredients tested. This within-season change in frequency of resistance was tested and confirmed in a field trial, where common resistance management strategies failed to prevent the buildup of fenhexamid resistance. New and improved methods of resistance management may need to be enacted to ensure the future efficacy of site-specific fungicides.

No description available.