• Research in Plant Disease
• /
• v.28 no.2
• /
• pp.61-68
• /
• 2022

Powdery mildew and two-spotted spider mite are detrimental to strawberry plants and are controlled with traditional pesticides. To accommodate consumer demand, eco-friendly methods of pest control are required. Strawberries were cultivated (in soil and in a hydroponic system) for two years, and ultraviolet B (UV-B) irradiation was used as an alternative pest control during the harvesting season. Three varieties were grown (Seolhyang, Kingsberry, and Durihyang), and four UV-B lamp/mulch (black, green, and light reflection sheet [LRS]) combinations were used during harvesting: UV-B+black or green mulch, UV-B+black or green+LRS, no UV-B+black or green, and no UV-B+black or green+LRS. In all varieties, powdery mildew was 65% more controlled when UV-B irradiation was used. The adult two-spotted spider mite density was lowest in the UV-B lamp+black or green+LRS treatments. Therefore, UV-B irradiation during the strawberry harvesting season could effectively control powdery mildew and two-spotted spider mite with little side effect on the plants.

• Korean Journal of Environmental Agriculture
• /
• v.41 no.4
• /
• pp.282-287
• /
• 2022

BACKGROUND: Green algae (Chlorella spp.) has been widely used as a biofertilizer to improve the crop yield and quality. However, available information is not enough to verify the mechanism of green algae's beneficial impact on strawberry. This study was conducted to investigate the effect of Chlorella fusca CHK005 application on the growth and nutrient status of strawberry plant and fruit characteristics. METHODS AND RESULTS: A total of 800 seedlings of strawberry variety 'Kuemsil' were planted. Once a week, C. fusca culture solution (1.0 × 10⁷ cells mL^-1) was applied into soil via irrigation in four different concentrations: no application (control), 1/1000 times (× 0.5), 1/500 times (× 1), and 1/250 times (× 2). Result showed that growth of strawberry plant was enhanced by Chlorella application and the highest impact on fresh weight (FW) and chlorophyll content of the plants were observed in × 2 treatment, followed by × 1, × 0.5, and control treatments. The phosphorus (P) concentration in the plant was significantly higher in × 1 and × 2 treatments compared to control. In case of fruit quality, sugar content (°Brix), hardness, and FW were lowest in control, but these values increased as application levels of Chlorella were higher. Also, P and K contents in the fruits increased with increasing the application levels and significant correlation between P content and oBrix in the fruits was found. CONCLUSION(S): Overall, Chlorella application seemed to improve plant growth and fruit quality by increasing the utilization efficiency of P and K in strawberries.

• Korean journal of applied entomology
• /
• v.52 no.4
• /
• pp.357-364
• /
• 2013

Bee-vectoring is a new crop protection technology used for suppressing insect pests and diseases in crops by disseminating microbial agents into plants during bee pollination activities. In this study, we conducted bee-vectoring trials in cherry tomato greenhouses by using the bumble bee (Bombus terrestris), a microbial agent (Bacillus subtilis) and a new dispenser, and we measured the delivered quantity of microbial agent. Bacterial colony forming units (CFUs) in bees exiting a dispenser ranged from $9.0{\times}10^5$ to $1.9{\times}10^6$ per bee. At greenhouse trials in the National Academy of Agricultural Science (NAAS) trials, 3,300 - 8,500 CFUs per flower were counted and 80 - 100% of the flower samples contained detectable concentrations. There was no significant difference in CFU density between microbial replacement intervals (once a week vs twice a week) in the NAAS trials. In a commercial greenhouse trial, 1,800 - 2,400 CFUs per flower were found, and 83 - 93% of the flower samples contained detectable concentrations. CFUs detected in bee-vectored flowers increased by approximately 75 times before bee-vectoring. The mortality of bumble bees in the NAAS trials was, on average, 22% and little negative effects were observed on the bumble bee colonies. The yield difference for cherry tomatoes in the NAAS trials was not significant between treatments. When we select additional microbial agents that can be disseminated using this technology and create a detailed plan based on insect pests and disease incidence, we can apply this technology in greenhouses for growing tomatoes and strawberries in the near future.

• Horticultural Science & Technology
• /
• v.31 no.3
• /
• pp.282-288
• /
• 2013

This study was conducted to investigate the quality characteristics of eight everbearing strawberry cultivars and the effect of precooling treatment to maintain the quality during storage and shelf life of 'Charlotte'. Several quality parameters including firmness, soluble solids content (SSC), color, soluble sugars, and organic acids were evaluated. For Successful marketing everbearing strawberries required more than 1 N of firmness and $6^{\circ}Brix$ of SSC, respectively. 'Albion', 'Charlotte', and 'Goha' cultivars were higher in fruit SSC and 'Charlotte' cultivar was higher in fruit firmness among eight cultivars examined in this study. Fruit had more bright red color in 'Charlotte', 'Flamingo', 'GW-4', and 'San Andreas', which may reflect the consumer acceptance. Physicochemical characteristics of 'Charlotte' strawberry after with/without room precooling treatment were evaluated during storage at $4^{\circ}C$, $10^{\circ}C$, and $25^{\circ}C$ and additional 3 days at $25^{\circ}C$ for shelf-life. Weight loss increased about 8% in the fruits stored at $25^{\circ}C$ for 3 days, while in low temperature storage was about 2% for 7 days showing precooling was more effect on during shelf life periods rather than storage periods. Decay was not found during storage at $4^{\circ}C$ regardless of precooling treatment, but fungal growth was found in all the treatments after transferred to room temperature. Precooling treatment did not affect fruit color in shelf life period. For advanced marketing, everbearing strawberry should maintain in low temperature less than $4^{\circ}C$ to sustain quality, but the room precooling showed less significant effect to maintain quality on 'Charlotte' cultivar.

• Korean journal of food and cookery science
• /
• v.23 no.4 s.100
• /
• pp.423-432
• /
• 2007

The purpose of this study was to investigate the seasonal variations in water, protein, lipid, ascorbic acid, and ${\beta}-carotene$ contents of 17 vegetables and 4 fruits that are available all the year round and frequently consumed by Koreans. The water contents of the fruits ranged from 83-89%, and the vegetables contained more water than the fruits. The apples and pears had more water in the spring and summer than in the fall and winter. The tangerines showed a high water content in the winter, whereas the strawberries contained more water in the fall. The vegetables also showed seasonal variations in water content. The protein contents of the fruits were lower than 1%; the cucumbers contained 0.1% protein, which was the lowest level, but spinach, lettuce, bean sprouts, sesame leaves, and mushrooms had more than 1% protein. The ascorbic acid and ${\beta}-carotene$ contents of the apples, pears, and tangerines were higher in the fall and winter than in the spring and summer. The vegetables, in general, contained more ascorbic acid than the fruits. The cabbage and radishes showed higher ascorbic acid contents in the fall and winter than in the spring and summer, indicating that vegetables as well as fruits are more nutritious during their harvest season. The zucchini, spinaches, and green peppers had higher ${\beta}-carotene$ contents in the winter than in the other seasons. The above results show that there were seasonal differences in the ascorbic acid and ${\beta}-carotene$ contents of the fruits and vegetables. In addition, the fruits and vegetables had a tendency to contain more ascorbic acid and ${\beta}-carotene$ in the season they were harvested. Therefore, we recommend the consumption of those fruits and vegetables during their harvest season.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.42 no.2
• /
• pp.212-222
• /
• 2013

We studied the eating habits and sleeping patterns of 682 middle and high school students in their third year in Gwangju. According to the body mass index (BMI) of the subjects, obesity (over weight) was significantly higher in the third graders of high school students ($20.8{\pm}4.0$, 32.9%) than middle school students ($19.4{\pm}3.8$, 14.2%) (p<0.001). In addition, 71.1% of high school students experienced a lack of sleep compared to 48.8% of middle school students (p<0.001). There was a difference between good and bad sleepers in the number of times they ate snacks and the quantity of their snacks. Good sleepers had more fruit and dairy products (e.g. fruit juice 2~4 times (p<0.05), milk 2~4 times (p<0.001), apples 2~4 times, strawberries 2~4 times (p<0.01), and bananas 2~4 times a week), while bad sleepers consumed more beverages, frozen desserts, flour-based foods, fast food, bread, and rice cake. Bad sleepers clearly consumed snacks more frequently. From analyzing the correlations between sleep quality and snack intake, eating fruits 2~4 times a week (30 g~200 g/once) and drinking dairy products 2~4 times a week (120 mL~400 mL/once) appears to promote better sleeping habits.

• Horticultural Science & Technology
• /
• v.31 no.2
• /
• pp.173-178
• /
• 2013

Experiments were conducted to investigate the optimum concentration of nutrient solution for strawberry 'Maehyang' bred domestically for exportation in hydroponics. Nutrient solutions for strawberry, which was made by Yamazaki, were supplied electrical conductivity (EC) 0.6, 0.8, 1.2, and $1.8dS{\cdot}m^{-1}$ after planting on cocopeat medium during the experiment period. Growth of shoot of strawberries did not show any statistical differences among treatments. Fruit length showed the longest in EC 0.8 and $1.2dS{\cdot}m^{-1}$, followed by 0.6 and $1.8dS{\cdot}m^{-1}$ in the first and third cluster. It showed the shortest in EC $1.8dS{\cdot}m^{-1}$ in the second cluster but there were no significant differences among treatments in the fourth cluster. Fruit diameter did not show significant differences among treatments in the first and second cluster but was the longest in the lowest concentration EC $0.6dS{\cdot}m^{-1}$ in the third cluster. The shortest was in EC $1.8dS{\cdot}m^{-1}$ in the fourth cluster. The heaviest mean fruit weight appeared in EC 0.8 and $1.2dS{\cdot}m^{-1}$, and the lightest was in EC $1.8dS{\cdot}m^{-1}$ in the first cluster and also lightest in EC $1.8dS{\cdot}m^{-1}$ but no significant differences was found among other treatments in the second & third cluster. Also the fruit weight was significantly light in plants grown in EC $1.8dS{\cdot}m^{-1}$ than $0.6dS{\cdot}m^{-1}$ in the fourth cluster. Soluble solids content of fruit was the highest in EC $0.6dS{\cdot}m^{-1}$ in all cluster. As a result, we came to the conclusion that the optimum EC for strawberry 'Maehyang' was EC 0.8 - $1.2dS{\cdot}m^{-1}$ during low temperature season. This result will be utilized as an indicator for strawberry hydroponics.

• Journal of Bio-Environment Control
• /
• v.26 no.3
• /
• pp.227-234
• /
• 2017

This study aimed to investigate the nutrient solution developed by based on nutrient-water absorption rate of strawberry 'Maehyang' by comparing growth and yield for 8 months with 5 kinds of nutrient solution with different ion composition. Strawberry plants were planted at elevated bed and supplied with five kinds of nutrient solutions (RDA), Yamazaki, PBG, University of Seoul (UOS) and NewUOS from one month onwards. Five types of nutrient solution were supplied to the strawberry plants associated with EC $1.0dS{\cdot}m^{-1}$, pH 6.0, $150{\sim}300mL{\cdot}plant^{-1}$ per day. At 60 days after planting, leaf width and leaf petiole of the strawberry plants showed significant differences among nutrient solution types and photosynthesis was higher in RDA and NewUOS nutrient solution and lower in PBG nutrient solution. The EC of the drainage on vegetative growth stage was $0.7{\sim}0.8dS{\cdot}m^{-1}$, which is lower than the supplied EC level, and to $1.0-1.2dS{\cdot}m^{-1}$, afterwards. The pH of the drainage was higher in Yamzaki solution as 6.2~6.8, while the pH of the UOS nutrient solution was lower in 5.1~5.2. Nitrate content was most absorbed in vegetative growth stage and after flower clusters development. The potassium uptake was highest at the NewUOS followed by UOS and Yamazaki nutrient solution. At six months after -planting fresh weight and dry weight of shoot and root were higher in UOS and NewUOS nutrient solution than other nutrient solutions, and the dry matter ratio was lower at 43.5% in Yamazaki nutrient solution and 30.6% in NewUOS nutrient solution than other solutions. Length, width, weight, and sugar content of the strawberries harvested from December to February were unaffected by treatment, but yield was higher in NewUOS nutrient solution due to increasing fruit number and average weight. From March to May, number of fruit was higher in Yamazaki nutrient solution. In conclusion, there was no difference in the growth of 'Maehyang' when 5 nutrient solutions were grown under hydroponics. But in order to improve the marketability, the NewUOS nutrient solution is appropriate to use from planting to February and it is suitable to use Yamazaki nutrient solution after March when temperature is high and the amount of fruit set per inflorescence.

• Horticultural Science & Technology
• /
• v.31 no.1
• /
• pp.56-64
• /
• 2013

Recent unusual weather due to global warming causes shortage of daily sunlight and constitutes one of the primary reasons for agricultural damages. LED light sources are frequently utilized to compensate for the shortage of sunlight in greenhouse agriculture. The present study is aimed at evaluating formations of phytochemicals as well as growth characteristics of mature strawberry fruits ('Daewang' cultivar) during cultivation in a closed growth chamber equipped with artificial LED light as a sole light source. Each LED light of blue (448 nm), red (634 and 661 nm) or mixed blue plus red (blue:red = 3:7) was separately supplied and the intensity of each light was adjusted to $200{\pm}1{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ at plant level with a photoperiod consisted of 16 hours light and 8 hours darkness. Strawberries grown under mixed LED light of blue and red wavelengths showed a higher production of fruits than those grown under other LED treatments. Fructose, one of the free sugars, increased in mixed LED light-grown fruits. Anthocyanin contents were elevated remarkably in the mixed LED light-grown fruits compared with those in other LED treatments. Contrastingly, contents of total phenolics and flavonoids were not of much different from one another among the fruits treated with various LED lights. On the other hand, ripening of strawberry fruits was found to be faster when grown under blue LED light compared with other LED treatments. Moreover, antioxidant activities of blue or red LED light-grown fruits, respectively, were significantly higher than those of mixed LED light-grown fruits. We suggest that when daylight is in shortage during cultivation in a greenhouse, supplementation of sunlight with LED light, which is composed of blue and red wavelengths, could be useful for the enhancement of productivity as well as of free sugar content in strawberry fruits. In addition, for the strawberry culture in the plant factory, selective adoption of LED light wavelength would be required to accomplish the purpose of controlling fruit maturation time as well as of enhancing contents of sugars and antioxidants of fruits.

• Korean journal of food and cookery science
• /
• v.19 no.2
• /
• pp.165-173
• /
• 2003

This study was carried out to develop a better fruit-dressing than previous mayonnaise in terms of calories, salt content and color, using kiwis, oranges, strawberries, and apples. This study was aimed to identify the perception, physico-chemical and sensory characteristics of the 4-kinds of fruits dressing. The results were as follows: The perception of the fruit dressings received the highest score (3.90) for 'It's convenience foods'. The misture in the dressings ranged from 49.3 to 59.4%, and was highest in apple dressing, followed by the kiwi, strawberry, and orange dressings, in that order. The crude ash for the dressings ranged from 0.8 to 1.4%, and was highest in the orange dressing. The L value was highest in the apple dressing, the a(-) value in the kiwi dressing, the a(＋) value in the strawberry dressing and the b value in the orange dressing. The Ca/ P ratio was about 1.17 : 1. The results of mineral contents analyses were also examined. The calcium, magnesium and potassium levels were highest in the orange dressing. The mineral contents of fruit dressings were 6.7 to 20.4mg/100g for calcium, 6.5 to 20.5mg/100g for magnesium and 67.2 to 182.6mg/100g for potassium. The sodium content of the fruit dressings were lower than in the previous mayonnaise, especially for the kiwi-dressing, which was 30% that in the mayonnaise. As a result of the sensory evaluations of the 4-kinds of fruits dressing, the kiwi dressing received the highest scores (3.50) of all the fruit-dressings in relation to the taste and palatability. Fruit are good for producing dressings that are low in calories and salt, with kiwi dressing proving to be the best of those fruits tested.