Managing Strawberry Pests with Chemical Pesticides and Non-Chemical Alternatives

ABSTRACT

Western tarnished bug or lygus bug (Lygus hesperus) is a major pest of California strawberries causing significant yield reduction. Other common insect pests include aphids (Chaetosiphon fragaefolii and Myzus persicae), greenhouse whitefly (Trialeurodes vaporariorum), and western flower thrips (Frankliniella occidentalis). Growers mainly depend on chemical pesticides for managing these pests. Limited control with some of the available chemical pesticides and the risk of resistance development due to their repeated use warrant a strong integrated pest management program where multiple tools can be utilized. Field studies conducted in commercial strawberry fields from 2012–14 in Santa Maria with an emphasis on managing L. hesperus demonstrated the potential of botanical and microbial pesticides. Replacing one or more applications of chemical pesticides with botanical and microbial alternatives and using them in different combinations can make a significant contribution to a sustainable management strategy.     

Initial Crown Diameter of Transplants Influences Marketable Yield Components of Two Strawberry Cultivars in Annual Hill Production System

Abstract

Influence of initial transplant size on yield components was investigated using two strawberry cultivars over a three-year period. Plants were sorted into three groups according to crown size each fall before transplanting.

Fruits were harvested once a week over a ten-week period each year. There were marked differences between ‘Chandler’ and ‘Camarosa’ cultivars. Transplants of the ‘Chandler’ cultivar with larger crown diameters produced significantly greater early and total marketable yield than transplants with smaller crown diameters. Regression analysis of yield components against initial crown diameter revealed a positive relationship between total fruit numbers produced per plant and initial crown size for both cultivars. Total weight of marketable fruit produced per plant was positively associated with initial crown diameter of transplants. Relationships between initial crown diameter and early yield components were not as consistent among the two cultivars tested. Early yield components of ‘Chandler’ were all correlated to initial crown diameter of transplants. The size of the transplant did not influence early yield components of ‘Camarosa’ except for fruit size. There was a significant relationship between the postharvest dry weight of plants and initial crown diameter of transplants.     

Non-Fumigant Treatments and Their Combinations Affect Soil Pathogens and Strawberry Performance in Southern California

ABSTRACT

Finding effective non-fumigant solutions to soil disinfestation is an international priority for sustainable strawberry production. In these studies at Ventura, California, combinations of steam, solarization, and mustard meal were evaluated to manage troublesome soil-borne pathogens: Macrophomia phaseolina and Fusarium oxysporum. Treatments containing steam and solarization reduced levels of these pathogens in soil 70–96% compared to untreated soil and had lower rates of late season pathogen-related plant mortality. All treatments improved plant canopy growth and fruit production of ‘San Andreas’ strawberry 58% to 83% compared to untreated control. Even though these treatments did not eradicate pathogen spores and sclerotia in soil, they enhanced early and whole season fruit production and when feasible can be applied in non-fumigated and organic strawberry fields to help sustain production.     

Fruit Quality and Composition of Two Advanced North Carolina Strawberry Selections

ABSTRACT

The advanced selections, NCS 10-038 and NCS 10-156, from the North Carolina breeding program were compared to the traditionally used cultivars, Camarosa and Chandler, for storage life and fruit composition in 2014 and 2015. Postharvest quality of NCS 10-038 was similar to that of ‘Camarosa’ and ‘Chandler’ after 8 days storage at 4 °C. NCS 10-156 was significantly worse in overall appearance and had more fruit shrivel, calyx browning, and mold than the other genotypes. However, NCS 10-156 was highest in soluble solids content and was similar in total anthocyanin content and total phenolic content to ‘Camarosa’ and ‘Chandler’. Further analysis of flavonoids by high performance liquid chromatography showed that NCS 10-156 was much lower in total flavonols than the other genotypes and comparable in anthocyanin pigments to ‘Chandler’. NCS 10-038, while similar in pigment profile to ‘Camarosa’, had less total anthocyanin than the other genotypes. NCS 10-038 had a lighter red color than the other genotypes and was similar in postharvest quality to ‘Chandler’ and ‘Camarosa’ and may be suitable for long-distance markets. NCS 10-156 is slightly softer than the other genotypes and more prone to mold while the higher soluble solids content may make it suitable for direct market sales. Both selections show postharvest promise for strawberry production in the humid mid-South region.     

Effect of Planting and Harvesting Dates on Strawberry Fruit Quality under High Tunnels

ABSTRACT

There is an increasing demand in the market to improve strawberry quality by promoting human-health compounds content, as these may play a significant role in the prevention of chronic diseases. Strawberry cultivars, environmental conditions, and agronomical conditions have an effect on fruit characteristics; therefore, it is necessary to constantly generate information about the cultivar response to different production areas and cultural practices. The goal of this work was to evaluate the effect of two planting dates, two harvest dates, and four strawberry cultivars on total phenolic acid (gallic acid equivalent), ascorbic acid (vitamin C), and soluble solid content?titratable acidity-1 (SSC?TA-1) ratio in Huelva, Spain. Sixteen treatments resulted from the combination of four cultivars, two planting dates, and two harvest dates. Strawberry ‘Camarosa’, ‘Sabrosa’, ‘Aguedilla’, and ‘Fuentepina’ were selected for both seasons and planted on 7 Oct. (early planting) and 21 Oct. (late planting). Mid-February and mid-April were considered early and late harvest, respectively. Nutraceutical and organoleptic responses were specifics for each cultivar. The highest SSC?TA-1 ratio was observed in ‘Fuentepina’ planted late and harvested early. ‘Aguedilla’ resulted in the highest phenolic content when harvested in the late season. Additionally, phenolic content was significantly higher when using late planting combined with late harvest in most of the cultivars. Late harvested ‘Camarosa’ showed the highest TA concentration, whereas ‘Sabrosa’ resulted in the highest SSC regardless of harvesting date. Additionally, ‘Aguedilla’ and ‘Sabrosa’ showed the highest ascorbic content. Strawberry quality could be improved by selecting the adequate planting and harvesting dates according to specific cultivars.     

不同培养条件对‘丰香’草莓离体叶片再生的影响

 以草莓品种‘丰香’离体叶片为外植体, 探讨了基本培养基、不同细胞分裂素、暗培养、硝酸银浓度以及不同植物生长调节剂组合对不定芽再生的影响。结果表明, 基本培养基中以MS 最为适合,WPM、QL 、AS 培养基均不利于不定芽的再生, 而TDZ 的诱导效果好于BA。以MS 基本培养基附加TDZ2.0 mg·L - 1和IBA 0.8 mg·L ^-1可以使‘丰香’叶片不定芽的再生率高达72.33 % , 平均每叶再生芽5.59个。暗培养14 d 可以将‘丰香’叶片的不定芽再生率提高到90.09 %。硝酸银对于提高‘丰香’叶片的不定芽再生没有明显效果, 但在一定程度上改变了细胞分化的方向。     

Romina and Cristina: Two New Strawberry Cultivars with High Sensorial and Nutritional Values

ABSTRACT

The two cultivars (Romina and Cristina) recently released from the Marche Polytechnic University (Ancona, Italy) strawberry (Fragaria × ananassa) breeding program, show high adaptability to non-fumigated soil. Furthermore, ‘Romina’ showed very early ripening, conic or bi-conic fruit shape, good taste with high sweetness, high firmness and shelf life, and high vitamin C and folate contents. ‘Cristina’ showed very late ripening, high productivity, large fruit of conical shape, good taste, and high vitamin C and folate contents. The European Union patents of ‘Romina’ and ‘Cristina’ have been transferred to the United States, and nursery production has begun following United States rules to determine future market interest.     

Short days and temperature effects on growth and flowering in strawberry (Fragaria × ananassa Duch.)

Summary

‘Korona’, ‘Elsanta’, ‘Bounty’ and ‘Senga Sengana’ strawberry (Fragaria × ananassa Duch.) plants, were placed at constant temperatures of 9, 15 or 21°C and daylengths of 8 h (short day) or 24 h (long day). The plants were given different numbers of short-day (SD) cycles, and flowering and growth were studied. ‘Korona’ and ‘Elsanta’ were responsive to both short-day treatment and temperature, with optimum flowering at 15°C and 24 SD. ‘Bounty’ was more responsive to temperature, inducing flowers independently of the number of SD cycles at 9°C and 15°C. In ‘Senga Sengana’ flowering was induced independently of temperature and the number of SD cycles, indicating that it had a stronger dependence on other environmental effects. The effect of the number of short-day cycles and the temperature on vegetative growth variâtes such as the number of stolons and daughter plants, the length of flower trusses and petiole length were also studied.     

Determination and confirmation of S-RNase genotypes of apple pollinators and cultivars

Summary

We analysed the S-RNase genotypes of 23 crab apple (Malus spp.) pollinators and 102 cultivars of domestic apple (Malus pumila Mill.) by PCR amplification and digestion. Within the 23 pollinators, four pollinators, ‘Hopa’, ‘Jack’, ‘Pink Perfection’ and ‘Profusion B’, each had two unidentified S-RNase alleles. These cultivars should be useful pollinators for all domestic cultivars. Twenty-one of the domestic cultivars exhibited S-genotypes contrary to those expected from their supposed parentage, suggesting that one or both reported parents were wrong. We confirmed many of the S-RNase genotypes by pollination tests.     

Improving Pollination of Early Strawberry Crops

ABSTRACT

Our work on strawberry pollination started in 1996 because die top cultivar grown in France is ‘Gariguette’ and growers get good prices widi this cultivar very early in the season (March-April) as the quality of the product is well recognized. Crop management aimed at earliness (early covering, covering with a layer of non-woven fabric or under greenhouse polyethylene film, heating, etc.) induces the plant to flower under conditions unfavorable for pollination such as short days with low irradiation levels and temperatures around 8-10°C which hinder pollen formation. Such conditions often lead later on to problems in strawberry development and shape (large areas with unfertilized ovules, furrows, etc.). This is especially true for primary flowers, which should provide the largest strawberries. A preliminary study was first conducted to assess whether pollination was, indeed, a limiting factor for strawberry production in early crops and whether female reproductive structures also have played a role as well. When this work was completed and pollination was demonstrated as the main limiting factor for strawberry development from the first batch of flowers, the authors studied the different pollen vectors and quantified their action to determine their incidence in terms of production under “limiting” early cropping conditions.     

Strawberry Production,Growth and Development in Northern Climates

Abstract

This paper focuses on the cropping systems in northern European countries such as Norway and Finland. Winter injury commonly occurs in strawberry fields in northern climates and inadequate snow cover further aggravates the problem. During the last decade there has been an increase in programmed “out-of-season” strawberry production. Greenhouse producers aim for year-round production, whereas those using polyethylene tunnels extend the main production season to include May/June and September/October. The dominant strawberry cultivars in Nordic countries are ‘Senga Sengana’ for the processing industry and the Dutch cultivar ‘Korona’ is preferred for direct fresh market consumption due to its good flavor and high yields. Recently, ‘Honeoye’ has gained considerable interest among Danish and Swedish growers due to its high productivity and its relatively low susceptibility to grey mold. In Finland, the Norwegian cultivar ‘Jonsok’ is one of the most popular cultivars due to its high tolerance to winter injury and grey mold.     

草莓新品种‘晶瑶’

 ‘晶瑶’是以‘幸香’为母本, ‘章姬’为父本杂交育成的早熟草莓新品种, 其休眠期短, 果实呈略长圆锥形, 表面鲜红色; 果实整齐, 一级序果平均29.6 g; 肉质细腻, 香味浓, 口感好, 耐贮运;抗白粉病能力强。平均产量为330 g·株^-1 , 32 475 kg·hm ^-2。     

The Incorporation of Growth Hormones in Seed Dressings

Summary

The consequences of using ex vitro, single-node explants from different topophysical positions in chrysanthemum (Chrysanthemum grandiflorum /Ramat./ Kitam) were determined. In particular, how explant topophysis affected the rate of propagation, which is important for the successful micropropagation of chrysanthemum. Uniform shoots of five cultivars of chrysanthemum, cultured in vitro, were each divided into three equal zones: distal, central, and proximal. Two single-node explants were isolated from each zone and cultured on MS medium without any added growth regulators. After 10 weeks of culture, 50% of the shoots that had developed from axillary buds on each single-node explant were excised and measurements were taken in order to compare those shoots that had developed from explants from the different topophysical zones. The remaining shoots were sub-cultured on rooting medium. After 4 weeks, the numbers of roots per plantlet, and the total fresh weight (FW) of roots were recorded. The cultivars fell into two groups. ‘Lady Amber’, ‘Lady Orange’, and ‘Lady Vitroflora’ explants were topophysis-dependent, while ‘Lady Bronze’ and ‘Lady Rosy’ explants were topophysis-independent. For the three topophysis-dependent cultivars, the propagation rate, growth rate, shoot length, internode length, single leaf weight, and total plantlet FW values were highest for those shoots derived from the central and proximal zones. Topophysis failed to affect the number of leaves per shoot or the number of days between the appearance of two successive leaves. The effects of topophysis on the number of roots per plantlet and on root FW were inconsistent. The unequal growth of chrysanthemum plantlets during in vitro micropropagation can be an effect of topophysis, and this phenomenon is cultivar-specific in chrysanthemum.     

The influence of transplant age and nutrient feeding regime on cauliflower growth and maturity

Summary

Similar experiments in 1984 and 1985 examined the effects of cauliflower transplant age and ‘high’ or ‘low’ nutrient feeding regimes during plant.raising on the numbers of leaves formed, the timing of curd initiation, maturity and other maturity characters. ‘High’ nutrient feed contained 104 mgl^?1N and 290 mgl^?1K whereas ‘low’ nutrient feed contained 52 mg l^?1 N and 145 mg l^?1 K. In addition, in 1985 the growth of other ‘low-feed’ plants was boosted by giving them ‘high feed’ during the last four days before transplanting. The raising treatments produced transplants which differed in dry weight, in the numbers of leaves formed and especially in dry-matter percentage. In both years the oldest ‘low-feed’ plants had the highest dry-matter percentage at transplanting (mean 22.2%) whereas the youngest ‘high-feed’ plants had the lowest dry-matter percentage (mean 12.9%). After transplanting, differences between treatments rapidly disappeared and there were few significant effects of treatments on the time of curd initiation, the final number of leaves formed, the time of 50% curd maturity and marketable curd yield. It is concluded that when planning cauliflower continuity schedules the time of transplanting is important but the precise age of plants at transplanting and the feeding regime prior to this need not be taken into account provided plant size is kept within normal limits.     

The effect of salt stress on lime aphid abundance on Crimean linden (Tilia ‘Euchlora’) leaves

Many authors claim that trees planted along streets are weaker because of environmental pollution, especially high soil salinity, which results in greater susceptibility to attacks by pathogens. The Tilia ‘Euchlora’ (Crimean linden) is described as one of the urban greenery species that is most prone to the effects of salinity. The aim of this research was to assess the influence of salt stress on the lime aphid abundance on the leaves of Tilia ‘Euchlora’. The average number of aphids was lower for trees growing along the street and subjected to de-icing salt than in the controlled park area. It was strongly negatively correlated with the Na and Cl level in the leaves, whereas it was positively correlated with the content of N and P. The study showed that the aphids’ abundance was most strongly influenced by the N and Cl content in the leaves (although in opposite ways). When the amount of nitrogen increased by 1.0% (from 2.0 to 3.0%), the abundance of aphids increased by 116%. An increase by 1.0% (from 1.0 to 2.0%) in the Cl content in the leaves resulted in a decrease in the abundance of aphids by 36%. The toxic Cl level (over 1%) was exceeded only in the leaves of trees growing along a busy street (79% of the examined individuals in this location), whereas it ranged from 0.23% to 0.40% for the trees from the park. There was concluded that aphids probably prefer trees with healthier leaves for their feeding, i.e. leaves of lower amount of Cl and Na, while with higher concentration of N.     

草莓叶面施硒对其重金属镉和铅积累的影响

 以‘北农3号’草莓为试材,以清水喷施为对照,用0.5、1.0、2.5、5.0、10.0 mg · L^-1浓度的亚硒酸钠进行叶面喷施,定期采样进行硒、镉和铅和相关生理指标的动态监测,研究叶面施硒后重金属镉和铅在草莓机体内的积累情况和草莓生理代谢机制的变化,探明硒对镉和铅的互作效应。结果表明,草莓在展叶期和盛花期对硒的吸收能力最强,且施用2.5 ~ 5.0 mg · L^-1适宜浓度硒后,硒可通过清除膜脂过氧化产物丙二醛（MDA）,保护细胞膜的完整性,降低重金属离子的含量,有效抑制草莓叶片和果实对重金属镉和铅的吸收,证明叶面施硒不仅是草莓补硒的较好手段,而且适宜浓度的硒可减少草莓对重金属镉和铅的吸收。     

Strawberry Growth and Development in the Mild Winter European Regions

Abstract

In the mild winter regions strawberries are the most important crop of the small fruits. Strawberry production systems rely on the ‘winter’ planting system developed in California for early production and predominantly on California cultivars with plants set at high densities. The aim of this paper is to provide a brief review of strawberry growth and development in the mild winter regions based on a review of the literature and on research studies carried out in southwestern Portugal.     

The Effect of a Substrate Containing Arbuscular Mycorrhizal Fungi and Rhizosphere Microorganisms (Trichoderma,Bacillus, Pseudomonas and Streptomyces) and Foliar Fertilization on Growth Response and Rhizosphere pH of Three Strawberry Cultivars

Abstract

Vegetatively propagated plants of three strawberry cultivars-‘Senga Sengana’, ‘Elsanta’ and ‘Kent’-were grown for 20 weeks in rhizoboxes filled with 1.85 kg of sterilized mineral soil. Ten plants were treated with an N-P-K foliar fertilizer (F, control), or inoculated with a substrate containing arbuscular mycorrhizal fungi, Trichoderma viride and rhizosphere bacteria (PGPR-Plant Growth Promoting Rhizobacteria) without any fertilization (M), or inoculated with the mixture of microorganisms and treated with the foliar fertilizer (MF). Total plant biomass was increased by the M treatment in all cultivars. M treatment resulted in higher total root length and number of root tips in ‘Senga Sengana’, whereas the other two cultivars showed different responses of root morphology. Shoot/root ratio was decreased by the M and MF treatments in comparison with control plants. Foliar fertilization of inoculated plants caused different growth responses in the three cultivars and a general decrease of root growth. After the MF treatment, the biomass of ‘Senga Sengana’ increased and the biomass of ‘Elsanta’ and ‘Kent’ decreased. Inoculation with the mycorrhiza-PGPR substrate increased rhizosphere pH irrespective of foliar fertilization. Plant mineral content was highly modified by the treatments in all the cultivars examined. In particular, changes were noted in N, P, K, Fe, B and Mn uptake. The results show an interaction between foliar fertilization and root inoculation with microorganisms, as well as genotype-dependent influences, on growth responses and rhizosphere pH of strawberry plants.     

Studies on the variability,inheritance, and inter-relationships of mineral macro-nutrients and micro-nutrients in strawberry (Fragariaananassa Duch.)

Summary

Strawberry (Fragaria ananassa Duch.) is a rich source of minerals, vitamins, and anti-oxidants, and has a unique flavour and aroma. However, there is little information on the genetic variability and inheritance of mineral elements in strawberry. This is important as it can influence the selection of better genotypes and suitable breeding approaches for improvements in the nutritional quality of fruit. The objectives of the present study were, therefore, to estimate the variability, inheritance, and inter-relationships of mineral elements, to identify mineral-rich and productive genotypes, and to suggest suitable breeding approaches. A significant genotypic mean square for all the minerals studied indicated sufficient variation among genotypes. Our results also indicated that the effect of genotype on the mineral content of fruit was stronger than that of environment. Six genotypes, namely ‘Ofra’, ‘Sweet Charlie’, ‘Elista’, ‘Festival’, ‘Camarosa’, and ‘Douglas’ were found to have higher mineral contents as well as better fruit yields, and therefore could be useful in further breeding programmes. N, K, Ca, Mg, Fe, Mn, Zn, and Cu contents, together with fruit yield, could be improved by selection and hybridisation as these traits showed high heritability (> 80%) and high genetic advance as a percentage of the mean (> 40%), while recurrent selection was suitable for increasing P contents, which showed moderate heritability (> 79.81%) and low genetic advance as a percentage of the mean (> 33.86%). Moreover, Mg and N contents could be used as reliable tools with which to identify the most productive and mineral-rich genotypes, as indicated by correlation and path analysis. Studies on such genetic estimates will increase our understanding of the inheritance of mineral contents and affect the design of crop improvement strategies.