Effect of biocontrol agent Bacillus amyloliquefaciens and 1-methyl cyclopropene on the control of postharvest diseases and maintenance of fruit quality

Efficacy of biocontrol agent Bacillus amyloliquefaciens PPCB004 was evaluated on the control of anthracnose and phomopsis rot in ‘Solo’ papaya pre-treated with 1-methyl cyclopropene (100 μl) (1-MCP) during storage. This treatment was compared to the untreated control, commercial treatment (washing in chlorinated water), stand alone 1-MCP and PPCB004 treatment. Although fruit pre-treated with 1-MCP delayed the ripening (100% yellow) after cold storage by 9-10 d, it showed higher incidence and severity of anthracnose and phomopsis rot than the fruit subjected to commercial treatment. Application of PPCB004 after 1-MCP pre-treatment (1-MCP + PPCB004) reduced the anthracnose and phomopsis incidence and severity after cold storage (10 °C, 85% RH for 14 d) and ripening at 25 °C. The 1-MCP + PPCB004 treatment helped to retain the fruit firmness, overall quality and uniform yellow skin (100%) and flesh colour after ripening. The PPCB004 was effectively recovered from stand alone PPCB004 and 1-MCP + PPCB004 treated fruit after cold storage and ripening. The PPCB004 population showed an increase by 1 log units after ripening in 1-MCP + PPCB004 treated fruit. After ripening the recovery of PPCB004 population was higher (0.7 log units) in 1-MCP + PPCB004. The total recovery of fungal population on the fruit surface after ripening was lower in 1-MCP + PPCB004 and stand alone PPCB004 treated fruit. It can be concluded that application of B. amyloliquefaciens PPCB004 with 1-MCP pre-treated papaya (at 25-30% skin yellow stage) can significantly reduce disease incidence associated with 1-MCP treatment. This treatment has the potential for commercial application in the ‘organic’ papaya industry.     

Effect of cultural practices and fungicides on Phytophthora fruit rot of watermelon in the Carolinas

Phytophthora fruit rot of watermelon, caused by Phytophthora capsici, is an important and emerging disease in Southeastern U.S.A. The effects of two cultural practices (raised bare ground and raised plastic mulched beds) used for growing watermelon and different fungicide treatments on development of Phytophthora fruit rot were evaluated. The experiments were conducted over three years (2005-2008) at research stations in North Carolina and South Carolina, U.S.A. Fungicides were applied at weekly intervals on the diploid cv. Mickey Lee for an average of five applications. Fruit rot incidence was recorded at the end of each experiment. Fruit rot incidence in the non-treated plots was 66% across two states and six trials. Overall, the levels of fruit rot on the raised bare ground and raised plastic mulched beds were not significantly different. Based on percent disease reduction relative to the non-treated check plots, the fungicide Captan was the most effective across years and locations (range = 23-70%, mean = 57%), followed by mandipropamid (25-65%, mean = 50%), fluopicolide (24-65%, mean = 43%) and cyazofamid (0-48%, mean = 31%). Mefenoxam, the current standard treatment reduced fruit rot by 8-28% (mean = 18%). The addition of copper hydroxide to the spray mix did not significantly enhance effectiveness of Captan or mandipropamid. The variability in fungicide efficacy observed in these experiments across locations and years demonstrates the importance of environmental conditions in disease development and management. Even when the most effective fungicides are used, heavy losses may occur when conditions are highly favorable for disease development. Ultimately, effective control of Phytophthora fruit rot of watermelon will require an integrated management strategy that includes well-drained fields, water management and crop rotation in addition to fungicides.     

Effect of thinning flower buds on fruit and seed traits and root yield of Panax ginseng C.A. Meyer

Panax ginseng C.A. Meyer, commonly known as ginseng, is a perennial herb. Agricultural practices have an influence on growth and yield of P. ginseng plants. Effect of thinning flower buds (treatment A (TA) the outermost whorl of flower buds in the umbels was retained while all other buds were excised; treatment B (TB) the two outer whorls of flower buds in the umbels) on fruit traits, which include number of fruits per plant, single fruit: double fruit ratio, fruit weigh (FW) per square meter, weight of 100 fruits, vertical length of fruit (VLF), horizontal diameter of the fruit (HFD) and thickness of the fruit (TF), seed traits, which include number of seeds per square meter, weight of 1000 seeds, number of different seed grading categories (extremely large seeds (ELS), large seeds (LS), medium-sized seeds (MS), small seeds (SS)) per square meter, vertical length of the seed (VLS), horizontal diameter of the seed (HSD), thickness of the seed (TS), and the root yield and total ginsenosides content of root of four- and five-year-old cultivated P. ginseng was studied in Fusong region of north-eastern China. The results showed that the FW and VLF, the weight of 1000 seeds, number of ELS per square meter, VLS and HDS of ELS, HDS and TS of MS and root yield were increased significantly by TA and TB (p < 0.05), whereas the number of MS and SS were significantly reduced (p < 0.05) in four- and five-year-old plants. The number of ELS and LS in TB and control were higher than that of in TA, and not significant was observed between TB and control. The root yield in TB was significantly higher than that in control of five-year-old plants. Number of the seeds per square meter of five-year-old plants was higher than that of four-year-old plants. The results indicated that the method of thinning flower buds, which was the two outer whorls of flower buds in the umbels, on five-year-old cultivated P. ginseng plants was a favourable method to promote the production of high-quality seeds and maximise the root yield.     

Losses in litchi at various stages of supply chain and changes in fruit quality parameters

During May and June of 2012 and 2013, a study was conducted to assess losses at the farm, wholesale and retail levels in the supply chain of litchi in India. Changes in fruit quality parameters after harvest and the effectiveness of an improved corrugated fibre board (CFB) box versus conventional wooden box packaging to minimize postharvest losses were also studied. Farm-level samples were collected immediately after harvest from farmers' orchards in the Muzaffarpur district of Bihar state. Wholesale market samples were procured from the Delhi market, and retail samples from the Muzaffarpur and Delhi market. Real-time data on losses and quality parameters of fruits were recorded by transporting litchi from Muzaffarpur to Delhi (distance 1000 km) by truck. Studies indicated that the average loss (fruits discarded at sorting) apparent at the farm level during 2012 and 2013 was 30.4% and 25.8%, respectively. The average loss at the wholesale market level in Delhi was 15.8% and 12.4% during 2012 and 2013, respectively. The highest mean loss (up to 20.5%) was observed at the retail level. The mean fruit weight loss during transport to Delhi was 9.42% and 7.07% during 2012 and 2013, respectively. The mean total loss in the supply chain of litchi ranged from 35.3% to 43.8%. The total soluble solids, respiration and ethylene evolution in litchi fruits were found to increase after transport, whereas acidity and colour parameters (L*, a* and b* values) significantly decreased over time. The predominant pathogen associated with fruit decay was Alternaria alternata (Fr.) Keissler. CFB packaging significantly reduced various losses, thus indicating its effectiveness in its current use in non-refrigerated trucks for transport.     

Combination effect of chitosan and methyl jasmonate on controlling Alternaria alternata and enhancing activity of cherry tomato fruit defense mechanisms

The effect of chitosan treatment alone or in combination with methyl jasmonate (MeJA) against Alternaria alternata in vitro and in vivo, and defense related enzyme activities were investigated. 100–500 μl/l MeJA significantly inhibited mycelial growth of A. alternata. The inhibitory activity of MeJA on mycelial growth, spore production, spore germination and germ tube length of A. alternata in vitro could be enhanced by 0.1% chitosan. The combination of 0.1% chitosan and 500 μl/l methyl jasmonate was more effective to reduce the disease incidence and lesion diameter of postharvest decay of cherry tomato than the application of MeJA or chitosan alone. The combined treatments resulted in higher activities of PPO (polyphenol oxidase), POD (peroxidase) and PAL (phenylalanine ammonialyase) than the control. This work indicated that the combination of chitosan and methyl jasmonate is a promising method to control postharvest decays of fruit and vegetables.     

Bird damage to select fruit crops: The cost of damage and the benefits of control in five states

Fruit loss to birds is a long-standing and costly problem for many producers. We conducted a survey of Honeycrisp apple, blueberry, cherry, and wine grape growers in California, Michigan, New York, Oregon, and Washington to estimate costs of bird damage and benefits of bird damage management. We also assessed grower perceptions of impacts on profits and effectiveness of bird management techniques. Current yield-loss estimates provided by growers and market price data were used to monetize current bird damage in each crop and growing region. Data on expected damage without management were used to estimate the benefits of bird damage management as it is currently being employed in the different crops and growing regions. We estimated that current bird damage costs per hectare ranged from $104 in Oregon tart cherries to $7267 in Washington Honeycrisp apples. Estimated benefits of bird management ranged from $299 per hectare in Oregon tart cherries to $36,851 in California blueberries. Aggregate bird damage in the five crops and states was estimated at $189 million, and the aggregate benefits of managing that damage were estimated at $737 million to $834 million. Growers viewed most techniques for bird damage management as ineffective, or only slightly effective, and a majority of blueberry and sweet cherry growers viewed bird damage as having a significant impact on profits. Enhancing the effectiveness of bird damage management would increase both the efficiency and profitability of fruit production.     

不同果袋对‘蜜丝枣’果实品质及抗氧化酶活性的影响

以毛叶枣品种‘蜜丝枣’为试材,分析无色透明薄膜袋、白色无纺布袋、白色单层纸袋、外黄内黑双层纸袋4种果袋对‘蜜丝枣’果实品质及抗氧化酶POD、CAT活性的影响。结果表明:套袋能明显改善‘蜜丝枣’果实的外观色泽,提高果实抗氧化酶POD、CAT活性;套袋在一定程度上影响了‘蜜丝枣’果实的内在品质,降低了果实风味。套袋后,在4种果袋中,只有无色透明薄膜袋可以显著提高果实的单果重(比对照提高22.1%),而套其他3种果袋却会不同程度抑制果实生长,导致单果重不同程度下降;套无色透明薄膜袋对果实的内在品质影响程度最小,仅降低了可溶性固形物和可滴定酸,而对可溶性总糖无显著影响,对维生素C含量略有提高。综合套袋对果实品质和商品性的影响,推荐‘蜜丝枣’果实套袋材料为无色透明薄膜袋。     

模拟酸雨对花生种子萌芽及幼苗生长的影响

以人工模拟酸雨试验研究不同酸度酸雨对花生种子萌发和幼苗生长的影响，试验结果表明，pH值4．5以下的酸雨可显著地降低花生种子的发芽率，使胚根长度变短，活力指数下降，高酸度的模拟酸雨胁迫使花生幼苗叶总数显著减少，叶片出现明显的受害症状，pH值2．5的模拟酸雨胁迫使叶绿素含量明显下降，过氧化氢酶活性显著增强，酸雨还对土壤具有酸化作用。     

不同套袋时期和果袋类型对云红梨1号果实品质的影响

【目的】明确云南地区红色砂梨适宜的套袋时间和果袋类型。【方法】以红色砂梨品种云红梨1号为试材,以4种果袋分2个时期对云红梨1号进行套袋试验.【结果]云红梨1号在云南地区适宜的套袋时间为4月25日。用外灰内黑薄膜双层袋套袋可显著提高梨果的着色指数和果实可溶性固形物,用外黄内黑双光蜡袋套袋能减少果锈的形成,显著提高梨果的着色指数。适宜的纸袋类型为外黄内黑双光蜡袋。【结论】适宜的套袋时期和果袋类型有利于果品质量的提高。     

模拟酸雨及其SO42-离子对油菜生长及品质的影响

通过大田试验,以秦优7号油菜品种为供试对象,初步研究了南京地区硫酸型模拟酸雨及其SO42对油菜生长及品质的影响。结果表明,pH>4.0时,主要表现为酸雨中SO42-离子对油菜的株高和叶面积的促进作用,最大值出现在pH5.0的处理组。只有在强酸性酸雨（pH<4.0）的胁迫下油菜的株高和叶面积才会随酸度的增强而减少。叶绿素含量受酸雨酸度的影响比较显著,尤其是叶绿素a,其含量与酸雨的 pH值呈显著正相关。pH>4.0时,酸雨中植物硫素的供给对油菜籽产量有促进作用;但在极酸性条件下,酸雨是胁迫因子,导致产量显著下降,但对千粒重并无显著影响。此外,模拟酸雨对油菜籽粗脂肪、蛋白质、可溶性糖和还原性糖含量表现出显著胁迫,对水溶性氨基酸有促进作用,但与酸雨酸度之间没有明显的线性相关性,总酸度与酸雨pH值呈二阶相关关系。     

Evaluation of thiacloprid and clothianidin (neonicotinoids) as alternative to fenthion (organophosphate) for control of Mediterranean fruit fly (Diptera: Tephritidae) in deciduous fruit orchards

Fenthion (organophosphate) was used in Australia to target adults, eggs and larvae of Mediterranean fruit fly (Medfly), Ceratitis capitata Wiedmann (Diptera: Tephritidae) in deciduous fruits. With its removal from use in 2015, clothianidin and thiacloprid (neonicotinoids) were evaluated for any adulticide, ovicide or larvicide (eggs, larvae) activity against Medfly in a series of laboratory and field-cage experiments in peach and nectarine. We included fenthion in all experiments as a positive control. As an adulticide, fenthion had the greatest residual toxicity on fruit, with 7 d old residues killing 44% of adults within 48 h compared to thiacloprid (17%) and clothianidin (30%). When applied as a larvicide to naturally infested peaches, none of the insecticides was 100% effective, though fewest pupae (1.18 ± 0.19 pupae/fruit) (indirect measurement of larval survival) were produced when treated with fenthion, followed by clothianidin (3.40 ± 0.33 pupae/fruit) and thiacloprid (6.88 ± 0.34 pupae/fruit); with 11.35 ± 0.30 pupae/fruit in control (water). In peaches treated 48 h post-infestation, fenthion was most effective in reducing numbers of pupae and adult emergence and with higher percentage of deformed adults, with thiacloprid=clothianidin. In nectarines treated 48 h post-infestation, fenthion was most effective in reducing numbers of pupae and adult emergence as well as with higher percentage of deformed adults, followed by clothianidin. Insecticides were least effective when applied as a preventative 24 h or 7 d prior to infestation, with fenthion more effective than clothianidin. Whilst our study shows that neither clothianidin nor thiacloprid are equivalent to fenthion, they are acceptable substitutes to growers for use for Medfly in deciduous fruits given that fenthion is no longer available to growers in Australia. We recommend that growers incorporate other controls to target the adult stage rather than rely only on new insecticides.     

Effect of Pichia membranaefaciens on ROS metabolism and postharvest disease control in citrus fruit

The yeast Pichia membranaefaciens has antagonistic effects against a wide range of phytopathogenic fungi that cause postharvest fruit decay. This work evaluated the effects of P. membranaefaciens on the reactive oxygen species (ROS) metabolism and disease control in harvested citrus fruit (Citrus sinensis L. Osbeck). The lesion diameter caused by Penicillium italicum and Penicillium digitatum on citrus fruit was remarkably reduced when the fruit was point-inoculated or dipped in a suspension of P. membranaefaciens at 1 × 10⁸ CFU mL⁻¹. The application of P. membranaefaciens on citrus fruit enhanced the activity of superoxide dismutase, ascorbate peroxidase, and glutathione reductase, as well as the levels of hydrogen peroxide, the superoxide anion and glutathione, but inhibited the decreasing ascorbic acid content. Furthermore, catalase activity was decreased by the same treatment. These results indicated that yeast treatment induced the synthesis of antioxidant enzymes which might have antagonistic effects against postharvest green and blue mold infection in citrus fruit.     

Effects of fruit dipping in hydrochloric acid then rinsing in water on fruit decay and browning of longan fruit

The objective of this study was to find alternative methods for the control of pericarp browning in longan fruits (Dimocarpus longan Lour.) cv. Daw in order to replace the use of sulfur dioxide (SO₂). Experiments were conducted by dipping fruits in 1.5 N HCl solution (pH 0.21) for 20 min followed by draining. The effects of subsequent rinsing in water were also investigated. Untreated fruits and SO₂ fumigated fruits were used as controls. Fruits from each treatment were then packaged in commercial perforated plastic baskets and stored at 3 ± 1 °C, 85% RH for 60 days. It was found that dipping the fruits in HCl controlled disease development compared with the untreated fruits. In addition, dipping the fruits in HCl as well as fumigating with SO₂ gave the best control of pericarp browning. After 5 days, the pericarp of untreated fruits became brown. Dipping fruits in HCl without rinsing reduced pericarp and juice pH and increased titratable acidity which lowered eating quality. Sensory analysis was carried out to determine aril color as well as appearance, firmness, flavor and taste. Dipping in 1.5 N HCl for 20 min and rinsing exhibited higher efficacy than dipping for 0, 10 or 15 min in controlling fruit decay and maintaining fruit color and eating qualities during 7 days storage at 25 °C following 45 days storage at 5 ± 1 °C. Therefore, dipping in 1.5 N HCl for 20 min, followed by rinsing in water can be considered for commercial application in extending shelf life, decreasing fruit decay and maintaining fruit quality of longan fruits.     

不同薄膜覆盖对冬季茶树扦插发根率的影响

在扦插苗圃用不同颜色的塑料薄膜进行覆盖 ,观察地温、气温和空气湿度的变化对扦插苗发根的影响。结果表明 ,用薄膜覆盖的茶苗发根率比对照高十几倍 ,各种薄膜处理的发根效果以黄色膜 >红色膜 >黑色膜 >白色膜 >蓝色膜 ,地温和湿度与茶苗发根的相关系数显著。     

施用木薯酒精厌氧发酵液对香蕉生长发育及土壤肥力的影响

为探索木薯酒精厌氧发酵液作为部分灌溉用水及肥源替代化肥在香蕉生产的应用效果,以常规施肥作为对照,研究木薯酒精厌氧发酵液（COD值为1 100～1 300 mg/L）不同施用量对香蕉生长发育及蕉园土壤肥力的影响。结果表明,施用木薯酒精厌氧发酵液能促进香蕉生长发育,显著提高产量和果实品质,改善土壤肥力,最佳淋施量为750 t/hm2,较常规施肥,产量增加了19.80％,果实Vc含量、可溶性总糖和可溶性固形物含量分别提高了28.19％、5.22％和8.98％,土壤碱解氮、有效磷、速效钾和交换性钙含量分别提高了12.76％、267.40％、53.51％和2.10％。表明木薯酒精厌氧发酵液可作为优良的液体肥料和土壤改良剂应用于香蕉生产。     

Effect of waxing and cellophane lining on chemical quality indices of citrus fruit

Effects of waxing of the fruit and of the use of cellophane for lining storage boxes on chemical quality indices (including ethanol and acetaldehyde) and flavour scores of Feutrell's Early mandarin during storage at room conditions were determined. Maximum changes during storage of waxed mandarins in film-lined boxes occurred in ethanol contents which were followed by acetaldehyde, total soluble solids (TSS)/acid ratio, TSS and acid contents. There were negative and highly significant linear relationships between flavour scores, and ethanol content and acetaldehyde content. The r² values indicated that over 90% of the variation in flavour scores could be explained by changes in ethanol and acetaldehyde contents whereas only 50% of the variation in flavour scores could be predicted by changes in total acid and TSS/acid ratios. There were comparatively greater increases in ethanol and acetaldehyde content, lesser increases in TSS and greater decreases in total solids of waxed mandarins during storage than those of unwaxed fruits stored in film lined boxes; the ratio of ethanol and acetaldehyde (E/A) of waxed mandarins was also higher. Decreases in citric acid content during storage correlated linearly to increases in the E/A ratio at the 1% level of significance indicating that citric acid metabolism was affected during storage of waxed mandarins at ordinary room conditions.     

覆膜与钾肥互作对油葵产量和钾肥利用效率的影响

为了获得半干旱区油葵高产高效的最佳栽培措施,2015-2017年以油用向日葵（陇葵杂3号）为材料,研究3个覆膜栽培条件及4个钾肥水平条件下的油葵产量和钾肥利用效率。3个栽培模式分别为露地、全膜双垄沟播、全膜双垄沟播+补灌。4个钾肥水平分别为0、48、84和120kg/hm2。调查籽粒产量和干物质积累,计算钾肥吸收利用,结果表明：覆膜与钾肥互作显著影响籽粒产量、干物质积累和钾肥利用效率,且两者互作效应显著;栽培方式对上述三者的影响均表现为全膜双垄沟播+补灌＞全膜双垄沟播＞露地,且差异显著;与露地相比,全膜双垄沟播+补灌和全膜双垄沟播处理油葵籽粒产量、钾肥利用效率分别显著提高了170.1%和103.9%、184.3%和143.7%。各施钾处理籽粒产量和器官干物质积累量均显著高于不施钾,表现为K120＞K84＞K48＞K0,施钾处理间除120与K84外,籽粒产量和干物质积累量差异显著。钾肥偏生产力随施钾量的增加而下降,钾肥农学效率和钾肥利用效率则先升高后降低,以84kg/hm2时钾肥农学效率和钾肥利用效率最大。油葵产量与钾肥农学效率和利用效率协同提高。综上认为,在本试验条件下,全膜双垄沟播栽培和施钾量为84kg/hm2是半干旱区油葵适宜种植模式,且补灌效果明显。      

Effect of pre-harvest calcium chloride applications on fruit calcium level and post-harvest anthracnose disease of papaya

Anthracnose disease of papaya, caused by Colletotrichum gloeosporioides Penz, can cause extensive postharvest losses. The goal of this research was to use pre-harvest calcium applications to reduce anthracnose disease. Six pre-harvest foliar calcium sprays were applied biweekly to papaya trees in experimental orchards at Universiti Putra Malaysia. Additional in vitro and in vivo tests were carried out to test the effect of calcium on fruit calcium content, spore germination, mycelial growth and disease severity. Calcium chloride at 1%, 1.5% and 2.0% concentrations significantly decreased spore germination. Calcium content of papaya fruit was significantly increased by calcium sprays at a concentration of 2.0% in 2012 and 2013. In vivo studies showed that increasing calcium content in fruit by calcium sprays at 1.5 and 2.0% concentrations significantly reduced anthracnose incidence of fruits during five weeks storage at 12 ± 2 °C, and delayed initiation of disease symptoms by four weeks.     

不同时期套袋对菠萝果实发育和品质的影响

以菠萝品种‘无刺卡因’为试材,分析了不同套袋时间对果实发育和品质的影响。结果表明,套袋可以防止日灼的发生,提高果实的外观质量。但是,套袋处理会降低果实可溶性固形物、可滴定酸、可溶性糖、可溶性蛋白、类黄酮含量,导致果实风味品质下降。套袋过早,平均单果重明显减少,而较晚时期的套袋会提高维生素C和总酚的含量,最适宜的套袋时期为谢花后40～60 d。     

东北低温多湿气候对大豆病虫草害发生的影响及对策

2010年人春以来,东北地区持续出现大范围降雪和持续低温天气,从物候和节气看比常年推迟10～15天。4月下旬,大部分农田因田间过于泥泞而无法展开春耕播种工作,仅有少量岗地、阳坡地开始灭茬整地,部分农田积雪尚未完全融化,对春耕生产造成较大影响。