White mould of sweet basil: conditions influencing its development in greenhouses and cultural measures for disease management

During the winter season, Sclerotinia sclerotiorum infects the stem bases of greenhouse‐grown sweet basil plants and, in severe epidemics, it may also infect the shoots. Sclerotia of S. sclerotiorum, and the ascospores that are released from the apothecia that form on them, serve as the inoculum for white mould epidemics. This research aimed to identify cropping parameters associated with lower incidence of white mould in a survey of the main basil‐growing region in Israel, and study cultural methods that might suppress the disease. The survey revealed that this mould, in the main growing area in Israel, has one cycle of infection. Factors associated with increased moisture in the greenhouse were found to be associated with increased levels of the disease. The use of a lower planting density reduced the incidence of white mould in semi‐commercial experimental plots, as well as the severity of the disease on shoots infected by S. sclerotiorum after harvest, in comparison to the commonly used higher planting density, with no negative effect on yield. Mulching the beds with polyethylene effectively reduced disease, and a combination of polyethylene mulch and increased plant spacing reduced disease severity on cut shoots in a synergistic manner. In conclusion, cultural control methods reduced disease incidence under field conditions and severity of the disease on cut shoots.     

Reduction of Botrytis cinerea sporulation in sweet basil by altering the concentrations of nitrogen and calcium in the irrigation solution

Current measures for suppressing grey mould ( Botrytis cinerea ) on sweet basil rely on fungicide applications and climate control. In this study, the nitrogen and calcium concentrations in the standard irrigation solution (7·2 and 1·3 m m , respectively) were varied in a series of experiments conducted in pots and large containers. Treatments differed in the N or Ca concentrations supplied, and effects on host response were determined in detached stem segments, individual plants and plots. Effects of the two elements on grey mould incidence, lesion size and rate of disease progression were erratic and rarely significant, but decreasing the concentration of N and increasing the concentration of Ca in the irrigation solution decreased sporulation of B. cinerea . In some cases, however, altering the standard irrigation solution resulted in significantly lower yields. Analyses of mineral contents in the shoots suggested that yields were not impaired when N content in the shoots was not reduced below 2·9% and Ca content was not raised above 1·3%. These findings were used to compose a modified irrigation solution containing half of the N (3·6 m m ) and double of the Ca (2·55 m m ) concentrations in the standard irrigation solution. The modified irrigation solution significantly reduced sporulation of B. cinerea without affecting crop yield.     

The use of antioxidants (free radical scavengers) to control grey mould (Botrytis cinerea) and white mould (Sclerotinia sclerotiomm) in various crops

Eighteen free radical scavengers (antioxidants) were tested for their ability to control grey mould. Most of the compounds reduced disease significantly in at least one of the test hosts–leaves of tomato, pepper, Senecio sp., bean, eggplant, or rose flowers; however, the effective concentration varied between 0.1 and 100 m m . Selected antioxidants were tested further. Butylated hydroxy toluene (BHT), tannic acid, ascorbic acid and dimethyl sulfoxide (DMSO) at a concentration of 1 .0 m m controlled grey mould of tomato fruits. All these compounds except BHT controlled the disease on cucumber fruits. Antioxidants affected Rhizopus stolonifer on grape berries but not Botrytis cinerea or Aspergillus spp. Some combinations of antioxidants were found to be more effective than either compound alone when tested on pepper or tomato. The synergists ascorbic acid and citric acid improved the control activity of BHT, propyl gallate, benzoic acid and tert -butylhydroquinone on tomato leaves. Ethylene production was inhibited in tomato leaves treated with propyl gallate, ascorbic acid and benzoic acid, but not in pepper leaves. Ethephon or H₂O₂ increased the severity of grey mould on leaves of Senecio sp. Their effect was controlled by BHT and benzoic acid or by BHT, respectively. Four to six compounds reduced linear growth of B. cinerea isolates in culture at a concentration of 1.0 m m , and six more compounds were effective at 10.0 m m . However just five compounds inhibited conidial germination at the high concentration alone. Gluconic acid lactone, thiourea and propyl gallate reduced Sclerotinia sclerotiomm on lettuce by 51-76%. The multiple activity of antioxidants on the host plant interaction is discussed.     

仙客来灰霉病田间消长规律及防治技术

通过田间观察,3月下旬至4月下旬移栽入盆的仙客来,5月下旬出现灰霉病病株,9月下旬发病逐渐加重,12月下旬至2月上旬为发病高峰期。种植环境和种植密度与发病有关,品种间发病有差异,生物农药农抗武夷菌素、多抗霉素、春雷霉素和化学农药腐霉利对仙客来灰霉病有较好的防治效果。     

人参灰霉病拮抗细菌的筛选及鉴定

为获取对灰葡萄孢Botrytis cinerea Pers.ex Fr.防效优良的菌株,采用滤纸片法和牛津杯法从105株菌株中筛选出7株拮抗性良好的菌株,采用平板对峙法对抑菌效果较好的菌株SZ-35进行抑菌谱测定,采用盆栽法研究其对人参灰霉病的防效及在人参体内的定殖能力,并通过形态学、生理生化特征、16S rDNA及gyrB基因测序确立其分类地位。结果显示,菌株SZ-35对灰葡萄孢的抑制作用最强,抑菌率和抑菌带宽分别为86.53%和12.20 mm,且具有广谱抑菌能力;菌株SZ-35可有效定殖于人参体内,对人参灰霉病的防效达76.42%,显著高于70%代森锰锌可湿性粉剂;通过形态特征、生理生化特征观察,以及16S rDNA及gyrB同源性序列对比分析,鉴定菌株SZ-35为解淀粉芽胞杆菌Bacillus amyloliquefaciens(GenBank登录号为KC511113)。研究表明,解淀粉芽胞杆菌SZ-35对灰葡萄孢具有良好的抑菌能力,且在人参中的定殖能力较好。     

Poacic acid suppresses dollar spot and snow mould in amenity turfgrass

Plant-based antifungal agents offer an alternative to synthetic fungicides in amenity turfgrass disease management. Poacic acid is a by-product of the biofuel production process that has exhibited antifungal activity, and the objective of this research was to determine its ability to serve as an effective management tool for economically important turfgrass diseases such as dollar spot and snow moulds. In vitro and field tests were conducted in Wisconsin and Michigan, USA from 2015 to 2017 to determine the efficacy of poacic acid in suppressing the economically important turfgrass pathogens Clarireedia jacksonii and Microdochium nivale. Poacic acid demonstrated strong antifungal activity against both pathogens in vitro, inhibiting growth of C. jacksonii and M. nivale by 93% and 74% relative to nonamended media, respectively. Poacic acid reduced dollar spot in the field in one of two years, but failed to suppress snow mould when applied alone. Poacic acid was an effective mix partner for snow mould control when combined with a synthetic fungicide, an important attribute because no single fungicide currently on the market provides acceptable snow mould control under heavy disease pressure. Future research should focus on improving poacic acid field efficacy so that it can be incorporated into plant-based disease management strategies for amenity turfgrass.     

Heat treatment for the control of rose and carnation grey mould (Botrytis cinerea)

Thermal dip treatment for flower heads was found effective against grey mould of roses. Dipping of flowers in tap-water at 50 C for 20 40 s was more effective than at higher or lower temperatures and than for longer treatments. The treatment was effective in five out of six rose cultivars and in one carnation cultivar. A 60, reduction in disease severity following the treatment was observed in flowers naturally infected by Botrytis cinerea, whereas the treatment was not effective against artificial infection of flowers. Conditioning of flowers for 2 days at 10 C and high relative humidity before incubation under grey-mould-conducive conditions (15 C. high humidity) increased the efficacy of the thermal treatment. Moreover, the combination of heat with 3 mM catechol was additively more efficient in reducing grey mould. The surfactant Tween 20 (001 %) improved the effect of treatment at 45 C for 20 s. A combination of heat with the fungicide chlorothalonil did not improve effectiveness, whereas when polyoxin B was combined with heat it was better than either treatment alone. The temperature of petals at the edge and centre of flower reached 37 and 27 C, respectively, at the end of a 20-s incubation period in 50 C water. Conidia treated at 34-40 C for 10-20 s incited 60% less severe disease than conidia treated at 25 C in water.     

Selection and evaluation of phyllosphere yeasts as biocontrol agents against grey mould of tomato

Phyllosphere yeasts antagonistic to the infective activity of Botrytis cinerea were isolated from leaves of greenhouse-grown tomatoes and evaluated in a detached leaf assay for their ability to suppress grey mould. Nine of 30 recovered yeast isolates were found to reduce a disease index by >90% when compared to an untreated control. In greenhouse experiments, the yeast isolate Rhodotorula glutinis Y-44 was the most efficient in controlling grey mould of tomato plants. In further experiments in greenhouse-grown tomato plants the effectiveness of R. glutinis Y-44 was compared with two commercial fungicides. It was demonstrated that R. glutinis Y-44 was as effective as fungicides in controlling the pathogen. Moreover, the population of R. glutinis Y-44 was monitored for 8 weeks after application on tomato plants. The isolate successfully colonized the plant surface, although the population decreased by 10-fold 8 weeks after application. Since B. cinerea is also a major post-harvest pathogen for tomato fruits, the ability of R.␣glutinis Y-44, to protect artificially infected wounded tomato fruits was also tested. It was shown that R.␣glutinis Y-44 was able to reduce by 50% the percentage of infected wounds compared to the untreated controls.     

Characteristics of infestation of sweet potato by sweet potato weevil Cylas formicarius (Coleoptera: Apionidae)

Studies were conducted to examine the characteristics of infestation of vines of sweet potato plants by the sweet potato weevil, Cylas formicarius (F.). The use of terminal tender vine cuttings, taken even from heavily weevil‐infested sweet potato, to grow a new crop and planting such a crop in plots surrounded by barriers to reduce weevil migration from the outside to the newly planted area, produced a practically weevil‐free crop. On the contrary, crop planted to old vine cuttings in an open field was severely damaged by the weevil. Consequently, crop planted using tender vine cuttings produced significantly more root yield than the one planted to old vine cuttings, irrespective of whether the planting was done in an open field or in an insect‐protected field. Sweet potato weevil infestation of 1‐ to 8‐week‐old plants increased significantly with plant age. The insect preferred sweet potato roots over sweet potato vines when both plant parts were available for infestation. Dipping the vine cuttings for 30 min in carbofuran solution prior to planting protected the newly planted sweet potato crop for up to 6 weeks after planting.     

芽胞杆菌JZB30-1的鉴定及其对番茄灰霉病的生防作用

为获得对番茄灰霉病具有良好防效的生防芽胞杆菌, 采用对峙培养、双层平板以及生防相关特性检测等方法筛选高活性拮抗菌株, 根据形态学、生理生化特性及多基因测序进行菌株种类鉴定, 通过离体果实和盆栽试验明确供试菌株的防病促生效果。结果表明, 芽胞杆菌JZB30-1对番茄灰霉病菌等10余种植物病原真菌和细菌具有广谱抑菌活性; 该菌株具有合成蛋白酶、纤维素酶、脂肽类物质,分泌铁载体、生长激素及溶磷等特性, 经鉴定其为解淀粉芽胞杆菌Bacillus amyloliquefaciens; 菌株JZB30-1无菌发酵滤液50倍液喷施处理, 对番茄果实灰霉病防效为95.0%, 发酵液10倍稀释液灌根, 番茄株高、鲜重分别较对照增加25.7%和28.4%。相关结果为利用解淀粉芽胞杆菌JZB30-1进行番茄灰霉病生物防治提供理论依据。     

叶面喷施镁肥对缺镁番茄养分吸收和分配的影响

针对近年来北方日光温室中栽培番茄缺镁普遍发生和日益严重的问题,研究了叶面喷施MgSO_4、Mg(NO3)2及不同施用量对秋冬茬缺镁番茄K、Ca、Mg吸收和分配的影响,以期为番茄缺镁的矫正提供科学依据。结果表明:(1)随番茄生育进程各处理番茄叶片Mg和K含量呈下降趋势,Ca含量先下降后基本稳定,其中,Mg和Ca以第1穗果膨大期到第2穗果膨大期下降幅度最大,降幅分别为17.8%和39.1%。(2)喷施Mg肥显著提高叶片中Mg的浓度及携出量,喷施含镁0.4%的MgSO_4·7H_2O溶液叶片镁含量及携出量较对照分别提高了1.55和1.78倍,而对根、茎和果实中Mg的浓度及携出量无明显影响;从产量上看,喷施含镁0.2%和0.4%MgSO_4·7H_2O及0.2%Mg(NO3)2·6H_2O溶液与不喷施相比产量分别提高了8.0%、8.9%和5.3%,但差异不显著。(3)土壤交换性K/Mg均大于适宜值,K、Mg养分比例严重失调,而石灰性土壤养分失调后叶面补施Mg肥,Mg从叶片向其他部位的转运有限,必须降低钾肥施用量,使养分平衡供应。     

Identification of tea foliar diseases and pest damage under practical field conditions using a convolutional neural network

Lesions of tea (Camellia sinensis) leaves are detrimental to the growth of tea crops. Their adverse effects include further disease of tea leaves and a direct reduction in yield and profit. Therefore, early detection and on-site monitoring of tea leaf lesions are necessary for effective management to control infections and prevent further yield loss. In this study, 1,822 images of tea leaves with lesions caused by three diseases (brown blight, Colletotrichum camelliae; blister blight, Exobasidium vexans; and algal leaf spot, Cephaleuros virescens) and four pests (leaf miner, Tropicomyia theae; tea thrip, Scirtothrips dorsalis; tea leaf roller, Homona magnanima; and tea mosquito bug, Helopeltis fasciaticollis) were collected from northern and central Taiwan. A faster region-based convolutional neural network (Faster R-CNN) was then trained to detect the locations of the lesions on the leaves and to identify the causes of the lesions. The trained Faster R-CNN detector achieved a precision of 77.5%, recall of 70.6%, an F1 score of 73.91%, and a mean average precision of 66.02%. An overall accuracy of 89.4% was obtained for identification of the seven classes of tea diseases and pests. The developed detector could assist tea farmers in identifying the causes of lesions in real time.     

O3对日光温室黄瓜病虫害的防治效果

通过室内与大田试验，明确O3对日光温室黄瓜病虫害的防治效果。研究结果表明，在病害发生初期，用O3发生器隔天施放O3，每天施放3次，每次40min，间隔20min，O3浓度维持约1mg／kg，施放后7天，对黄瓜霜霉病、白粉病、细菌性角斑病及灰霉病防治效果分别为63．4％、53．6％、68．7％和65．0％。室内施放O3 60s，间隔20min，持续12h，对温室白粉虱、南美斑潜蝇成虫杀伤力为100％。O3对黄瓜植株安全，但随着黄瓜生育期的推进，对O3的忍受能力依次减弱。苗期忍耐O3最大浓度为1～2mg／kg，结果期0．4～1mg/kg，后期0．2～0．4mg／kg。O3防治黄瓜病虫害新技术具有安全、有效、方便、无二次污染等特点，尤其在黄瓜定植前对棚室进行大剂量消毒，可不留死角，且有效地解决了硫磺等药物消毒所造成棚内一些设施的破坏及对生态环境污染的难题，具有广阔的推广应用前景。     

新杀菌剂对番茄灰霉病菌的室内毒力及田间防效

室内采用菌丝生长速率法、孢子萌发法和黄瓜子叶法测定了咯菌腈、抑霉唑、福美双、吡唑醚菌酯和嘧霉胺对番茄灰霉病菌( Botrytis cinerea)的抑制作用。结果表明,菌丝生长速率法和孢子萌发法的测定均以咯菌腈毒力最高,EC 50分别为0.005 2 μg/mL和0.087 6 μg/mL;黄瓜子叶法测定以抑霉唑毒力最高,其EC 50为0.675 3 μg/mL。田间药效试验结果表明：50%咯菌腈可湿性粉剂90 g/ hm2对番茄灰霉病的田间防效达到90%以上,显著高于对照药剂50%啶酰菌胺水分散粒剂300 g/hm2和40%嘧霉胺悬浮剂 480 g/hm2的防效。     

湖北省设施番茄灰霉病发生规律及流行因子分析

为探索湖北省设施番茄灰霉病的发生规律,揭示不同流行因子与番茄灰霉病发生的关系。于2013-2016年在湖北省武穴市吴谷英村番茄种植基地选取代表性番茄大棚进行调查和取样检测,结果表明:湖北省设施番茄叶片和花朵带菌率变化起伏较大,带菌率分别为0～90.0%和0～100.0%;叶片带菌率在3月下旬到4月中下旬和5月中下旬是高峰期;花朵带菌率在4月中旬和5月中下旬达到高峰期,总体上花朵带菌率较高。番茄不同组织灰霉病的发病时间不同,叶片首先开始发病,花、果实、茎秆再逐渐发病,花朵和果实的发病率相对较高,叶片和茎秆发病率较低;花朵和果实发病率均在5月中旬至6月初达到最大值,茎秆发病率于5月下旬至6月上旬达到最高值,叶片无明显发病高峰期。果实、叶片、花朵和茎秆的发病率分别为0～42.0%、0～24.7%、0～100.0%和0～32.0%。番茄叶片发病率、花朵发病率、茎秆发病率和相对湿度均与果实发病率呈显著相关;通过预测模型检验表明相对湿度和叶片发病率所建模型预测值和实际值符合程度较好。在湖北省设施番茄大棚中,叶片发病率、花朵发病率、茎秆发病率和相对湿度对番茄果实发病影响最为显著,在防治过程中应及时摘除发病组织,调控棚内环境条件,预防灰霉病发生。     

陕西省主要作物灰水足迹时空变化特征研究

以陕西省为例,运用灰水足迹理论,对陕西省2000―2018年间主要作物灰水足迹的时空变化趋势和分布状况进行研究分析.结果表明:小麦、玉米、油料作物、大豆、蔬菜、水果多年生产灰水足迹均值分别为0.472、0.231、0.639、0.532、0.087、0.199 m3·kg-1;研究期间作物生产灰水足迹年际变化整体呈下降...     

50%氯溴异氰尿酸可溶粉剂土壤处理对作物土传病害防控效果研究

熏蒸剂因其较高的生物活性和广谱性而被广泛用于防治土传病害、杂草和线虫等,但其同时对土壤中的微生物也不可避免地会产生一定影响。土壤微生物作为土壤健康状况的评判标准之一,数量庞大,种类丰富,且在养分循环及元素转换等过程中均发挥着重要作用,因此研究熏蒸剂对土壤微生物的影响极为必要。文章阐述了氯化苦、棉隆、威百亩及二甲基二硫等几种常用熏蒸剂对土壤中微生物数量、多样性、群落组成结构、优势菌群以及氮循环功能微生物等的影响,旨在为理解熏蒸后土壤微生物的演替提供理论基础。经文中所列出的6种熏蒸剂熏蒸处理土壤后,土壤微生物的多样性均在短期内出现下降,其群落组成结构发生较大变化,且氮循环功能微生物在短期内受到明显抑制。     

灰色系统理论在植物病虫害预测中的应用

植物病虫害的综合管理是一个多因素的复杂系统，针对这一特点，本文全面阐述了灰色系统模型的建立与预测方泫，建立了植物病虫害测报中的GM(1，1)模型，测报准确性较高，模型模拟检验精度达到Ⅰ级水平，发展系数小于0．3，可用于该地区植物病虫害作中长期预测。     

Pervasive fungicide resistance in Botrytis from strawberry in Norway: Identification of the grey mould pathogen and mutations

Control of grey mould, caused by Botrytis spp., is a major challenge in open field strawberry production. Botrytis was isolated from plant parts collected from 19 perennial strawberry fields with suspected fungicide resistance in the Agder region of Norway in 2016. Resistance to boscalid, pyraclostrobin and fenhexamid was high and found in 89.1%, 86.0% and 65.4% of conidia samples, respectively. Multiple fungicide resistance was common; 69.6% of conidia samples exhibited resistance to three or more fungicides. Botrytis group S and B. cinerea sensu stricto isolates were obtained from 19 and 16 fields, respectively. The sdhB, cytb, erg27 and mrr1 genes of a selection of isolates were examined for the presence of mutations known to confer fungicide resistance to boscalid, pyraclostrobin, fenhexamid and pyrimethanil plus fludioxonil, respectively. Allele-specific PCR assays were developed for efficient detection of resistance-conferring mutations in cytb. Among B. cinerea isolates, 84.7%, 86.3% and 61.3% had resistance-conferring mutations in sdhB, cytb and erg27, respectively. A triplet deletion in mrr1, resulting in ΔL497, commonly associated with the multidrug resistance phenotype MDR1h, was detected in 29.2% of Botrytis group S isolates. High frequencies of resistance to several fungicides were also detected in Botrytis from both imported and domestically produced strawberry transplants. Fungicide resistance frequencies were not different among fields grouped by level of grey mould problem assessed by growers, indicating factors other than fungicide resistance contributed to control failure, a fact that has important implications for future management of grey mould.