Monitoring conidial density of <Emphasis Type="Italic">Monilinia fructigena</Emphasis> in the air in relation to brown rot development in integrated and organic apple orchards

In a three-year Hungarian study, conidial density of Monilinia fructigena in the air determined from mid-May until harvest was related to brown rot disease progress in integrated and organic apple orchards. Conidia of M. fructigena were first trapped in late May in both orchards in all years. Number of conidial density greatly increased after the appearance of first infected fruit, from early July in the organic and from early August in the integrated orchard. Conidial number continuously increased until harvest in both orchards. Final brown rot incidence reached 4.3–6.6% and 19.8–24.5% in the integrated and organic orchards, respectively. Disease incidence showed a significant relationship with corresponding cumulative numbers of trapped conidia both in integrated and organic orchards, and was described by separate three-parameter Gompertz functions for the two orchards. Time series analyses, using autoregressive integrated moving average (ARIMA) models, revealed that the temporal patterns of the number of airborne conidia was similar in all years in both integrated and organic orchards. Conidia caught over a 24-h period showed distinct diurnal periodicity, with peak spore density occurring in the afternoon between 13.00 and 18.00. Percent viability of M. fructigena conidia ranged from 48.8 to 70.1% with lower viability in dry compared to wet days in both orchards and all years. Temperature and relative humidity correlated best with mean hourly conidial catches in both integrated and organic apple orchards in each year. Correlations between aerial spore density and wind speed were significant only in the organic orchard over the 3-year period. Mean hourly rainfall was negatively but poorly correlated with mean hourly conidial catches. Results were compared and discussed with previous observations.     

Effect of prior tillage and soil fertility amendments on dispersal of Phytophthora capsici and infection of pepper

Organic soil amendments including composted cotton gin trash, composted poultry manure, an incorporated rye-vetch green manure, or synthetic fertilizer were applied to subplots, and main plots were either tilled frequently or surface-mulched in experimental field plots between 1997 and 2004. Soil from each replication of the tillage and fertility treatments was sampled in August of 2001, 2002, and 2003, brought to the greenhouse, and infested with Phytophthora capsici to study the effect of previous soil treatments on disease incidence and dispersal of the pathogen. Both the previous tillage and fertility amendments affected the incidence of disease and dispersal of the pathogen. Final disease incidence, AUDPC and the distance of pathogen spread were significantly greater in soils with previous surface mulch applications than in frequently tilled soils. Final disease incidence, AUDPC and the distance of pathogen spread were also significantly higher in soils amended with cotton gin trash, than rye-vetch green manure, poultry manure, or synthetic fertilizer. Soils amended with cotton gin trash had higher soil water content, lower bulk density, higher humic matter content, higher porosity and higher levels of mineralizable N, than soils with other fertility amendments. Soil water content, soil porosity, humic matter content, and net mineralizable levels nitrogen were positively correlated and bulk density was negatively correlated with final incidence of disease.     

Activity of carboxylic acid amide (CAA) fungicides against Bremia lactucae

Four carboxylic acid amide (CAA) fungicides, mandipropamid (MPD), dimethomorph (DMM), benthiavalicarb (BENT) and iprovalicarb (IPRO) were examined for their effects on various developmental stages of Bremia lactucae, the causal agent of downy mildew in lettuce, in vitro and in planta. Spore germination in vitro or on leaf surfaces was inhibited by all CAA fungicides (technical or formulated). MPD was more effective in suppressing germination than DMM or BENT, whereas IPRO was least effective. CAA induced no disruption of F-actin microfilament organisation in germinating spores of B. lactucae. CAA applied to germinating spores in vitro prevented further extension of the germ tubes. When applied to germinated spores on the leaf surface they prevented penetration. Preventive application of CAA to intact plants inhibited infection. MPD was more effective in suppressing infection than DMM or BENT, whereas IPRO was least effective. Curative application was effective at ≤3 h post-inoculation (hpi) but not at ≥18 hpi. CAA (except IPRO) applied to upper leaf surfaces inhibited spore germination on the lower surface and hence reduced infection. CAA suppressed sporulation of B. lactucae on floating leaf discs and when sprayed onto infected plants two days before onset of sporulation. BENT and DMM were more effective in suppressing sporulation than MPD or IPRO. Epidemics of downy mildew in shade-house grown lettuce were suppressed by CAA. A single spray applied to five-leaf plants before transplanting controlled the disease for 50 days. The results suggest that CAA are effective inhibitors of spore germination and therefore should be used as preventive agents against downy mildew of lettuce caused by B. lactucae.     

Suppression of Fusarium wilt of spinach with compost amendments

The effect of different organic composts on the suppression of wilt disease of spinach caused by Fusarium oxysporum f. sp. spinaciae was evaluated in a continuous cropping system in both containers and in microplot field trials. Test soils infested with the pathogen were amended with wheatbran, wheatbran and sawdust, coffee grounds, chicken manure, or mixture of different composts with and without 5% (w/w) crab shell powder either once (5%, w/w) or continuously (2.5%) into the test soils infested with the pathogen. In the container trials, the soil amended with composts became suppressive to disease development on the second and third cropping. The suppressive effect was notable in the soil amended with the mixture of compost with and without crab shell powder. The coffee compost lowered soil pH but became suppressive to the disease after modifying the soil pH. In the field trial using the mixture of the different composts containing 5% crab shell powder, a combination of 5% before the first cropping and 2.5% every second cropping gave stable disease control and promoted plant growth. After compost amendment, populations of fungi, bacteria and actinomycetes as measured by dilution plate counting and the total microbial activity as evaluated by fluorescein diacetate hydrolysis increased and population of the pathogen gradually decreased. These phenomena were especially notable in soils amended with the mixture of different composts. These results indicate that diversity in the organic materials promotes higher microbial activity and population in the soil thereby enhancing disease suppressiveness.     

菜用大豆新品种‘青酥五号'的选育

‘青酥五号'是以‘AVR-1'为母本、‘VS-9'为父本,经有性杂交后连续8代自交系统筛选,育成的菜用大豆新品种。该品种全生育期约84 d,株型直立,有限结荚;鲜荚淡绿色,标准荚长×荚宽为5.33 cm×1.33 cm,每500g标准荚数196个,鲜荚产量9 t/hm~2以上,比对照‘青酥二号'增产27.8%;鲜豆百粒重达77.65 g,白花,灰毛,鲜籽粒易烧煮。     

浅谈矮牵牛的习性、繁殖及栽培管理

矮牵牛(Petunia hybrida Vilm)又名碧冬茄,是多年生草本植物,原产于南美,于19世纪初在欧洲用一些原产于南美的野生种杂交选育而成。喜温暖和阳光充足的环境。不耐霜冻,怕雨涝。     

不同生态装备对中华鳖稚鳖生长·抗病力和品质的影响

[目的]研究装置池塘生态装置下中华鳖稚鳖生长、抗病力与品质的关系。[方法]试验组4口培育池设置人工隐蔽物、网片晒被台、配置微流水装备、循环水生物净化系统、纳米微孔增氧系统、光照增加系统、温度调控系统等生态装备,对照组（CK）3口培育池,无以上生态装备。[结果]试验组培育池稚鳖的育成平均体重、绝对增重率、瞬时增重率、成活率、伤残率与CK差异极显著（P〈0.01）,分别较对照池高31.1%、33.5%、9.3%、12.8%及低7.2倍。[结论]试验池育成的稚鳖体貌品质明显优于CK。     

基于SVM二叉树的猪呼吸系统疾病诊断方法的研究

[目的]研究一种基于SVM二叉树的猪呼吸系统疾病诊断方法。[方法]首先利用聚类思想,定义了一种基于疾病特征权重的分离程度;每次将分离程度最大的类分离出来,得到了累积误差更小的决策树;并将二叉树SVM用于常见的4种呼吸系统疾病的诊断试验。[结果]该方法可行,可用于猪呼吸系统疾病的早期诊断。[结论]该研究为促进我国猪养殖业的健康发展及农民增收提供了参考。     

不同结构日光温室温湿度变化规律及其对番茄产量和病害的影响

选取山东Ⅲ型、Ⅳ型、Ⅴ型3种结构类型的日光温室,利用温室记录控制系统采集温室内的温湿度变化数据,并调查供试作物番茄产量和病害发生情况。结果表明,山东Ⅳ型日光温室保温、除湿效果优于山东Ⅲ型、Ⅴ型,且较适合种植番茄,产量高,病害轻;3种不同构型温室的番茄产量均与温度呈显著正相关,山东Ⅳ型和Ⅲ型温室的番茄产量与湿度间的相关性达到5%显著性水平,山东Ⅴ型温室的番茄产量与湿度的相关性达到1%显著水平。     

不同药剂对甘薯疮痂病的防控效果

为有效防控甘薯疮痂病,试用甲基托布津可湿性粉剂、多菌灵可湿性粉剂、苯菌灵可湿性粉剂、代森锰锌可湿性粉剂、硫酸链霉素可溶性粉剂、噻菌铜悬浮剂和硫磺?多菌灵悬浮剂7种药剂对甘薯疮痂病的防控效果进行对比试验。结果表明,50%硫磺?多菌灵悬浮剂500倍液、50%多菌灵可湿性粉剂400倍液和70%甲基托布津可湿性粉剂600倍液对甘薯疮痂病的防控效果较好。