Triaenophorus nodulosus and T. crassus in fish from northern Finland

10,288 fish specimens of 34 species from three water bodies in northern Finland were studied mainly in 1978-1982 Triaenophorus nodulosus and T. crassus parasites. Six of the 31 species from the Bothnian Bay were found to harbour T. nodulosus plerocercoids, four of the 11 from the cold, oligotrophic Lake Yli-Kitka in northeastern Finland and only one of the 6 from the small, eutrophic Lake Kuivasj?rvi. The ruff (Gymnocephalus cernuus) was most essential intermediate host in the lakes, as supported by stomach analysis of predator fish. Although the highest prevalences were found in adult burbot (Lota lota) in two of the areas, these fish are more likely a blind end in the life cycle of T. nodulosus in the present case. T. crassus larvae were found only in three coregonid species and once in the intestine of a lamprey (Lampetra fluviatilis) from the sea. Neither the prevalence nor the intensity of infection in most of the intermediate fish hosts of T. nodulosus was seen to increase with the length of the fish. The only exception was the ruff in Lake Yli-Kitka, where a sharp increase was encountered. No prominent seasonal variation in Triaenophorus larvae infections was found in any of the cases. The prevalence of T. nodulosus infection in its final host, the pike (Esox lucius), was highest in the sea (93%) and lowest in the eutrophic lake (47%). Seasonally, the lowest T. nodulosus infections were found in June-July in the two lakes. A clear maturation cycle was also found, with the youngest worms in the summer months in all cases. T. crassus was found in every third pike in the sea and its proportion in relation to T. nodulosus is higher in the smallest and largest fish. In only 12%t of the pikes did the number of T. crassus exceed that of T. nodulosus, however, the mean ratio being 1:13 to favour of T. nodulosus. The results give an indication that the composition of the fish fauna in each water body has a considerable influence on the T. nodulosus burden and its distribution among its potential intermediate fish hosts. With the most stable environmental conditions and the greatest variety of fish species, the parasite burden in the Bothnian Bay is most evenly distributed among the 6 intermediate hosts. The fewer fish species occur in the water body, as in the present eutrophic lake, the more the significance of a few or even one intermediate host will increase.     

Occurrence and Pathogenicity of Fusarium Species in Cereals in Finland1

Several Fusarium species occurred abundantly in spring cereal seed samples studied in 1966, 1968 and 1972 in Finland. A total of 17 species of Fusarium were isolated and identified. The most frequently isolated species were F. avenaceum (Fr.) Sacc., F. culmorum (W. G. Sm.) Sacc., F. poae (Peck) Wr. and F. tricinctum (Cda) Sacc. These species were found in more than 40% of the seed samples from 1972. The same 4 Fusarium species in addition to F. graminearum Schwabe were used in the pathogenicity test. Artificially inoculated spring wheat and barley seeds were grown in the field during the growing season of 1973. Of these 5 species F. culmorum was clearly the most pathogenic. This species significantly lowered the shooting percentage and the yield of both cereals. Foot rot assessment also revealed F. culmorum as the most damaging species. Natural soil-borne infection obviously increased the foot and root rot, and thus the soil-borne F. culmorum strongly affected all treatments. In the harvested seed F. poae dominated in all treatments, but F. culmorum still occurred most abundantly in the seed lot harvested from plots originally inoculated with this species.     

赣北地区柿绒蚧发生规律及防治技术

本文简述了柿绒蚧在赣北地区柿园为害特点与发生规律，并提出了防治措施。     

菊花白锈病发生规律与药剂防治

菊花白锈病于 1997年传入山东潍坊地区 ,危害严重。笔者经近 3年的调查研究 ,基本明确了该病在当地发生规律 ,并筛选出对其有效的药剂 10 %世高水分散粒剂和 40 %福星乳油。     

Occurrence and distribution of viruses infecting tomato and pepper in Alibori in northern Benin

In surveys conducted in 2011 and 2012 to identify the viruses causing diseases on pepper and tomato in the department of Alibori in northern Benin, 451 samples of pepper and tomato were analyzed by ELISA using 11 specific antibodies. The highest virus incidence among the surveyed districts was recorded on pepper in Malanville (56.18%), followed by Karimama (39.32%). The most frequently found viruses were Pepper veinal mottle virus (PVMV), Cucumber mosaic virus (CMV), and Potato virus Y-necrotic (PVY-n), accounting respectively for 22.39%, 21.73% and 15.96% of the collected samples. Tomato yellow leaf curl virus (TYLCV) was detected in only 2.43% of the samples, whereas Alfalfa mosaic virus (AMV), Chilli veinal mottle virus (ChiVMV), Tomato mosaic virus (ToMV) and Tomato spotted wilt virus (TSWV) were not detected in any of the samples tested. Double and triple infections involving different virus combinations were found, respectively, in 14.86% and 4% of the samples. Five plant species (Euphorbia hirta Linnaeus, Moringa oleifera Lam, Leucas martinicencis (Jacquin) R. Brown, Combretum micranthum G. Don, Abelmoschus esculentus L. Moench.) out of 30 samples belonging to 13 botanical families, collected within or nearby tomato and pepper fields, were found infected with PVMV, PVY-n, and CMV. Control measures to reduce the impact of viruses on pepper and tomato production are discussed. This is the first report of viruses infecting pepper and tomato in Benin.     

我国北方部分苹果主产区病毒病的发生与检测

苹果病毒病在我国广泛发生,已成为限制我国苹果优质高产的关键因素。20世纪80年代曾对其做过详细的调查和研究,但近年来由于各地农业产业结构调整等因素,苹果病毒病的发生特点有了不同程度的变化。为了解目前我国苹果病毒病的发生情况,在我国北方苹果主产区山东、陕西、山西、辽宁、北京和黑龙江6个省市的部分地区采集苹果样品共计267份,经RT-PCR检测和扩增产物的克隆与测序分析表明在上述地区采集的样品中,苹果褪绿叶斑病毒(ACLSV)、苹果茎沟病毒(ASGV)、苹果茎痘病毒(ASPV)、苹果锈果类病毒(ASSVd)的发生率分别为66.7%~100.0%、38.1%~94.1%、4.8%~85.7%和4.8%~48.6%;苹果凹果类病毒(ADFVd)仅在山东的两个果园零星发生;6个省市样品中病毒复合侵染率分别为67.1%、92.1%、75.0%、88.2%、94.1%和76.2%。     

安徽北部小麦田草地贪夜蛾发生情况及田间防治试验

2019年11月9日至15日对安徽北部小麦田草地贪夜蛾发生情况进行了调查,发现涡阳县、蒙城县、利辛县、谯城区、临泉县等地部分田块为害偏重,每平方米最高虫量达51头,百株被害率最高为66.85%。利用C OⅠ和Tpi基因进行遗传分析,发现采自涡阳小麦田的试虫均为玉米型。田间防治试验结果表明,10%甲维盐·氯虫苯甲酰胺悬浮剂和12%甲维盐·虫螨腈悬浮剂药后3 d防效分别为90.64%和92.17%;药后14 d防效分别为91.32%和92.26%,速效性和持效性皆较佳,可作为防治小麦田草地贪夜蛾的推荐药剂。     

北方稻区水稻害虫发生与防治

北方稻区,特别是东北早熟单季稻稻区,水稻种植面积逐年扩大,随着全球气候变暖和耕作栽培制度等因素的变化,其水稻害虫发生面积和危害程度逐渐增大,对北方优质水稻生产构成了较大影响。本文综述近年来北方稻区水稻害虫发生危害概况,分析引起害虫发生危害的原因,总结区域性的水稻害虫防治策略和技术。     

草地贪夜蛾在江苏北部早播麦田的发生与防治

草地贪夜蛾Spodoptera frugiperda(J.E.Smith)是我国重要的外来入侵害虫,2019年8月22日于江苏北部东辛农场发现草地贪夜蛾为害玉米,9月26日水稻田间零星见虫,10月22日在早播小麦上初次发现草地贪夜蛾造成危害,小麦被害率达52.60%,百株虫量20.4头。进一步研究发现5.7%甲维盐WG防治草地贪夜蛾药后7 d防效达96.45%,表现较好,可用于麦田草地贪夜蛾的防治。根据当前草地贪夜蛾为害小麦的严峻形势,我们必须加强对麦田草地贪夜蛾的监测与防控。     

滨州市冬枣锈病发生特点与综合治理

冬枣产于山东省渤海地区、黄河三角洲腹地，是一种成熟期较晚，珍贵稀有的鲜食果品。滨州市冬枣种植面积达6万hm^2，已成为当地农业经济新的增长点和农民致富奔小康的主导产业。但是冬枣锈病2004年在滨州市暴发流行，给枣农的增收和冬枣产业的发展造成了极大的创伤。为此对冬枣锈病流行规律、流行原因和治理对策进行了调研。     

Occurrence of Phyllodistomum umblae (Fabricius, 1780) in the ureters of coregonids of Lake Yli-Kitka in northeastern Finland

380 whitefish (Coregonus sp.) and 260 vendace (Coregonus albula L.) were studied from Lake Yli-Kitka in northeastern Finland during 1980-1982. 33% of the whitefish and 38.5% of the vendace were infected with Phyllodistomum umblae (Fabricius, 1780), the average intensity of infection being 4.2 and 2.3 per infected fish, respectively. No clear seasonality was observed in either the prevalence and intensity of infection or in the level of maturation and the length of P. umblae in both fish species, which points to a continuous invasion and maturation of these trematodes. The prevalence and intensity of P. umblae infection was highest in the middle-sized whitefish. Similar results were obtained when the mean number of worms per fish and the level of overdispersion (S2/x) are plotted against the length of the fish. With regard to vendace the prevalence and intensity of infection per infected fish and per fish studied increased as the fish length increased: only the variance-to-mean ratio remained constantly low. Overdispersion indices (S2/x) revealed that in the whitefish P. umblae is more overdispersed than in vendace when studied using data from seasonal periods with size-groups as homogenously infected as possible. The negative binomial distribution gave a good fit in the case of vendace and with one exception also for whitefish, and the values of parameter k are well within the limits most often found in parasitological studies.     

Biological diversity of Rhizoctonia solani (AG-3) in a northern potato-cultivation environment in Finland

A total of 119 isolates of Rhizoctonia were collected from stem canker lesions, stolon and root lesions, hymenia on stems, or from black scurf on tubers of potato plants ( Solanum tuberosum ) in Finland (latitudes 60–67°N). All isolates except three belonged to anastomosis group 3 (AG-3) of R. solani , as determined by phylogenetic analysis of the internal transcribed spacer sequences (ITS1 and ITS2) of ribosomal RNA (rRNA) genes. Sensitivity of the 119 isolates to the fungicide flutolanil was tested in vitro (EC₅₀ values 0·14–0·75  µ g active ingredient mL⁻¹). The isolates also varied considerably in growth rate (5·1–14·8 mm day⁻¹). The severity of disease caused by 99 isolates was determined based on the proportion of potato sprouts affected by lesions, discoloration or death, which was c . 1–60%. Only two isolates that were able to cause severe symptoms showed particularly low sensitivity to the fungicide and rapid growth rate. One isolate each of anastomosis groups AG-2-1 and AG-5 and an unknown, binucleate Rhizoctonia sp. were detected. The AG-5 isolate and the binucleate isolate caused mild symptoms on potato sprouts, whereas the AG-2-1 isolate was not pathogenic. Taken together, AG-3 of R. solani was the predominant causal agent of the stem canker and black scurf diseases of potato in Finland and showed considerable variability in disease severity, fungicide sensitivity and growth rate in vitro .     

Variability of Peronospora Sparsa (syn. P. rubi) in Finland as Measured by Amplified Fragment Length Polymorphism

Downy mildew caused by Peronospora sparsa (syn. P. rubi) is a serious threat to commercial cultivation of arctic bramble (Rubus arcticus subsp. arcticus) in Finland. P. sparsa is distributed throughout the country in cultivated and wild arctic bramble and in cloudberry (R. chamaemorus). A total of 36 isolates of P. sparsa collected from these hosts was analysed for amplified fragment length polymorphism (AFLP). Of the 226 markers scored, 223 were polymorphic and all isolates of P. sparsa had unique AFLP fingerprints, which indicated high levels of genetic variability. An UPGMA clustering analysis of the isolates did not reveal any genetically distinguishable strains. The isolates were grouped neither according to the geographic origin nor the host from which they were isolated. Isolates of P. sparsa obtained from wild arctic bramble and one from cloudberry readily infected the leaves of the cultivated arctic bramble (cultivar Pima). Also, P. sparsa isolated from cultivated arctic bramble infected the leaves of wild arctic bramble. These data suggest that P. sparsa may be disseminated from wild arctic bramble and cloudberry to cultivated arctic bramble in the field.     

蓟马严重危害温室杜鹃花及其防治技术

花卉产业是咸阳地区大力发展的新兴产业,对提高人民生活质量,美化市容和居家环境,增加农民收入,发展外向型农业有着广阔的前景.咸阳市先后引入了十多家花卉苗木公司,其中,冠杰园艺公司温室栽培的比利时杜鹃花面积达 2.67 hm2,栽培比利时杜鹃40万盆以上,年创产值400万元以上.但2004年7～10月,该花受蓟马危害严重,单花平均有虫7～10头,最高为20～30头,造成花蕾受害干枯不开放,花瓣扭曲变形焦枯.每个温室平均危害率70%以上,严重的达100%,杜鹃花完全丧失观赏性及商品价值,直接经济损失100万元以上.     

Occurrence of Blastocystis sp. in pigs

The occurrence of Blastocystis sp. was monitored in pigs of various age from 5 pig farms in Southern Bohemia. Prevalence was determined especially via cultivation in modified nutrient broth LES. In sucking pigs up to 2 days old Blastocystis sp. was not found; from 3 days Blastocystis sp. persists throughout the pig life. In droppings and in cultures there both vacuolar and granular forms were observed. Ameboid forms were not found. In culture ultrastructure was observed by transmission electron microscopy. Individual cells of Blastocystis sp. contained a central body, nucleus, endoplasmic reticulum, rarely a Golgi complex and numerous mitochondria. No essential differences from known ultrastructure of human Blastocystis hominis were found.     

Survey for Phytophthora fragariae var. fragariae in Finland

A survey for the possible occurrence of red-core disease ( Phytophthora fragariae var. fragariae ) was carried out on 250 strawberry production sites in Finland. The fields were inspected visually. A total of 1080 samples of strawberry roots were taken in spring and autumn 1995 and examined visually, microscopically and by isolation in the laboratory. Root-tip bait-plant tests were performed in the glasshouse to look for the latent presence of the fungus. No red-core disease was detected in any of the inspected fields or in the examined samples.     

Ultrastructure of the apical glandular region of the scolex of Proteocephalus torulosus (Cestoda: Proteocephalidae)

In the apical glandular region of the adult Proteocephalus torulosus (Batsch, 1786), two types of eccrine gland cells are present. The first type of unicellular gland produces large electron-dense granules of various sizes. The second type contains small electron-dense granules. Most cells form glands with large granules; glands with small granules are infrequent. The secretion of both types of gland cells is concentrated in the apical parts of the cyton and in the ducts opening to the exterior. On the scolex of P. torulosus, there are regional structural differences of the microthrix border. The apical glandular region bears filamentous microtriches only. On the remaining frontal part, surrounding the glandular region, there are blade-like and filamentous microtriches. The lateral parts of the scolex and suckers bear blade-like microtriches. Possible functions of both types of gland cells and different parts of the scolex microthrix border are discussed. The unique structure of the frontal part of the scolex of P. torulosus and its differences from Proteocephalus macrocephalus, P. longicollis and P. percae correlate well with the putative basal phylogenetic position of P. torulosus among European species of Proteocephalus.     

山西冬麦穗夜蛾发生规律及综合防治

冬麦穗夜蛾是山西中、南部丘陵旱塬地区麦田的一种新害虫，80年代以来为害日趋严重，一般损失5％～10％，较重的达30％以上。为控制其为害作者从1991年对该虫的发生规律、防治途径进行了研究。综合防治以机械收脱、深耕、火烧麦茬、低留茬；用40％氧乐果、25％菊乐合剂、40％水胺硫磷1500倍进行防治，均能取得良好的防治效果。     

花椒波瘿蚊寄生蜂——广肩小蜂田间发生规律研究

广肩小蜂Eurytoma sp.是花椒波瘿蚊Asphondylia zanthoxyli bu & Zheng的重要寄生天敌.广肩小蜂1年发生3代,以蛹在花椒波瘿蚊为害形成的虫瘿内越冬.第2年花椒发芽后在4月中旬越冬代成虫羽化;第1代成虫6月上旬羽化;第2代成虫8月上旬羽化.成虫产卵于花椒波瘿蚊幼虫为害后形成的虫瘿内;孵化后外寄生于花椒波瘿蚊幼虫,将寄主幼虫吃光后化蛹.越冬代寄生率达48.39%,第2年花椒发芽前剪除虫瘿枝可有效保护广肩小蜂种群数量.     

Simultaneous detection by multiplex PCR of the high-temperature-growing Pythium species: P. aphanidermatum, P. helicoides and P. myriotylum

The objective of this study was to develop a multiplex PCR detection method for the high-temperature-growing pathogens Pythium aphanidermatum, P. helicoides and P. myriotylum. Species-specific primer pairs were designed that targeted the rDNA ITS regions. The multiplex PCR was constructed with a universal primer pair for eukaryotes directed at the 18S rDNA as a positive control, in addition to the three species-specific primer pairs. When the multiplex PCR was applied to naturally infested soils, the expected species were reliably identified, suggesting that the method is suitable for the detection of the three Pythium pathogens in environmental samples.