The influence of some agricultural practices on soil organisms and plant establishment of sugar beet

In a long term field experiment the influence of crop rotation and the application of insecticides and herbicides on soil arthropods (mesofauna), nematodes, soil fungi and weeds was investigated. Possible changes in numbers of not only pathogenic organisms, but also of predators or parasites of pathogens, could affect seedling establishment and/or yield of sugar beet. In soil samples taken during the spring, high population of the springtailOnychiurus armatus ware detected which caused considerable damage in the first two years. Later also rather severe infestations byAtomaria linearis occurred, probably caused by frequent sugar beet cropping.No significant influence of crop rotation on damage caused by soil arthropods could be detected yet, but in the 1/3 sugar beet and 2/3 winter wheat rotation more micro-arthropods and a higher diversity of species were found than in the blocks with continuous sugar beet growing. In the latter ones the numbers ofHeterodera schachtii increased and in 1980 the tolerance level was exceeded. On the contrary in the 1/3 sugar beet blocksPratylenchus spp. were dominant. Since a number of perennial weeds cannot be controlled sufficiently in sugar beet, some of them created a problem in the 1/1 sugar beet blocks.In the plots not treated with a soil herbicide large numbers of annual weeds provided alternative native food forO. armatus, which resulted in less plant damage. No significant effect of chloridazon on the micro-arthropod fauna could be detected. The insecticides lindane and aldicarb controlledO. armatus andA. linearis partially, and improved seedling emergence and to a lesser extent yield. Both insecticides had a variable effect on the relative abundancy ofCollembola and in addition lindane suppressed numbers ofAcariformes and aldicarb those ofParasitiformes. No negative influence on the species diversity could be detected. All effects did not last long and varied considerably from year to year.Indications were found that, if species ofCollembola, which could act as predators of nematodes, were suppressed, the numbers ofPratylenchus spp. andH. schachtii increased.Samenvatting In een veeljarig proefveld (1976–1979) werd de invloed van de vruchtopvolging en toepassing van insecticiden en herbiciden op bodemarthropoden (mesofauna), nematoden, bodemschimmels en onkruiden onderzocht. Niet alleen mogelijke veranderingen in de aantallen schadeverwekkers, maar ook in de aantallen predatoren en pathogenen van bodemplagen zouden het plantbestand en/of de opbrengst van suikerbieten kunnen beïnvloeden.Gedurende de eerste twee jaar van de proef werden in grondmonsters, die gedurende het voorjaar werden genomen, grote aantallen springstaarten (Onychiurus armatus) aangetroffen, die aanzienlijke schade veroorzaakten. Later kwamen eveneens aantastingen door het bietekevertje (Atomaria linearis) voor, waardoor in meerdere of mindere mate planten wegvielen.Er kon nog geen duidelijke invloed van de vruchtopvolging op de schade door bodemarthropoden worden vastgesteld, maar in de rotatie met 1/3 suikerbieten en 2/3 wintertarwe werden meer micro-arthropoden en een grotere soortenrijkdom gevonden dan in de gedeelten met een continuteelt van suikerbieten. In laatstgenoemde veldjes zijn de aantallen bietecystenaaltjes (Heterodera schachtii) toegenomen, waarbij in 1980 de tolerantiegrens werd overschreden. Daarentegen vond in de veldjes met 1/3 suikerbieten in de rotatie een sterkere vermeerdering vanPratylenchus spp. plaats dan in de continuteelt. Aangezien een aantal wortelonkruiden in suikerbieten niet voldoende kan worden bestreden, veroorzaakten enkele na enige jaren een probleem in de continue bietenteelt.In de veldjes die niet met een bodemherbicide waren behandeld vormden grote aantallen zaadonkruiden een alternatieve voedselbron voorOnychiurus armatus, wat een geringere aantasting van kiemplanten tot gevolg had. Er werd geen aantoonbaar effect van chloridazon op de micro-arthropoden vastgesteld.De insecticiden lindaan en aldicarb konden schade doorOnychiurus armatus enAtomaria linearis slechts gedeeltelijk voorkomen; er werd een duidelijk betere opkomst en soms ook een hogere opbrengst verkregen. Beide insecticiden hadden een wisselende invloed op de relatieve talrijkheid vanCollembola en bovendien onderdrukte lindaan de aantallenAcariformes en aldicarb deParasitiformes. Er kon geen negatieve invloed op de soortenrijkdom worden vastgesteld. Al deze effecten waren niet van langdurige aard en verschilden sterk van jaar to jaar.Er werden aanwijzingen gevonden dat, indien bepaalde soortenCollembola, die als predatoren van nematoden kunnen optreden, werden onderdrukt, de aantallenPratylenchus spp. enHeterodera schachtii toenamen.     

The influence of the topographic position within highlands of Western Rwanda on the interactions between banana (Musa spp. AAA-EA), parasitic nematodes and soil factors

Soil properties vary according to the topography. They affect water uptake and root exploration in the soil. Consequently, they may also influence the spread of plant–parasitic nematodes. This study reports on the effect of toposequence-related variations in soil on banana yields, foliar nutrient status, and nematode impact. Twenty banana plots were visited within 6 hills/valleys at each of the three toposequence positions: valley bottom, mid-slope and crest. Important variability in plant growth, nutrition and soil properties was observed within the toposequence. Significantly better plant growth (height and girth) was observed in the valley bottoms, where banana bunch weight was 1.7–3.4 kg higher (although not significant) than at upper toposequence positions. Best plant growth was observed in valley bottoms in contrast to the highest N and K foliar deficiencies in this position. Plants in the valley bottoms had higher foliar Ca and Mg, and K compared to those in the crest. Plants in the mid-slope had greater percentage of dead roots (19.1%), compared to the plants in the valley bottoms (12.3%) and the crest (14.2%). Soils in the valley bottoms were deeper, sandier, with lower organic matter, lower N, and K compared to the soils at higher toposequence. Nematodes likely play a key role in banana root damage, however, their effect appear to be in relation to various soil factors at each position. The abundance of Pratylenchus goodeyi had generally limited impact on banana yields in fields having less than 5% slope (crest and valley bottom) where soil conditions were more optimal for root growth. However, in the presence of increased run-off on steeper middle slopes, root death was increased even under moderate pressure from P. goodeyi.     

1种苎麻根腐病线虫的鉴定

【目的】对分离的一种苎麻根腐病线虫进行形态和分子生物学鉴定,为病原线虫分子生物学检测技术的研发及苎麻根腐病的防治奠定基础。【方法】从感染苎麻根腐病植株根中分离出一种植物病原线虫,利用显微技术观察线虫的形态特征,对其进行初步鉴定;之后采用分子生物学技术,提取单条线虫的DNA,利用通用保守性引物扩增了线虫核糖体DNA内部转录间隔区(rDNA-ITS)序列,并用软件DNAstar和DNAMAN进行序列分析,对该植物病原线虫进行进一步鉴定。【结果】根据形态特征,将获得的苎麻根腐病线虫初步鉴定为咖啡短体线虫。序列分析结果表明,该线虫rDNA-ITS序列与咖啡短体线虫湖北种群、越南种群、台湾种群、日本种群及尼日利亚种群的同源性依次为99.8%,99.0%,98.0%,97.8%和94.6%。该线虫rDNA-ITS序列在GenBank注册号为HQ403649。【结论】形态及分子生物学鉴定结果表明,分离的苎麻根腐病线虫为咖啡短体线虫(Pratylenchus coffeae)。     

Efficacy of neem seed derivatives against nematodes affecting banana

Soil applications of powdered neem seed or neem cake at 100 g/plant at planting and, subsequently, at 3-month intervals, reduced the populations ofPratylenchus goodeyi Sher & Allen andMeloidogyne spp. on par with Furadan 5G (carbofuran) applied at 40 g/plant at planting and then at 6-month intervals to banana plants grown in 100-/ containers with controlled levels of banana nematode infestations. Eight months after planting, banana plants treated with powdered neem cake, seed or kernel or with neem oil had 4 to 95 times fewer parasitic nematodes than the untreated control. However, only neem cake powder or neem seed powder applied to unpared banana plants kept the nematode population below the economic threshold.     

杜仲林咖啡豹蠹蛾发生及防治建议

本研究对咖啡豹蠹蛾的生物学特性进行了观察,调查了对杜仲的危害情况,并对该虫的防治进行了初步探讨     

茶木蠹蛾生活习性及有效积温

茶木蠹蛾ＺｅｕｚｅｒａｃｏｆｆｅａｅＮｉｅｔｎｅｒ是茶树的主要枝干害虫之一,尤其是新辟茶园被害严重。在安徽省一年１代,以老熟幼虫越冬,幼虫期为５龄,危害期长达１２０—１５０ｄ,一生中可转移钻蛀５—１０个枝干。经变温测定：蛹期发育起点温度Ｃ＝（１５．０±０．７）℃,有效积温Ｋ＝（１７４±１２）ＤＤ,预测式Ｎ＝（１７４±１２）／〔Ｔ－（１５．０±０．７）〕（ｄ）,卵期发育起点温度Ｃ＝（１７．６±０．８）℃,有效积温Ｋ＝（１２４±７）ＤＤ,预测式Ｎ＝（１２４±７）／〔Ｔ－（１７．６±０．８）〕（ｄ）。     

云南石榴根际刻痕短体线虫的鉴定

近年来云南石榴病害日趋严重,特别是根部病害,因为其危害具有隐蔽性,常被人们忽略,线虫病害即其中之一.2003-2007年,笔者对云南省主要石榴产区蒙自县、会泽县和建水县的石榴寄生线虫进行了采样调查,采用形态特征进行鉴定,分离鉴定出了刻痕短体线虫.报道了寄生于云南省石榴根际的一种短体线虫:刻痕短体线虫Pratylenchus crenatus,Loof 1960,石榴是这种线虫的新记录寄主.     

石榴豹纹木蠹蛾(Zeuzera coffeae Nietner)生物学及其防治研究

石榴豹纹木蠹蛾是云南蒙自地区石榴的主要害虫之一。幼虫蛀害石榴树枝干 ,具多次转移危害习性 ,并在蛀道内越冬。受害部位以上枝干萎蔫、枯死 ,危害枝干率达 1 0 %～ 1 5 % ,重者达 30 %～ 40 %。该虫在云南蒙自石榴植区一年发生一代 ,垮年度完成 ,越冬态不甚明显。采取综合防治措施后 ,其危害率由 1 0 %～ 1 5 %降为 0 .2 %～ 0 .31 %。     

无花果主要寄生线虫在江苏主产区的分布与季节性消长动态

１９９１～１９９３年对江苏南京、句容、如东、海门、泗洪和宿迁６个无花果种植区无花果寄生线虫的种类和发生进行了调查。从采集的１１２份土样、７１份根样中共发现５属４种寄生线虫。其中,南方根结线虫和咖啡短体线虫较常见,田间群体密度也较高,是无花果的主要致病线虫。对这两种线虫密度的季节动态调查表明,线虫的发生在５～６月和１０～１１月份都呈现明显的高峰,且与无花果的２次新根发生期和温度的季节变化规律密切相关。