黑龙江省大豆孢囊线虫研究进展

黑龙江省大豆孢囊线虫研究进展黑龙江省农业科学院大豆研究所于佰双大豆孢囊线虫（Ｈｅｔｅｒｏｄｅｒａｇｌｙｃｉｎｅｓ，ＳＣＮ）是大豆生产上的主要病害之一。我国自８０年代初期开始重视对该病的研究。黑龙江省农科院刘汉起等１９７６年调查表明，在黑龙江省除边远县...     

美国向大豆孢囊线虫宣战

针对近年来对大豆孢囊线虫在美国大豆主产州危害日趋严重却防治不利的趋势，美国大豆协会发起并组成了“防治大豆孢囊线虫联盟”，提出了“检测上壤，消灭孢囊线虫”的口号，大力宣传普及孢囊线虫危害及防治技术知识。该组织提出的防治SCN的综合措施为：①土壤检测；②选用抗病品种；③合理轮作；④栽培措施；⑤清洁措施；⑥施用杀线虫剂。     

八五三农场大豆孢囊线虫发生情况调查与防治技术

通过1989－1991年对大豆孢囊线虫着根量与土壤隐囊线虫普查及1998－1999年大田土壤孢囊线虫抽查，结果表明：八五三农场大豆孢囊线虫的发生非常普遍，危害了十分严重，10年间土壤中有孢囊地块由原来的50％上升到100％，迫切需要采取综合措施有效地对孢囊虫进行防治。     

土壤真菌防治大豆孢囊线虫的效果测定

在室内水洋菜平板上测定从山东胶县大豆孢囊线虫卵中分离到的草酸青霉菌Peni—cillium oxalicum Currie ＆ Thom、枝顶孢霉菌Acremonium persicinum(Nic—ot)W.Gams、地霉菌Geotrichum sp.、茄病镰刀菌Fusarium solani(Mart.)Sacc和尖孢镰刀菌F、oxysporum Schlecht在大豆孢囊线虫卵上的寄生率,分别为43％、28％、21％、29％和37％。盆钵实验结果表明,5％的草酸青霉菌和茄病镰刀菌菌剂防治大豆孢囊线虫的效果分别为72％和70％,前者1％的菌剂用量即有明显防效。这2种真菌是大豆的非病原菌。     

蓖麻对大豆孢囊线虫的影响

蓖麻对大豆孢囊线虫的影响黑龙江省农科院植保所王克勤大豆孢囊线虫是大豆的重要病害之一，尤其在我国北方大豆产区发生普遍，危害严重。造成了大豆产量和品质的下降，有的地方甚至绝产。目前主要采用轮作，药剂和抗病品种等防治措施。非寄主植物与大豆孢囊线虫的关系有人...     

大豆抗孢囊线虫基础研究

本文从大豆－大豆孢囊线虫相互关系、大豆抗性的生化基础和遗传本质三个方面对大豆抗孢囊线虫的基础研究作了简要概述。     

稳定大豆孢囊线虫群体变异的对策

稳定大豆孢囊线虫群体变异的对策黑龙江省农业科学院大豆研究所薛庆喜，姚远大豆孢囊线虫是一种两性繁殖的二倍体（２ｎ＝１８）生物。通过本身群体的寄生性基因进行遗传重组而寄生在寄主上。大豆孢囊线虫有着广泛的寄主，国外报道这种线虫的寄主植物有１７０多种，但主要...     

长期轮作和连作对土壤中 大豆胞囊线虫数量的影响

在白浆土设计长期轮作和连作试验区,采取麦麦豆油玉豆6区轮作和麦玉豆连作, 18a内连续调查土壤 中大豆胞囊线虫( SCN)的胞囊数量,观察轮作或连作对土壤中SCN胞囊数量的影响。试验结果表明,长期轮作使 土壤中胞囊数量有减少的趋势,各茬口间胞囊数量变化幅度减小,轮作12a后土壤中胞囊数量达到动态平衡;大豆 连作的前2a土壤中胞囊数量急速增加,以后缓慢增加, 7a后有下降趋势, 14a后土壤中的胞囊数量在较高水平上趋 于平衡;小麦或玉米连作前3a土壤中的胞囊数量呈快速下降, 4a后缓慢减少, 14a后土壤中胞囊数量极少。     

The production of dihaploids and tetraploids with combined quantitative resistance to potato cyst nematode (Globodera pallida) and foliage blight (Phytophthora infestans)

Summary Dihaploids were produced from tetraploids which had resistance to foliage late blight (P. infestans) and had a range of levels of resistance to white potato cyst nematode (PCN) (G. pallida). Twelve of 33 dihaploids tested had useful levels of both resistances, 11 were resistant to blight alone and seven to PCN alone. There were no significant correlations between the resistances of the parents and the mean resistance of their dihaploids, for either character. There was also no correlation between levels of resistance to blight and to PCN. There were significant differences in mean levels of resistance to blight and to PCN between the tetraploid progenies of two dihaploids which possessed combined resistance.     

Relationship between potato cyst nematodes and their principal host. IV. Tolerance of potato cultivars and the effect of potato cyst nematode on initial plant growth

Summary Greenhouse experiments on the effects of white potato cyst nematode infestations (Globodera pallida Stone) on initial growth and development of a series of potato cultivars are compared with the results of field experiments on sandy and sandy-peat soils on the effect of nematode density on tuber yield. A simple greenhouse test, assessing root growth response to potato cyst nematode infection, provided a good insight into a cultivar's tolerance performance in the field early in the growing season. As a very limited number of plants is needed for the greenhouse test, screening for tolerance can be conducted in the early stages of a breeding programme.     

The effect of leaf shape on the deposition of spray droplets in rice

Paddy rice is usually sprayed with different types of conventional hydraulic nozzles and application rates. Spray droplets are more easily captured by the tip of rice leaves; this phenomenon was therefore studied with rice plants in a settling tower so that deposition of droplets occurred under controlled conditions. Further tests were carried out in rice fields by dirferent methods. The deposition rate was generally higher at the leaf tip compared with other parts, whether the leaf was vertical, pointing downwards at an angle of 60 degrees, horizontal or in a normal position. Similar results could be obtained if leaf-like water-sensitive paper strips were used instead of a natural rice leaf. The deposition and distribution pattern found on field rice leaves confirmed these results. Deposits on water-sensitive papers of different widths (2–25 mm) showed fewer droplets as the target width increased.     

The use of liquid swine manure for the control of potato cyst nematode through soil disinfestation in laboratory conditions

In this laboratory study the effect of liquid swine manure (LSM) on Globodera rostochiensis was evaluated. The LSM was applied to 500 g nematode-infested soil at 0.4, 2.0, 4.0, and 6.0% (v/w), equivalent to 31, 155, 310 and 465 kg of N ha⁻¹, in closed and open containers (microcosms sealed (S) and open (O)). The results showed that LSM in closed containers enriched the volatile fatty acids (VFAs) through partial anaerobic incubation process. Bacterial- and fungal-feeding nematodes predominated, while the least opportunistic groups had a very low occurrence. The LSM in (S) significantly decreased cyst nematode populations and percent egg hatching in contrast with opened ones (O), increasing some chemical parameters related to soil fertility. Hatching tests showed that individual VFA vary in their lethality to G. rostochiensis. Acetic and propionic acids were the most toxic, reducing hatching most effectively and irreversibly. Results suggest that soil disinfestation on laboratory tests with LSM, is an efficient way for the reduction of G. rostochiensis populations in acidic soils, due to the VFAs nematicidal action. To address management alternatives, field studies would be needed that compared these materials to the current management practices, and demonstrated that they are competitive in the field.     

Observations on the prevalence and incidence of cereal cyst nematode (Heterodera avenae) in Scotland

A survey of the incidence of cereal cyst nematode (CCN) in Scottish cereal-producing land showed that 69% of fields contained CCN cysts and of these 54% contained eggs. CCN infestations were more frequent in SE and NE areas. Populations were small despite intensive cereal cropping, 71% having less than 1 egg/g soil and only 3% having more than 6 eggs/g soil. Soil type and cropping frequency were important in influencing the infestation of fields with CCN. Infested fields occurred most frequently in freely draining loamy-drift soils and populations were larger when these infested soils were cropped more frequently with cereals. In the soils that were less well draining, fewer infestations occurred and cropping frequency was less important, although cropping with oats in these soils was associated with larger CCN populations. A survey of seed-potato-producing land showed that 55% of fields known to contain CCN had viable populations but that population densities were smaller than in the more intensively cereal-cropped fields.     

The effect of metribuzin interaction with potato viruses X and Y on potato foliage,yield and grade

Foliar treatment of potato (Solanum tuberosum L.) with metribuzin at 0.57–1.0 lb/A caused a necrotic reaction in leaflets of plants infected with potato virus Y (PVY), but not in plants infected with potato virus X (PVX) or potato leafroll virus. Necrosis symptoms resulting from metribuzin-PVY interaction were distinct from symptoms of either PVY infection or of metribuzin injury. This reaction was similar in the Russet Burbank, Lemhi Russet, and Pioneer cultivars. Russet Burbank infected with PVY and PVX, alone or in combination, was treated with metribuzin to study herbicidevirus interaction effects on yield. Secondary PVY infection alone caused a 57% yield reduction, and when combined with PVX caused a 71% yield reduction. Although leaflet necrosis was induced by the metribuzin-PVY combination, there was no significant yield interaction. Results suggest that post-emergence application of metribuzin can be used as an aid for detecting and removing potato virus Y infected plants from potato seed fields     

The effect of soil pH on yield losses caused by the potato cyst nematodeGlobodera pallida

Summary The effect of soil pH on yield losses due to potato cyst nematodes (Globodera pallida) was investigated in experiments in the field and in a semi-controlled environment. Through annually liming a reclaimed peat soil with about 22% organic matter, plots with pH levels of 4.5, 5.0, 5.5, 6.0 and 6.5 were obtained. In 1990 potato yields in these plots decreased from 45 t/ha at pH 4.5 to 33 t/ha at pH 6.5, whereas the nematode densitites decreased from about 18 to 9 juveniles per g soil. In a container experiment a strong interaction was recorded between soil pH and the presence of nematodes. Tuber yields were about 11% lower at pH 6.5 than at pH 4.5 in the absence of nematodes, but about 44% lower when an initial population of 27 juveniles per g soil was present.     

The effect of wilting and silage additives on the fermentation of autumn made grass silage ensiled in bunkers on commercial farms in South Wales 1983-85

Silage making practices in respect of 130 samples of autumn made grass silages ensiled in bunkers on commercial farms in South Wales during 1983-1985 were analysed to discern the effect of wilting and/or silage additives on fermentation. Silages were primarily made during late September and early October in fine weather from perennial ryegrass pasture which had not been grazed for 6 weeks. On average 13.9 ha of pasture was cut for silage. Analysis of 120 samples of grass showed it contained 176 g kg^?1 dry matter (DM) with (g kg^?1 DM) 215 protein, 240 modified acid detergent fibre (MADF), 78 water-soluble carbohydrate (WSC) and 95 ash. Most farmers attempted to pre-wilt grass for 1 day prior to ensilage and one quarter of them made unwilted silage. Silage making was usually completed within 6 days of starting to cut and was generally made with a precision-chop machine. Silage additives applied were (kg t^?1) formic acid (4·7), formic acid 4-formalin (5·5), sulphuric acid-+ formalin (5·0) sugars (14) and inoculants (0·65). Formic acid significantly reduced pH, and formic acid with or without formalin significantly reduced ammonia nitrogen (N) content of silages compared with other treatments. Protein contents of acid/formalin treated silages were significantly higher and MADF of acid with or without formalin treated silages were significantly lower than other treatments. Pre-wilting grass prior to ensilage did not significantly increase subsequent silage DM content and significantly increased the pH of non-additive treated silages. Unwilted silages treated with formic acid with or without formalin had a significantly lower ammonia-N content and higher residual WSC than other treatments. It is suggested that only formic acid application either alone or in conjunction with formalin to unwilted silage was successful in producing well preserved silages and that a grass WSC content of 17 g kg^?1 would be necessary to achieve this.