Micropropagation of Pinus densiflora and the evaluation of nematode resistance of regenerated microshoots in vitro

To accelerate the breeding and selection of Pinus densiflora Siebold and Zucc. resistance to pine wilt disease, a micropropagation system was established and nematode resistance evaluated in vitro. Cotyledon-hypocotyl explants from 28-day-old seedlings were first cultured on Gresshoff and Doy medium supplemented with 4.0 mg L^-1 6-benzyladenine and 0.2 mg L^-1 a-naphthaleneacetic acid(NAA) to stimulate the formation of buds. Induced buds were subsequently subcultured on Gupta and Durzan medium supplemented with 0.1%(w/v)activated charcoal for elongation. Stem sections derived from shoots were used as explants for the further multiplication. Roots were formed from shoots transferred to woody plant medium containing 0.2 mg L^-1 NAA for4 weeks. The nematode resistance test showed that symptoms in micropropagated shoots after infection with pine wood nematode(PWN) were similar to those in plants infected in the field. The wilting rate varied from 20 to100% among different clones 18 days after inoculation.The most susceptible clone was Clone 6-4 with a 100%wilting rate, while Clone 8-4 showed a relatively high resistance with a 20% wilting rate. The number of nematodes recovered from Clone 8-4 shoots was significantly lower(P = 0.05) than from Clones 5-10 and 16-4. This work contributes to the breeding of PWN resistance in P.densiflora.     

Effects of 1,3-dichloropropene on nematode,weed seed viability and soil-borne pathogen

1,3-dichloropropene (1,3-D, C₃H₄Cl₂) is one of the potential candidates as soil disinfectant since the restriction of methyl bromide (MeBr) in soil fumigation due to its ecological risk. Its nematode, soil-borne pathogen and weed control efficacies were evaluated in a laboratory dose-response study and in two commercial tomato fields. Laboratory studies found that the seeds of Digitaria chinensis Hornem. were the most sensitive to soil fumigation with 1,3-D, followed by Eleusina indica (Linn.) Gaertn., Echinochloa crusgalli (L.) Beauv. and Amaranthus retroflexus L. with the LC₉₀ values between 14.23 and 73.59 mg kg⁻¹ soil. Among the pathogens, Phytophthora capsici Leonian was the most sensitive and Fusarium oxysporum f. sp. fragariae was the least sensitive to 1,3-D fumigation with the LC₅₀ values were 0.24 and 1.55 g m⁻². Rhizoctonia solani Kühn., Phytophthora nicotianae var. nicotianae and Botrytis cinerea Persoon exhibited intermediate susceptibility. Field trials revealed that 1,3-D applied to the field at 180, 120 and 80 L ha⁻¹ could suppress Meloidogyne incognita root galling while maintaining high tomato marketable yields, better than Dazomet at the concentration of 400 kg ha⁻¹. Our results indicated that 1,3-D was an excellent nematicide and could provide good to moderate weed and pathogen control. Based on our results, 1,3-D, in combination with other alternatives to MeBr is recommended to reach an integrated pest management.     

三种无公害药剂对新疆杨线虫防治效果试验

线虫病是危害新疆杨的一种重要害虫,采用10%除虫脲、25%阿维菌素、1.2%苦烟乳油三种杀虫剂进行灌根和土壤处理,防治后调查新疆杨线虫病的减退率,其中以除虫脲500倍液的处理减退率最大,根灌效果好于土壤处理。     

两种生物制剂对植物寄生线虫防效的室内测定

[目的]筛选具有较好杀线虫效果的生物杀线虫剂。[方法]使用0．3％印楝素乳油和2．0％的阿维菌素乳油对供试线虫进行了生物测定。[结果]0．3％印楝素乳油的LC50为1．05g/L,而2．0％的阿维菌素乳油的LC50为1．09g／L。[结论]0．3％印楝素乳油和2．0％的阿维菌素乳油对植物寄生线虫的致死活性相当。     

烟草根结线虫病防治药剂的田间筛选研究

 通过田间试验,分析比较不同药剂（措施）处理对烤烟生长特性、产值、产量以及对根结线虫病发病情况的影响。结果表明,施用5%神农丹颗粒剂3g/株+0.5%肯邦线尊颗粒剂3g/株,防效最好,相比于对照,平均防效为（74.52±6.57）%,烟叶产值和均价也最高,分别达到（3.2495±177.03）元/hm2（12.89± 0.11）元/kg。施用05%肯邦线尊颗粒剂防效次之,其平均防效在（66.87±7.84）%。施用腐熟农家肥烟叶产量最高,达到（2.979±210.72）kg/hm2。因此,增施有机肥,施用5%神农丹颗粒剂+05%肯邦线尊颗粒剂,是防治烟草根结线虫病,增加效益,促进烟草产业可持续发展的有效措施。     

长白山林区中国林蛙体内肺线虫调查

通过解剖镜检测分析了长白山林区不同地点、年龄组、性别及生活期中国林蛙肺线虫的感染情况.结果表明：中国林蛙肺线虫为双角棒线虫（Rhabdia bufonis）,感染率为81.5%.不同地点肺线虫感染率差异不显著（P﹥0.05）,不同地点肺线虫平均感染强度差异显著（P〈0.05）;不同年龄林蛙的肺线虫感染率差异较大,成体感染率及感染强度均大于幼体;不同性别的肺线虫感染差异不显著.长白山林区中国林蛙肺线虫感染率及感染强度较高,虫源分布广,认为是林蛙自然死亡的原因之一.     

食线虫担子菌对线虫的作用效果

为筛选新的食线虫担子菌,了解食线虫担子菌对线虫的作用方式,以提高食线虫真菌生防能力,收集贵阳地区担子菌,在平板上获得纯培养54株担子菌,以Panagrellus redivivus为靶标进行了初步杀线虫效果的测定和作用线虫方式的观察。结果表明,处理线虫48h,线虫死亡率在80%以上的菌株19株,其中,有4株(毛头鬼伞、大球盖菇、粗皮侧耳野生株和齐整小核菌)的死亡率达100%;担子菌菌丝作用线虫的方式有毒素球毒杀兼寄生、星状体降解虫体、毒杀兼寄生、菌丝束缚和代谢物降解虫体。     

Spatio-temporal consideration of soil conditions and site-specific management of nematodes

Site-specific (precision) management (SSM) has potential for application in managing nematodes and soil conditions in environmentally meaningful ways. Successful application of SSM, however, may be dependent on how agronomically, biologically, and ecologically integrated the plan in question is. Otherwise, SSM risks falling into the “Tried but did not last” category. With this background and in addition to describing the concepts and principles of SSM, this presentation discusses the following interrelated points: (1) Case studies of spatio-temporal analysis of soybean cyst nematode (Heterodera glycines) infestations, soil conditions and crop yield in managed ecosystems. Among the critical factors to an accurate and sustained application of SSM are understanding (i) the temporal structure and (ii) the spatial structure of the attribute in question, and (iii) establishing cause-and-effect relationships in the prevailing conditions. New approaches to temporal structure analysis when balancing the purpose of SSM application and nematode biology (as it relates to life stages), population density in soil and root tissue (to determine threshold), and damage functions (physiological stress of the plant during the growing season) are outlined. (2) Application of the concept of fertiliser use efficiency (FUE) to identify soil conditions when managing soil fertility. Defined as increase in host productivity and/or decrease in plant-parasitic nematode population density in response to a given fertiliser treatment, the FUE model recognizes variable responses and identifies four categories of interactions necessary for integrated management decision-making options that account for agronomic, economic, ecological and environmental and pest management issues. (3) Approaches to changing soil conditions in agro-biologically integrated ways. By incorporating nematode community structure (an excellent indicator of soil bio-ecological changes), soil nutrient amendments and crop yield, we have described a modification of the FUE model to identify and monitor changes in soil conditions, thereby creating the necessary bridges to disciplinary and cross-disciplinary gaps and interactions.     

富锦市大豆孢囊线虫危害现状及其防治措施

富锦是黑龙江东部重要的大豆生产基地,播种面积16万hm^2以上,占全市耕地面积的50%。连年的重迎茬种植,加快了大豆孢囊线虫的繁殖和孢囊在土壤中的积累。大豆孢囊线虫病是富锦市大豆重迎茬显著减产、持续减产的主要原因。应用抗病品种是防治大豆孢囊线虫最经济有效的措施。抗线虫大豆品种的应用取得了极显著地抗病增产效果,累计推广面积达15万hm^2以上。     

水稻-番茄轮作植物寄生线虫及微生物群落结构差异

土壤线虫和微生物群落结构与作物健康密切相关。采用田间试验，利用传统分类和高通量测序技术，研究了水稻–番茄轮作(FS)、番茄连作(FF)和休耕(CK)3种种植制度土壤线虫及微生物群落结构差异。结果表明，水旱轮作土壤中线虫种类少，自由生活线虫占比高。土壤中植物寄生线虫属的检出率，轮作最少，仅有5个，连作最多，共13个，且大部分为常见属；水旱轮作同时能降低土壤中植物寄生线虫的种类，包括主要危害番茄的根结线虫属，占比仅2.1%，而连作为29.7%。不同种植制度下真菌和细菌类群OUTs和群落结构差异明显；与连作相比，轮作和休耕真菌、细菌种群丰富度更高，共享占比更多，群落构成更相近；水旱轮作Alpha多样性指数显著高于连作；轮作土壤中植物寄生线虫拮抗微生物类群Chaetomium,Talaromyces,Anaerolineaceae和Acidobacteria相对丰度高于连作。水稻–番茄轮作能大幅减少植物寄生线虫种类，增加微生物群落多样性，改善土壤质量，是番茄生产中防控线虫病害的理想措施。