PANS Plant Growth Regulator Index: A List of Chemical,Coded, Common and Trade Names

Abstract

Laboratory experiments were carried out on populations of the leucaena psyllid (Heteropsylla cubana Psyllidae) and two parasitoids, Psyllaephagus yaseeni (Encyrtidae) and Tamarixia leucaenae (Eulophidae) to determine to what extent the parasitoids compete. When both parasitoids were introduced to caged populations of the psyllid, fewer mummies were produced than when equivalent numbers of P. yaseeni alone were introduced. Multiparasitism was confirmed by dissection. The extent of multiparasitism was found to be dependent on the number of unparasitized psyllid nymphs available to T. leucaenae. Behavioural observations indicated that T. leucaenae tends to avoid searching and ovipositing on plants previously exposed to P. yaseeni. Superparasitism occurs in P. yaseeni but the distribution of attacks suggests that females discriminate between parasitized and unparasitized hosts and avoid ovipositing in the former. Superparasitism by T. leucaenae is very rare and was not recorded In this study.     

亮腹釉小蜂成虫触角感受器的超微结构

为进一步了解柑橘木虱Diaphorina citri若虫的优势寄生蜂亮腹釉小蜂Tamarixia radiata的寄生行为,利用扫描电镜对亮腹釉小蜂雌雄成虫触角感受器的种类、分布和形态进行观察。结果表明,亮腹釉小蜂雌成虫触角上存在5种感受器,分别是刺形感受器、毛形感受器、乳头状感受器、板形感受器和末端指形感受器;亮腹釉小蜂雄成虫触角上存在4种感受器,分别为刺形感受器、毛形感受器、乳头状感受器和板形感受器;其中毛形感受器又可以根据外部形态的差异划分为4个亚型,即毛形感受器类型1、2、3、4。此外,板形感受器、毛形感受器类型2和毛形感受器类型3在亮腹釉小蜂雌成虫触角上的分布数量显著多于雄成虫触角上的分布数量。这些形态学差异有助于深入理解不同性别亮腹釉小蜂的触角感知行为。     

Potential of <Emphasis Type="Italic">Trichoderma</Emphasis> spp. and <Emphasis Type="Italic">Talaromyces flavus</Emphasis> for biological control of potato stem rot caused by <Emphasis Type="Italic">Sclerotinia sclerotiorum</Emphasis>

Sixteen isolates belonging to 11 species of Trichoderma (T. asperellum, T. ceramicum, T. andinensis, T. orientalis, T. atroviride, T. viridescens, T. brevicompactum, T. harzianum, T. virens, T. koningii and T. koningiopsis) were evaluated for biological control of potato (Solanum tuberosum) stem rot caused by Sclerotinia sclerotiorum. In dual culture tests, all antagonists significantly reduced sclerotia formation, and were able to inhibit radial growth of the pathogen. Growth inhibition by production of volatile and non-volatile inhibitors was also measured in in vitro tests. In screening the most efficient species of Trichoderma, establishment of mycelium on sclerotia and sclerotia lysis were also considered as important biocontrol qualities. Excluding T. asperellum, T. brevicompactum, T. andinensis and T. harzianum, all tested Trichoderma species were able to lyse sclerotia. The sclerotia-destroying species of Trichoderma and one isolate of Talaromyces flavus were tested in greenhouse tests and during 2 years of field experimentation during the 2007 and 2008 cropping seasons. After one aerial application of spore suspension in greenhouse trials, T. koningii, T. virens, T. ceramicum and T. viridescens were the most effective bio-agents and reduced significantly disease severity, and the least biocontrol efficacy was observed in T. flavus. Under field conditions and after five soil and foliar applications of spore suspension, all tested antagonists reduced significantly disease incidence. T. viridescens followed by T. ceramicum showed the best results. T. flavus and T. orientalis were less effective than other tested antagonists in both field trials.     

Bioefficacy of Trichoderma Species Against Javanese Root-Knot Nematode,Meloidogyne javanica,in Green Gram

Root-knot nematodes are mainly controlled by using synthetic nematicides, but their excessive use is prohibited due to associated health hazards which demand for suitable alternatives. The overreliance on nematicides can be curtailed by using biological control agents possessing nematicidal or nematostatic properties. Therefore, in the present study, effectiveness of seven indigenous species of Trichoderma were tested for their ability to suppress the population of Javanese root-knot nematode, Meloidogyne javanica, and improve growth variables of green gram. All the Trichoderma species resulted in an increase in shoot and root lengths and shoot weight while a decrease was observed in root weight. Maximum increase in shoot length (45.5%) was found in case of T. harzianum followed by T. hamatum and T. viride whereas the increase was the minimum where T. pseudokoningii and T. koningii were applied. Similarly, maximum increase in shoot weight was recorded with T. viride (56.1%) followed by T. harzianum (55%) and the minimum with T. pseudokoningii. As regards root length, it was the maximum in treatments with T. hamatum (46.2%) and T. harzianum (45.1%) and minimum with those where T. koningii and T. pseudokoningii were applied. Contrarily, maximum reduction in root weight was observed in treatments where T. harzianum (37.8%) and T. viride (35.8%) were applied while T. koningii and T. pseudokoningii resulted in minimum decrease. All the Trichoderma species significantly caused reductions in the number of galls and eggs and reproductive factor of the nematode over control. Maximum reduction in numbers of galls and eggs were observed with T. viride (49 and 53%) followed by T. harzianum (46 and 53%) while the minimum reduction was recorded with T. pseudokoningii followed by T. atroviride. Likewise, T. viride caused the maximum reduction in reproductive factor of M. javanica (81%) followed by T. harzianum (78%) and T. asperellum (75%). On the other hand, the minimum reductions in reproductive factor were observed with T. pseudokoningii and T. koningii.

     

Development of a PCR-based diagnostic tool specific to wheat dwarf bunt,caused by <Emphasis Type="Italic">Tilletia controversa</Emphasis>

Wheat dwarf bunt, one of the important international quarantine diseases, is caused by Tilletia controversa. Tilletia caries is a close relative species of T. controversa and the teliospore morphology and genomic structure of T. caries are very similar to those of T. controversa. In order to distinguish between them, a random amplified polymorphic DNA (RAPD) primer-mediated asymmetric-PCR (RM-PCR) was developed to screen differential sequences between the two pathogens. By RM-PCR, a 1,322 bp DNA fragment (PR32) was selected from 18 T. controversa and 29 T. caries strains. The PR32 genes were specific for T. controversa and almost had no homology to T. caries or other fungi in the present database. With primers designed from PR32, all 18 T. controversa strains were amplified, but no bands appeared in 29 T. caries strains by classical PCR. To identify T. controversa rapidly and accurately, SYBR Green I and TaqMan probe real-time PCR were established based on PR32. With TaqMan Real-Time PCR, different T. controversa strains and T. caries strains were detected. The results showed that all T. controversa strains were amplified with Ct from 19–29 and amplified curves were obtained. In contrast, the amplification of all T. caries strains did not show any signals, without Ct and amplified curves. Moreover, the developed TaqMan real-time PCR was used to detect T. controversa from asymptomatic wheat tissues successfully.     

Composition and toxic, repellent and feeding deterrent activity of essential oils against the stored-grain pests Tribolium castaneum (Coleoptera: Tenebrionidae) and Sitophilus oryzae (Coleoptera: Curculionidae)

BACKGROUND: The composition and bioactivity of essential oils from Tagetes terniflora Kunth, Cymbopogon citratus Stapf. and Elyonurus muticus (Spreng) Kuntz were evaluated against stored‐grain pests. RESULTS: Fumigant and contact toxicities were observed with T. terniflora on adults of both pests. In contact toxicity, this oil was less toxic to Tribolium castaneum (Herbst). Essential oils from C. citratus and E. muticus showed contact toxicity on S. oryzae. All essential oils produced: (a) repellency on larvae and adults of T. castaneum and adults of Sitophilus oryzae (L.); (b) post‐ingestive toxicity on T. castaneum larvae and S. oryzae adults and alteration of nutritional index on T. castaneum and S. oryzae adults. Cymbopogon citratus reduced the relative growth rate and the efficiency of conversion of ingested food in T. castaneum larvae. Tagetes terniflora produced a feeding stimulant effect in T. castaneum adults. In addition, they had a feeding deterrent action against S. oryzae adults. The composition of essential oils from C. citratus and E. muticus varied only in one component. CONCLUSION: These results showed that the essential oils from T. terniflora, C. citratus and E. muticus should be studied further for their use in integrated pest management programmes for T. castaneum and S. oryzae control. Copyright © 2011 Society of Chemical Industry     

Parasitism of <Emphasis Type="Italic">Trichoderma</Emphasis> on <Emphasis Type="Italic">Meloidogyne javanica</Emphasis> and role of the gelatinous matrix

Trichoderma (T. asperellum-203, 44 and GH11; T. atroviride-IMI 206040 and T. harzianum-248) parasitism on Meloidogyne javanica life stages was examined in vitro. Conidium attachment and parasitism differed beween the fungi. Egg masses, their derived eggs and second-stage juveniles (J2) were parasitized by Trichoderma asperellum-203, 44, and T. atroviride following conidium attachment. Trichoderma asperellum-GH11 attached to the nematodes but exhibited reduced penetration, whereas growth of T. harzianum-248 attached to egg masses was inhibited. Only a few conidia of the different fungi were attached to eggs and J2s without gelatinous matrix; the eggs were penetrated and parasitized by few hyphae, while J2s were rarely parasitized by the fungi. The gelatinous matrix specifically induced J2 immobilization by T. asperellum-203, 44 and T. atroviride metabolites that immobilized the J2s. A constitutive-GFP-expressing T. asperellum-203 construct was used to visualize fungal penetration of the nematodes. Scanning electron microscopy revealed the formation of coiling and appressorium-like structures upon attachment and parasitism by T. asperellum-203 and T. atroviride. Gelatinous matrix agglutinated T. asperellum-203 and T. atroviride conidia, a process that was Ca²⁺-dependent. Conidium agglutination was inhibited by carbohydrates, including fucose, as was conidium attachment to the nematodes. All but T. harzianum could grow on the gelatinous matrix, which enhanced conidium germination. A biomimetic system based on gelatinous-matrix-coated nylon fibers demonstrated the role of the matrix in parasitism: T. asperellum-203 and T. atroviride conidia attached specifically to the gelatinous-matrix-coated fibers and parasitic growth patterns, such as coiling, branching and appressoria-like structures, were induced in both fungi, similarly to those observed during nematode parasitism. All Trichoderma isolates exhibited nematode biocontrol activity in pot experiments with tomato plants. Parasitic interactions were demonstrated in planta: females and egg masses dissected from tomato roots grown in T. asperellum-203-treated soil were examined and found to be parasitized by the fungus. This study demonstrates biocontrol activities of Trichoderma isolates and their parasitic capabilities on M. javanica, elucidating the importance of the gelatinous matrix in the fungal parasitism.     

不同秸秆覆盖耕种模式对半干旱区玉米生长发育及水分利用的影响

研究合理的秸秆覆盖耕种模式是实现半干旱区秸秆覆盖条件下玉米绿色高效生产的重要途径。开展2 a大田试验,设置传统耕作模式(CK)、秸秆覆盖模式(T1)、秸秆覆盖+深松模式(T2)、秸秆覆盖+碎混模式(T3)4个处理,研究不同秸秆覆盖耕种模式对玉米根系伤流特性、光合特性、碳氮代谢相关酶活性、生长发育、产量及其构成因素和水分利用特性的影响。结果表明：不同处理玉米根系伤流强度、伤流液中细胞分裂素(CTK)和生长素(IAA)含量均表现为T3>T2>CK>T1,脱落酸(ABA)含量表现为T1>CK>T2>T3;与CK和T1处理相比,T2与T3处理的CTK和IAA含量显著增加、ABA含量显著下降。玉米叶片净光合速率(P_n)、气孔导度(G_s)、胞间二氧化碳浓度(C_i)、蒸腾速率(T_r)、表观叶肉导度(AMC)和叶片水分利用效率(WUEL)均表现为T3>T2>CK>T1,气孔限制百分率(L_s)表现为T3相似文献   

Trichoderma species associated with green mould disease of Pleurotus ostreatus and their sensitivity to prochloraz

Green mould disease causes serious economic losses in Pleurotus ostreatus crops worldwide, including in Italy, where prochloraz is the only chemical fungicide allowed to control the disease. The effectiveness of the doses 0.01, 0.05, 0.25 and 1.25 μL L⁻¹ (field dose) of prochloraz (Sponix Flow, 450 g L⁻¹), against colony growth rate and spore germination of Trichoderma pleuroti, T. pleuroticola and T. guizhouense strains on wheat straw extract agar plates were evaluated. Complete inhibition of Trichoderma pleuroti and T. pleuroticola growth was shown by the field dose of prochloraz, and also by the 0.25 μL L⁻¹ dose for T. pleuroti. Complete inhibition of spore germination occurred for all Trichoderma strains at field dose, and at 0.25 μL L⁻¹ for T. pleuroti strains. In in vivo assays, the effect of prochloraz doses 0.05, 0.25 and 1.25 μL L⁻¹ on colonization of straw substrate by T. pleuroti, T. pleuroticola and T. guizhouense inoculated at two spore densities (10² and 10⁵ spores mL⁻¹) immediately after P. ostreatus spawn was studied. Trichoderma pleuroti and T. pleuroticola were both responsible for green mould disease, whereas T. guizhouense was not pathogenic. Trichoderma pleuroti was more aggressive than T. pleuroticola. Prochloraz was effective against T. pleuroti at the field dose, and against T. pleuroticola at 0.25 and 1.25 μL L⁻¹. The study on Trichoderma × Pleurotus interaction type showed that Trichoderma species were active against the mycelial growth of P. ostreatus by competition for space and nutrients, and neither hyphal interaction nor effect by volatile or nonvolatile metabolites occurred.     

稻螟赤眼蜂蛹期接触农药对其成蜂搜寻和寄生能力的影响

稻螟赤眼蜂Trichogramma japonicum是稻田中鳞翅目害虫重要的卵期寄生型天敌,为了规范稻螟赤眼蜂放蜂期农药的安全使用,利用卵卡浸渍法处理蛹期稻螟赤眼蜂,通过稻螟赤眼蜂室内飞行装置和单雌寄生法评估了蛹期5种非鳞翅目害虫靶标农药井冈霉素、三唑酮、吡蚜酮、印楝素、毒死蜱对稻螟赤眼蜂成蜂搜寻和寄生能力的影响。搜寻能力结果显示,在毒死蜱处理后稻螟赤眼蜂失去搜寻能力,三唑酮、吡蚜酮和印楝素处理对稻螟赤眼蜂的搜索行为无影响,但井冈霉素处理下稻螟赤眼蜂的飞行蜂比例为48.1%,显著低于对照处理的74.7%。寄生能力结果显示,毒死蜱处理对稻螟赤眼蜂高毒,能使稻螟赤眼蜂失去寄生能力;印楝素处理对稻螟赤眼蜂的寄生力和子代羽化率无显著影响;井冈霉素、三唑酮和吡蚜酮处理下稻螟赤眼蜂的寄生力分别为22.2、25.3和24.7,显著低于对照的27.4、31.1和29.6,但对子代羽化率无显著作用。表明印楝素对稻螟赤眼蜂安全,可以推广使用;井冈霉素、三唑酮和吡蚜酮对稻螟赤眼蜂的搜索能力(仅井冈霉素)和寄生能力有显著的削弱作用,应谨慎使用;毒死蜱对稻螟赤眼蜂高毒,在稻螟赤眼蜂放蜂期应该禁用。     

2,4-表油菜素内酯对干旱胁迫下垂丝海棠生理特性的影响

以7～8叶龄的垂丝海棠实生苗为试验材料,研究外源喷施2,4-表油菜素内酯（EBR）对干旱胁迫下垂丝海棠幼苗光合及生理特性的影响。采用盆栽控水法,设置CK（正常水分）与干旱胁迫加6种浓度油菜素内酯处理,即T1(0 mg·L^-1)、T2(0.20 mg·L^-1)、T3(0.40 mg·L^-1)、T4(0.60 mg·L^-1)、T5(0.80 mg·L^-1)和T6(1.00 mg·L^-1),分别测定各处理下叶绿素含量、光合特性、抗氧化酶活性及渗透调节物质含量,并进行相关性与主成分分析。随干旱胁迫时间的延长,垂丝海棠叶片的Chl a、Chl b、Chl a+b、Chl a/b、净光合速率（P_n）、气孔导度（G_s）和蒸腾速率（T_r）均呈下降趋势;胞间CO₂浓度（C_i）、丙二醛（MDA）含量和相对电导率（REC）呈上升趋势;脯氨酸（Pro）含量、超氧化物歧化酶...     

雪松疫霉(Phytophthora lateralis)的快速分子检测

由雪松疫霉(Phytophthora lateralis)引起的疫病是一类植物检疫性病害。为建立该病原菌的快速检测技术,本文比较分析了雪松疫霉和其他疫霉的tRNA序列,在此基础上设计了一对检测雪松疫霉的特异性引物T1/T2,该对引物从雪松疫霉中扩增得到1条192 bp的条带,而其他15种疫霉和其他真菌菌株均无扩增条带,表明该对引物对雪松疫霉具有特异性。在25μL PCR反应体系中,引物T1/T2检测灵敏度为10 pg基因组DNA;而以引物T3/T4和T1/T2进行巢式PCR扩增,能够检测到1 fg基因组DNA,使检测灵敏度提高了10 000倍。该检测体系对灭菌水中游动孢子的检测灵敏度可达0.5个游动孢子,对人工接种发病的植物组织能够特异性地检测到该病原菌。此外,进一步建立了该病原菌的实时荧光定量PCR检测体系。     

生物菌肥和钾肥配施对苹果钾素吸收及果实品质的影响

为了研究生物菌肥和钾肥对苹果果实品质及生长发育的协同作用,以7 a生'瓦里短枝'(Vallee spur Del)为研究对象,设置T1(K2O 420 kg·hm-2)、T2(生物菌肥2520 kg·hm-2)、T3(生物菌肥2520 kg·hm-2+K2O 294 kg·hm-2)、T4(生物菌肥2520 kg·hm...     

Trichoderma harzianum T39 and T. virens DAR 74290 as Potential Biological Control Agents for Phytophthora erythroseptica

Trichoderma harzianum isolate T39 and T. virens isolate DAR 74290 were evaluated as potential biological agents for control of pink rot of potato and root and stem rot of tomato caused by Phytophthora erythroseptica. Cell-free metabolites of T. virens DAR 74290 completely inhibited growth of P. erythroseptica in vitro and appeared to be fungicidal. T. virens DAR 74290 and Trichodex, a commercial formulation of T. harzianum T39, were tested for their ability to protect potato and tomato plants from disease caused by P. erythroseptica in glasshouse experiments. Trichodex and T. virens DAR 74290, alone and combined, reduced disease severity in shoots and roots of potatoes 10 weeks after inoculation with the pathogen. The yield of potatoes from plants treated with P. erythroseptica and T. virens DAR 74290 (mean of 12.9g fresh weight/pot) was significantly greater than in controls inoculated with the pathogen alone (mean of 2.1g/pot). Treatment with Trichodex alone increased the yield of tubers compared to the uninoculated controls. T. virens DAR 74290 increased the survival of tomato seedlings inoculated with the pathogen, and both this isolate and Trichodex decreased the severity of disease on tomato.     

食物对兹沃尔新小绥螨生长发育和繁殖的影响

为探究不同食物对兹沃尔新小绥螨Neoseiulus zwoelferi种群生长、发育和繁殖的影响,采用年龄-龄期两性生命表分析测定兹沃尔新小绥螨取食卢氏叶螨Tetranychus ludeni、甜果螨Carpoglyphus lactis和香蒲Typha orientalis花粉后的存活率、发育历期、寿命及繁殖情况。结果显示,3种食物均能满足兹沃尔新小绥螨生长发育和繁殖的需求。卢氏叶螨处理组的净增殖率和总繁殖率分别是28.99和36.99,均显著高于其他2个处理组;以甜果螨、卢氏叶螨和香蒲花粉为食的兹沃尔新小绥螨从卵发育至成螨所需时间分别为5.28、7.34和6.87 d,种群倍增时间分别3.35、4.22和11.77 d,前者显著短于其他2个处理;甜果螨处理组和卢氏叶螨处理组的雌成螨平均寿命分别比香蒲花粉处理组长2.75 d和4.92 d,但两者之间无显著差异;卢氏叶螨处理组雌成螨产卵天数最长,为17.84 d,产卵前期时间最短,为2.75 d,产卵量最大,为38.15粒/雌;香蒲花粉处理组雌成螨产卵天数最短,仅1.82 d,产卵前期时间最长,为5.89 d,产卵量最少,为3.36粒/雌。甜果螨处理组的内禀增长率、周限增长率分别为0.21 d-1和1.23 d-1,均显著高于其他处理组,但平均世代周期为14.65 d,显著低于其他处理组。表明3种食物均可使兹沃尔新小绥螨完成整个世代,其中甜果螨是室内饲养兹沃尔新小绥螨的最佳食物,香蒲花粉可以作为短期饲养的食物。     

Selective accumulation of Trichoderma species in soils suppressive to radish damping-off disease after repeated inoculations with Rhizoctonia solani, binucleate Rhizoctonia and Sclerotium rolfsii

Artificial suppression of radish damping-off disease was induced by repeated soil inoculations with Rhizoctonia solani, binucleate Rhizoctonia (BNR) and Sclerotium rolfsii in pot systems. Soils repeatedly inoculated with R. solani and BNR showed suppressive to disease caused by R. solani and S. rolfsii, while soils repeatedly inoculated with S. rolfsii were suppressive to disease caused by S. rolfsii but not by R. solani. Species of Trichoderma were consistently isolated from soils repeatedly inoculated with R. solani, BNR and S. rolfsii. These Trichoderma spp. accumulated selectively in relation to the fungal species that was repeatedly added to the soils. The ratios of the frequencies of T. viride, T. harzianum and T. hamatum were 5:2:2 and 8:5:2 in soils repeatedly inoculated with R. solani and BNR, respectively. In S. rolfsii- inoculated soils, T. koningii was predominantly isolated. T. viride, T. harzianum and T. hamatum isolates obtained from either R. solani or BNR after repeated additions to the soils suppressed radish damping-off disease caused after challenge inoculations with R. solani or S. rolfsii. Among the Trichoderma species, T. viride consistently yielded high levels of suppression. However, isolates of T. koningii obtained from S. rolfsii-infested soils suppressed disease caused by S. rolfsii but failed to suppress disease caused by R. solani. Generally, the species of Trichoderma accumulated in a selective pattern that was closely related to the species of fungal pathogen used to induce the suppressive soil.     

Detection of viridiofungin A and other antifungal metabolites excreted by <Emphasis Type="Italic">Trichoderma harzianum</Emphasis> active against different plant pathogens

Antibiosis is assumed to be an essential mechanism exerted by potential biocontrol agents (BCAs) of Trichoderma spp. Therefore, in the present study, we report for the first time on the elucidation and production of viridiofungin A (VFA) from T. harzianum isolate T23 cultures and investigate the antifungal potential of VFA and some other secondary metabolites purified from T. harzianum cultures against Fusarium moniliforme. The bioautography assay revealed that T. harzianum isolates T16 and T23 excreted several secondary metabolites with antifungal activity. Following isolation and purification of the antifungal zones, three fractions (F223, F323 and F423) from extracts of isolate T23 and two fractions (F416 and F516) from extracts of isolate T16 exhibited pronounced fungitoxic activity in the bioautography and antibiotic disk assays against Cladosporium spp. and F. moniliforme, respectively. The structure of the antifungal metabolite in fraction F323 was identified as viridiofungin A (VFA), the first report of production of VFA by isolate T23 of T. harzianum. Following cultivation of isolate T23 in PDB medium for 9 days, 94.6 mg l⁻¹ of VFA were determined. VFA and fraction F516 retarded the mycelial growth of F. moniliforme in the non-volatile phase assay by >90% for each 250 μg ml⁻¹ 7 days post-inoculation (dpi). While VFA and fraction F416 showed both volatile and non-volatile effects, fraction F516 seemed to exhibit mainly non-volatile activity. Microscopic examination revealed that hyphae of F. moniliforme grown on VFA-amended medium were less branched and appeared thicker than untreated hyphae. Furthermore, in the presence of VFA, formation of chlamydospores by F. moniliforme was increased. Finally, the antifungal spectrum of VFA towards various important plant pathogens was evaluated. Germination of propagules of a variety of fungal pathogens in vitro was differentially inhibited by VFA. While in the presence of 100 μg ml⁻¹ VFA conidial germination of V. dahliae was completely inhibited, a slightly higher concentration (150 μg ml⁻¹) of the inhibitor was required to suppress germination of Phytophthora infestans sporangia or sclerotia of Sclerotinia sclerotiorum. Contrary to several reports in the literature, VFA proved to be fungistatic rather than fungicidal. However, neither VFA nor the other Trichoderma metabolites, such as 6PAP, F416 and F516, exhibited any antibacterial activity against Gram-positive and Gram-negative bacteria.     

The Use of a GUS Transformant of Trichoderma Harzianum, Strain T3a, to Study Metabolic Activity in the Spermosphere and Rhizosphere Related to Biocontrol of Pythium Damping-off And Root Rot

The activity of Trichoderma harzianum in the spermosphere and rhizosphere of different plant species was studied by use of a beta-glucuronidase (GUS) transformant (strain T3a). Hereby, direct observation of micro-habitats supporting metabolic activity of T. harzianum is reported. Germination of conidia and mycelial growth were not supported by exudates from healthy roots of various ages. Instead, growth and activity of T. harzianum depended on access to dead organic substrates such as seed coats, decaying roots, and wounds, including those caused by infecting pathogens. A correlation between the GUS activity of T. harzianum and the biomass of Pythium ultimum in infected roots was established. On the basis of our observations, we suggest that the biocontrol ability of T. harzianum involves competition with the pathogen for substrates including the seed coat, and wounded or infected root tissue.     

Effect of coffee pulp on Trichoderma spp. in Kenyan tea soils

Abstract

Six organic amendments and one soil sterilant (Basamid) were screened at different rates to a given amount of soil, for their efficiency to enhance the population of Trichoderma spp. Coffee pulp significantly (P = 0.01) enhanced the population of Trichoderma spp. in the soil compared to other amendments. The enhancement was rate‐dependent with 16 and 22 g carbon giving the optimum population. The Trichoderma species enhanced included T. koningii, T. harzianum and T. longibrachiatum. The implications of these results in relation to biological control of soil‐borne plant pathogens are discussed.     

基于EPG分析无翅型和有翅型柑橘蚜虫的取食行为

为明确无翅型、有翅型柑橘蚜虫取食行为的差异,采用EPG技术对褐色橘蚜Toxoptera citricida(Kirkaldy)和棉蚜Aphis gossypii Glover的有翅型、无翅型成蚜在柑橘苗上的取食行为进行测定。结果表明,褐色橘蚜无翅型和有翅型的EPG均记录到7种取食波形,依次为非刺探波np、路径波A、B和C、电位下降波pd、韧皮部取食波E1和E2;棉蚜无翅型和有翅型的EPG记录到9种取食波形,除上述7种外,还包括木质部主动吸食波G和口针阻碍波F。褐色橘蚜有翅型和无翅型的np波持续时间为25.73 min和8.39 min,二者间差异显著;棉蚜有翅型的np波持续时间、刺探次数、C波次数分别为27.34 min、19.16次、20.21次,显著高于无翅型,而刺探总持续时间为332.66 min,显著低于无翅型。棉蚜的C波次数及总持续时间、刺探次数、pd波次数及总持续时间均显著高于褐色橘蚜,而E2波总持续时间及平均持续时间均显著小于褐色橘蚜。表明棉蚜无翅型比有翅型在柑橘上更容易取食,影响有翅型蚜虫取食的抗性因子可能位于柑橘表面;褐色橘蚜比棉蚜对柑橘的适应性更强。