广州地区6种野生蔬菜上的病原真菌记述

通过对广州地区规模种植的野生蔬菜秋葵Abelmoschus esculentus（L.）Moench、紫背天葵Gynura bicolor DC．、香麻叶Corchorus capsularis L．、黄花菜Hemerocallis citrina Baroni、四稜豆Psophocarpus tetragonolobus（L．）DC．、一点红Emilia sonchifolia（L．）DC等的病害进行调查及病原菌鉴定,明确了8种真菌病害,分别是秋葵链格孢叶斑病Alternaria malvae Roum.et Letendre、秋葵壳二胞叶斑病Ascochyta abelmoschi Harter、紫背天葵链格孢叶斑病Alternaria tenuissima（Fr）Wiltshire、紫背天葵棒孢叶斑病Corynespora cassiicola Berk．＆Curt．、香麻叶炭疽病Colletotrichum capsici（Syd．）Butl．＆Bisby、黄花菜炭疽病Colletotrichum gloeosporioides（Penzo）Sacc．、一点红壳针孢叶斑病Septoria lactucae Passerini和四棱豆小球腔叶斑病Leptosphaeria blumeri E.Muller,并对各病原真菌的形态进行了描述。除黄花菜炭疽病外,其它7个均为国内未报道的植物真菌新病害。     

Heading date and resistance to septoria tritici blotch in wheat not genetically associated

Nineteen cultivars, with large differences in heading date, were evaluated for their response to septoria tritici blotch in two experimental setups in Njoro, Kenya. Due to the more or less constant temperatures during the growing season and the overhead irrigation applied the epidemic conditions were similar over the whole observation period for the early and late cultivars. In experiment 1 the cultivars were assessed for disease severity at the same moment irrespective of the developmental stage, while in experiment 2 the cultivars were assessed at the same developmental stage. Measured at the same time, the disease severity was highest in the early maturing cultivars and lowest in the late maturing cultivars (r = –0.78). When assessed at the same development stage the disease build up was independent of heading date (r = –0.10) but strongly dependent on resistance level. There were no indications that early heading cultivars were more susceptible than late heading cultivars. This revised version was published online in July 2006 with corrections to the Cover Date.     

Microscopic analysis of the effect of azoxystrobin treatments on Mycosphaerella graminicola infection using green fluorescent protein (GFP)‐expressing transformants

Green fluorescent protein (GFP)‐expressing transformants were used to investigate the effects of strobilurin fungicide azoxystrobin on Mycosphaerella graminicola infection. Azoxystrobin treatments (125 or 250 g AI ha^?1) were applied at various stages of the infection process under controlled conditions. GFP transformants showed conserved in vitro sensitivity to azoxystrobin and pathogenicity. Azoxystrobin controlled over 90% of M graminicola infections when applied before or during penetration of the pathogen (15% of the incubation phase). Azoxystrobin also impaired the growth of intercellular hyphae in M graminicola post‐penetration infection stages when applied at up to 50% of the incubation phase. Incubating infections observed in treated leaves were viable, but their growth was impaired and they did not induce necrosis under controlled conditions. Reduction by half of azoxystrobin dosage had little or no effect on azoxystrobin efficiency in controlling M graminicola. The contribution of post‐penetration fungistatic effect to azoxystrobin curative properties toward M graminicola in a field situation is discussed. © 2001 Society of Chemical Industry     

Quantitative PCR monitoring of the effect of azoxystrobin treatments on Mycosphaerella graminicola epidemics in the field

Quantitative PCR and visual monitoring of Mycosphaerella graminicola epidemics were performed to investigate the effect of curative and preventative applications of azoxystrobin in wheat field crops. A non-systemic protectant and a systemic curative fungicide, chlorothalonil and epoxiconazole, respectively, were used as references. PCR diagnosis detected leaf infection by M graminicola 3 weeks before symptom appearance, thereby allowing a clear distinction between curative and preventative treatments. When applied 1 week after the beginning of infection, azoxystrobin curative activity was intermediate between chlorothalonil (low effect) and epoxiconazole. When applied preventatively, none of the fungicides completely prevented leaf infection. There was some indication that azoxystrobin preventative treatments may delay fungal DNA increase more than epoxiconazole at the beginning of leaf infection. Both curative and preventative treatments increased the time lapse between the earliest PCR detection and the measurement of a 10% necrotic leaf area. Azoxystrobin only slightly decreased the speed of necrotic area increase compared with epoxiconazole. Hence, azoxystrobin activity toward M graminicola mainly resides in lengthening the time lapse between the earliest PCR detection and the measurement of a 10% necrotic leaf area. Information generated in this way is useful for optimal positioning of azoxystrobin treatments on M graminicola.     

Glasshouse and field evaluation of fungicides for the control of Septoria apiicola on celery

Propiconazole was more effective than either triadimenol or hexaconazole when applied after infection, for the control of Septoria apiicola on celery seedlings. In three out of four glasshouse experiments, 25 mg propiconazole I⁻¹ controlled S. apiicola completely when applied within 3 days after inoculation. Propiconazole and triadimenol at 5–15 mg l⁻¹ were also effective when applied 2 days after inoculation. Soil applications of a granular formulation of triadimenol (up to 20 mg per plant) controlled S. apiicola for 5 weeks on celery seedlings grown in pots and, in the field, granules at 100 mg per plant applied at planting were effective for 6 weeks. In two other field experiments the most effective treatments were foliar sprays of 25 mg propiconazole l⁻¹ applied every 7–10 days with or without the addition of anilazine or chlorothalonil.     

Disease Law and Forecasting of the Needle Blight ofPinus sylvestris var. mongolica

IntroductionNeedleblightofPinussylvcsIrisvarmongolicaisoneofthemaindiseaseonPinus3:VlvesIrlAvar.mongolicawhichisanativesPeciesinthearcabetWecnHulunbcirgrasslandandforest.Thisdiscaseisnotcdforscriousinfestation,fastspreadanddifficulttobecontrolled.Inthepas…     

A method to test wheat leaves for their reactions to inoculation with Septoria species

The construction and application is described of a polystyrol humidity box in which wheat leaves, while continuing to function as parts of living plants, can be tested for their reactions toSeptoria spp. in an atmosphere nearly saturated with water, as is required for successful infection. The method is simple, accurate ans inexpensive.Samenvatting Voor dit doel is een z.g. vochtdoos geconstrueerd (Fig. 1A). Het te toetsen blad wordt daar doorheen geleid en in de doos geïnoculeerd met een druppel conidiën-suspensie van de schimmel. Onder het blad staat wat water in de doos (Fig. 1B). Na afsluiting ontstaat in de doos de hoge luchtvochtigheid van bijna 100% die nodig is voor de infectie. Dit wordt op deze wijze eenvoudig en goedkoop gerealiseerd. De bladeren die zo worden getoetst blijven onbeschadigd functioneren aan de plant. Na enkele dagen kan de doos worden geopend en kan de symptoom-ontwikkeling worden afgewacht en gevolgd (Fig. 3A, 3B en 4). De methode leent zich voor nauwkeurig werk en vereist zeer weinig infectiemateriaal. De Technische en Fysische Dienst voor de Landbouw (TFDL), Wageningen, ontwierp en construeerde een statief voor het gebruik van de vochtdozen in serie (Fig. 2).     

Variations in pathogenicity patterns ofMycosphaerella graminicola withinTriticum spp. in Israel

Summary Pathogenicity patterns of 42Mycosphaerella graminicola (Septoria tritici) isolates secured from the major wheat growing regions in Israel, were assessed on seedlings of 16 bread and durum wheats. The spring bread wheat cultivar Titan (CI12615), the winter bread wheats Bezostaya 1, Kavkaz, NE7060 and the durum wheats Nursit 163 and Zenati Bouteille, all exhibited a high level of resistance. Significant cultivar × isolate interactions were recorded for isolates from the different regions in relation to the response of the 16 cultivars organized in 6 reponse classes to the test isolate ISR8036. Number of genes for resistance in the 16 cultivars was estimated, based on the assumption of a gene-for-gene relationship. Twelve complementary genes were hypothesized in the 42M. graminicola isolates × 16 wheat cultivars matrix. There was considerable variation in virulence frequencies between regions and between locations within the same region. The overall frequency of Bezostaya-Kavkaz virulence was low throughout the country (5–7%). The frequency of designated hypothesized virulence genes VST OLAF, VST COLOTANA, VST IAS 20 in Israel, was high in most locations. The reported analytical approach enables the identification of virulence hot-spots and assists in designing breeding for resistance strategies.     

The Inheritance of Resistance to Septoria Glume Blotch II. The Wild Wheat Species Aegilops speltoides

The inheritance of resistance in the wild wheat species Ae. speltoides L. to Septoria glume blotch (Septoria nodorum Berk.) was investigated. It was characterized by two parameters measured on detached leaves, namely lesion size (LS) and length of latent period (LP), and by the severity of the disease under field conditions (DS). The genetic analysis was based on the F₁ and F₂ generations of a 4 × 4 diallel cross between four Ae. speltoides accessions showing differential resistance to the pathogen. The three parameters of resistance were highly correlated. Considerable heterosis for resistance was found for each of the parameters in most of the diallel combinations. The estimates of broad-sense heritability were moderately high (0.50 — LS, 0.60 — LP, 0.52 — DS), while the estimates of narrow-sense heritability were low (0.16 for LS, 0.20 for LP, 0.25 for DS). There were no indications for genie interaction. It is suggested that the resistance is controlled by at least two genes with over-dominance of the alleles for higher resistance. Highly resistant Ae. speltoides accessions are a potential source of germplasm for improving the resistance of cultivated wheats to Septoria glume blotch. The possibility of using dominant alleles for resistance in hybrid cultivars is discussed.     

两种樟子松针叶病害的病原菌

1989年在中蒙边境樟子松林区大面积发生樟子松针桔痛，该痛危害严重．故笔者于19q4年～1996年对该痛原进行了分离培养．经鉴定引起该病害的痛原菌为偃松壳针孢(SeptoriapinitmmilaeSawada)和松走褥盘抱(Dothistroma pini Hulbary)．偃松壳针抱的分生孢干器球形，