Anthracnose of centipede grass caused by Colletotrichum caudatum

Anthracnose disease was found on centipede grass [Eremochloa ophiuroides (Munro) Hack.] planted as a ground cover on paddy field levees in Shiga Prefecture in 2004. The symptoms were ear blight, stalk blight, and leaf spots. The causal fungus was morphologically identified as Colletotrichum caudatum (Sacc.) Peck. This is the first report of centipede grass anthracnose caused by C. caudatum.     

Resistance in water yam (Dioscorea alata) cultivars in the French West Indies to anthracnose disease based on tissue culture-derived whole-plant assay

Reactions of 60 water yam ( Dioscorea alata ) cultivars to three isolates of the yam anthracnose fungal pathogen ( Colletotrichum gloeosporioides ) were evaluated using tissue culture-derived whole-plant assay. Three disease parameters: single score on a scale of 0–6 at the seventh day after inoculation (SD7); area under the disease progress curve (AUDPC); and disease progress rate ( R _d) were compared, and cultivars were classified into disease-response groups using a rank-sum method based on AUDPC scores for the two most virulent isolates. A wide range of variation in resistance of the D. alata cultivars, and significant effects of pathogen isolate and isolate–cultivar interactions, were observed for all disease parameters. The three disease parameters were positively correlated; however, four cultivars showed great dispersions from the regression lines for comparisons of SD7 with the multiple assessments based AUDPC and R _d. The 60 cultivars were separated into resistant ( n  = 12), moderately resistant ( n  = 19), moderately susceptible ( n  = 18) and susceptible ( n  = 11) groups. The potential of the tissue culture-derived whole-plant assay to resistance breeding programmes and further understanding of the yam anthracnose pathosystem is discussed.     

Biocontrol efficacy of Colletotrichum truncatum for hemp sesbania (Sesbania exaltata) is enhanced with unrefined corn oil and surfactant

In greenhouse and field experiments, an oil-in-water emulsion of unrefined corn oil and Silwet L-77 increased the biological weed control efficacy of Colletotrichum truncatum (Schw.) Andrus et Moore for control of the weed, hemp sesbania ( Sesbania exaltata [Raf.] Rydb. ex A.W. Hill). The surfactant – corn oil emulsion stimulated germination and appressoria formation in vivo and in vitro and delayed the need for dew. We hypothesize that the corn oil protected the conidia from desiccation during the dew-free period and the surfactant stimulated spore germination and appressoria formation. In field experiments conducted over 3 years, a single application of a 50% (v/v) unrefined corn oil tank mixture containing 0.2% (v/v) Silwet L-77 surfactant controlled hemp sesbania in soybeans an average of 95%. Aqueous fungal suspensions or adjuvants alone did not visually affect or control hemp sesbania. The soybean yields were significantly higher in the plots where weeds were effectively controlled. These results suggest that formulating C. truncatum in unrefined corn oil and surfactant greatly increases its infectivity and the biocontrol potential of this pathogen.     

The spore coat of the bean anthracnose fungus Colletotrichum lindemuthianum is required for adhesion, appressorium development and pathogenicity

The spores (conidia) of the bean anthracnose fungal pathogen, Colletotrichum lindemuthianum, adhere to the aerial parts of plants to initiate the infection process. In previous studies we have shown that the Colletotrichum spores are surrounded by a fibrillar spore coat, comprising several major glycoproteins. Previous evidence showed that a monoclonal antibody (UB20) that recognised these glycoproteins was able to inhibit adhesion of spores to a hydrophobic surface. In this paper we have further studied the role of the spore coat in adhesion, germination and fungal development by studying the effects of UB20 and protease treatment of spores. The latter treatment has previously been shown to remove the spore coat. Spores germinate on glass, polystyrene and water agar, however, appressoria only develop on glass or polystyrene, showing a requirement for a hard surface. Removal of the spore coat with protease inhibits adhesion at 30 min, before the secretion of ECM glycoproteins. Protease treatment also inhibits the development of appressoria and reduces pathogenicity on leaves. Incubation of spores with the MAb UB20 inhibits adhesion at 30 min, but does not affect appressorium formation or pathogenicity. The results suggest that an intact spore coat has two functions; it is required for adhesion to a hydrophobic surface and for the detection of a hard surface necessary for appressorium formation. We suggest that contact with a hard surface, rather than adhesion, is the key event leading to appressorium formation.     

Localized hemibiotrophy in Colletotrichum: cytological and molecular taxonomic similarities among C. destructivum, C. linicola and C. truncatum

The infection process of hemibiotrophic isolates of Colletotrichum linicola (from flax, Linum usitatissimum ) and C . truncatum (from broad bean, Vicia faba and lentil, Lens culinaris ) was studied by light microscopy. Host surfaces were penetrated directly leading to a symptomless, biotrophic phase characterized by the elaboration of large multilobed, multiseptate, vesicular primary hyphae that were restricted to the initially infected epidermal cells. Biotrophy lasted for the first 48 h of the host-pathogen interaction and was rapidly succeeded by a necrotrophic phase during which narrow, secondary hyphae invaded the surrounding leaf tissues and water-soaked spreading lesions with sporulating, monosetate acervuli were produced on infected host surfaces. Molecular taxonomic analysis of the nucleotide sequences of the amplified D2 and ITS-2 regions of rDNA revealed very close similarities (97–99%) between these isolates and those of C . destructivum obtained from cowpea ( Vigna unguiculata ) and lucerne ( Medicago sativa ), and also of C . truncatum obtained from pea ( Pisum sativum ). This association was consistent with results from a comparative assessment of some in-planta and in-vitro morphological and growth characteristics of these hemibiotrophic fungi. It was concluded that localized hemibiotrophy is an infection strategy utilized predominantly by a closely-related group of pathogens comprising C . destructivum , C . linicola and C. truncatum , and the formation of multilobed primary hyphae restricted to the first penetrated cell might therefore be a key taxonomic character which correlates consistently with ITS sequence data.     

江西南方板栗炭疽病菌侵染动态的研究

江西板栗炭疽病菌（Ｃｏｌｌｅｔｏｔｒｉｃｈｕｍ ｇｌｏｅｏｓｐｏｒｉｏｉｄｅｓ（Ｐｅｎｚ）Ｓａｃｃ．）于初花末期开始侵染雌花柱头，侵染高峰在盛花初期。病菌经柱头侵入后，首先定植于花柱，然后在花柱中潜伏或进一步蔓延至子房。病菌具有潜伏侵染现象，已展开叶片、托叶、枝梢皮层、花器（雄花序、雄蕊、花柱）、幼果、幼嫩总苞的针刺及坚果（果皮和涩皮）普遍潜伏带菌，以上结果系首次报道。     

三种热雾剂对橡胶树炭疽病大田防治试验

田间试验比较10%百菌清、20%氟硅唑·咪鲜胺、16%百菌清·咪鲜胺·三唑酮三种热雾剂对大田橡胶树炭疽病的防治试验结果,其中前两种处理防效(相对防效68.14%和66.31%)显著优于16%百菌清·咪鲜胺·三唑酮和对照处理。     

普通油茶对炭疽病抗性的病理学研究

普通油茶对炭疽病抗性的病理学研究张常青关键词普通油茶、油茶炭疽菌、抗病类型、孢子萌发与侵入由于油茶炭疽病菌（ＣｏｌｅｔｏｔｒｉｃｈｕｍｃａｍｅｌｉａｅＭａｓｓｅｅ）的危害，使普通油茶（ＣａｍｅｌｉａｏｌｅｉｆｅｌａＡｂｏｌ）大量落花落果，这是严重影响...     

油茶炭疽病的化学防治研究

本研究使用14种杀菌剂对油茶炭疽病进行了室内和田间的防治试验。结果表明，扑菌清、叶斑净和宝宁的效果较好，同时对杀菌剂在田间的施用方法也提出了建议。     

茉莉酸甲酯和磷酸氢二钾诱导柱花草对炭疽病的抗性

探究茉莉酸甲酯(Methyl Jasmonate,MeJA)和磷酸氢二钾(K2HPO4)诱导柱花草对炭疽病的抵抗作用。结果表明,二者浓度分别为0.001~0.1mg·mL-1和10~50mmol·L-1时,病情指数均显著降低(P0.05),最佳诱导浓度分别是0.001mg·mL-1和30mmol·L-1,诱导效果分别是64.84%和54.40%。0.001mg·mL-1MeJA处理组的过氧化物酶(POD)及多酚氧化酶(PPO)活性在48h达到最大值,显著高于对照组。30mmol·L-1 K2HPO4处理组的POD与PPO活性分别在48和24h达到最大值,显著高于对照组。两种诱抗剂处理的POD和PPO活性在接种早期增加了柱花草对炭疽菌的侵染的抵御能力,进而提高植株的抗病性。30mmol·L-1 K2HPO4处理组的过氧化氢酶(CAT)活性在48~72h内上升,显著高于对照组,而0.001mg·mL-1 MeJA处理组的CAT活性除72h显著低于对照组,其他时间点与对照组相差不大。说明在诱导柱花草抗病性方面,两种诱导抗性剂处理的诱抗效果与POD、PPO和CAT的酶活性的诱导的时间及程度有关。