Field Efficacy of 33.5% Oxine-copper SC against Leaf Spot Disease on Waxberry

Leaf spot disease seriously affects the yield and quality of waxberry, but there is no registration agent for prevention and control of the disease. The field trials showed that the control efficacy of 33.5% oxine-copper SC against leaf spot disease on waxberry reached above 74% when used at the dosage of 167.5-223.3 mg/kg. 33.5% Oxine-copper SC could be used to control leaf spot disease on waxberry.

Morphological and Molecular Identification of Curvularia geniculata Associated with Leaf Spot Disease of Banana in China

[Objectives]The paper was to identify the causal agent of leaf spot of banana in Hainnan,China.[Methods]Fungus isolates were isolated from the diseased tissues,and morphological characteristics of colony and spore were observed.Furthermore,phylogenetic analyses and pathogenicity test were conducted to confirm the pathogen.[Results]The fungus isolates from the diseased tissues was identified as Curvularia geniculata.[Conclusions]C.geniculata is a new pathogen causing leaf spot of banana in Hainan,China.This finding will help to broaden the distribution and host range of C.geniculata,indicating that it poses potential damage to banana in China.

Genomic Selection for Frogeye Leaf Spot Resistance in Soybean

Soybean frogeye leaf spot(FLS) disease is a global disease affecting soybean yield, especially in the soybean growing area of Heilongjiang Province. In order to realize genomic selection breeding for FLS resistance of soybean, least absolute shrinkage and selection operator(LASSO) regression and stepwise regression were combined, and a genomic selection model was established for 40 002 SNP markers covering soybean genome and relative lesion area of soybean FLS. As a result, 68 molecular markers controlling soybean FLS were detected accurately, and the phenotypic contribution rate of these markers reached 82.45%. In this study, a model was established, which could be used directly to evaluate the resistance of soybean FLS and to select excellent offspring. This research method could also provide ideas and methods for other plants to breeding in disease resistance.

Molecular Characterization,Morphology and Pathogenicity of Curvularia pseudobrachyspora,A New Causal Agent of Leaf Spot on Banana

[Objectives]The paper was to study molecular characterization,morphology and pathogenicity of Curvularia pseudobrachyspora,a new causal agent of leaf spot on banana.[Methods]Banana(Musa acuminate)leaves with streaks or long ellipse-shaped lesions were sampled in an orchard of Danzhou City,Hainan Province,China in 2021.Fungus isolates were isolated from the diseased tissues and further identified as C.pseudobrachyspora based on morphological characteristics of colony,conidiophore and spore,phylogenetic analyses of the ITS region,GAPDH and TEF-1αgenes.[Results]In the pathogenicity test,the fungus re-isolated from inoculated leaves with necrotic lesions was identified morphologically and molecularly,fulfilling Koch's postulates.[Conclusions]C.pseudobrachyspora is a new pathogen causing leaf spot of banana in China and the world.

Neofusicoccum parvum Causing Leaf Spot of Camellia drupifera in China

[Objectives]The study was to identify the causal agent of leaf spots of Camellia drupifera in Hainan Province,China.[Methods]Phylogenetic analyses,spore morphology and pathogenicity tests were adopted to identify the pathogen.[Results]The fungus was identified as Neofusicoccum parvum.The colonies were initially pale to white on PDA,with diffuse yellow pigment around the colonies in the agar after 5 d.After 10 d,the aerial mycelium became gray,and the substrate mycelium became black.Thirty days later,a large number of conidia were generated on OMA.Conidia were hyaline,nonseptate,and fusiform.The mean size of 100 conidia was(13.6-25.4)×(6.2-10.3)μm;the mean length/width ratio was(2.5±0.3)μm.[Conclusions]N.parvum was the causal agent of leaf spots of C.drupifera observed in Hainan Province,China.

Study on the Control Effect of Chinese Herbal Medicine Regulator on Leaf Spot Nematode Disease of Chloranthus spicatus

[Objectives]This study was conducted to investigate the control of Chinese herbal medicine regulators on leaf spot nematode disease,the main pest of Chloranthus spicatus(Thunb.)Makino.[Methods]C.spicatus plants infected with nematodes were irrigated with a Chinese herbal medicine regulator at two different concentrations,and the control effect on leaf spot nematode disease of the plant was studied by measuring the number of nematodes,the contents of chlorophyll,malondialdehyde,soluble sugar and free proline in the leaves of the plants in the soil.[Results]Compared with the control,the two concentrations of Chinese herbal medicine regulator significantly reduced the number of nematodes in the soil,increased the contents of chlorophyll(mainly chlorophyll a),soluble sugar and free proline in the leaves of C.spicatus,and decreased the content of malondialdehyde.It indicated that the Chinese herbal medicine regulator could effectively control the spread of nematodes and had certain effect on the recovery of C.spicatus plants.[Conclusions]The use of Chinese herbal medicine regulators is helpful to curb the occurrence of leaf spot nematode disease in C.spicatus by biological prevention and control means,and provides theoretical guidance for the development of the green industry of C.spicatus.

南天竹一种新的叶斑病病原菌的分离鉴定

南天竹(Nandina domestica)为小檗科南天竹属,常绿灌木,形态优雅,果实球形鲜红且经冬不落,是赏果观叶的园林绿化植物。南天竹具有重要的药用价值,有“镇咳止喘、兴奋神经、强壮身体”之效[1]。在生长过程中,南天竹叶片易受炭疽病(Colletotrichum)危害[2]。