Rob Reeder

Azolla filiculoides Lamarck (Azollaceae) (water fern), is an invasive floating macrophyte capable of rapid growth leading to the complete coverage of water surfaces. The North American weevil Stenopelmus rufinasus, Gyllenhal (Coleoptera: Curculionidae) is a biological control agent that has become naturalised in the UK. To determine the effects of the weevil on A. filiculoides in ‘semi-controlled’ conditions, weevils were introduced at four stocking densities into outdoor floating tanks containing A. filiculoides. The introduction of weevils at all densities resulted in a significant decline in percentage cover of A. filiculoides compared to the control. Increasing weevil stocking density resulted in a more rapid reduction in the area of green A. filiculoides. The highest stocking density of 400 weevils per m2 caused complete kill within a month of introduction. The UK summer provides conditions that are suitable for weevil reproduction and herbivory, and even the lowest stocking density of weevils tested (100 weevils per m2) can have a substantial impact on the surface cover of A. filiculoides. Although the weevil is effective in summer, augmentation is required annually for reliable control.

Comparative analyses were undertaken to characterize Xanthomonas campestris pv. musacearum, the causal agent of a wilt of enset and banana, and to assess its relatedness to other xanthomonads by fatty acid methyl esters, genomic fingerprinting using rep-PCR ...

Smilax china is a small perennial plant belonging to the Liliaceae frequently found in the warm temperate mountainous or hilly regions across eastern Asia. It is a commonly used Chinese herbal medicine. Leaf spot of S. china has been found to be a destructive disease in Tongcheng County, Hubei, China, where this plant is extensively cultivated. Symptoms were observed on infected leaves and fruits from 2006 to 2008 in a plantation established in 2002. Up to 70% of the plants in the areas surveyed showed severe leaf spot symptoms each year. Typical lesions observed were brown, circular or oval and 5–7 mm across. These enlarged and linked together, extending until entire leaves withered. Isolations were made onto potato dextrose agar (PDA) initially forming white colonies. After seven days on PDA, the colonies turned grey or brown, and by 12 days, the agar became blue-grey to dark green throughout. Sporulation was induced on cut filter paper following Zhang (2003). Conidiophores were fasciculated or single, straight or kneecurved, light brown with regular septa, and 20–58 × 3·6–5·5 μ m. Each conidium was obclavate, brown, 28–48 × 10–17 μ m, with 3–7 transverse and 0–3 longitudinal or oblique septa. The tops of some conidia developed into secondary conidiophores, which were cylindrical, hazel-coloured, and 5·5–22 × 2·5–5·2 μ m. The pathogen was identified as Alternaria longipes based on descriptions in Simmons (1981, 1999). Sequences of rDNA-ITS were obtained from three isolates, and comparisons with GenBank showed 100% similarity with A. longipes (AY751457). Pathogenicity tests were performed by spraying until runoff (200 mL/ plant) a conidial suspension (5 × 10 5 conidia/mL) containing 0·1% Tween20, onto upper and lower surfaces of 30 leaves of six one-year-old 20-cm tall plants. Plants were incubated with a 12 h photoperiod at 25 ° C and 90% relative humidity. Twelve days after inoculation, brown spots were observed on inoculated leaves, but no symptoms were seen on watertreated control plants. Koch’s postulates were fulfilled by re-isolating A. longipes from diseased leaves. Alternaria longipes is known in China to cause tobacco brown rot, but to our knowledge, this is the first report of A. longipes infecting S . china , and furthermore, no previous reports of a disease of S . china have been found.

... Presence of banana bacterial wilt (Xanthomonas campestris pv. musacearum) in Rwanda. RH Reeder 1,† ,; JB Muhinyuza 2 ,; O. Opolot 3 ,; V. Aritua 4 ,; J. Crozier 1 ,; J. Smith 5. Article first published online: 6 NOV 2007. DOI: 10.1111/j.1365-3059.2007.01640.x. Issue. ...

... Additional Information. How to Cite. Carter, BA, Reeder, R., Mgenzi, SR, Kinyua, ZM, Mbaka, JN, Doyle, K., Nakato, V., Mwangi, M., Beed, F., Aritua, V., Lewis Ivey, ML, Miller, SA and Smith, JJ (2010), Identification of Xanthomonas vasicola (formerly X. campestris pv. ...

Smilax china is a small perennial plant belonging to the Liliaceae frequently found in the warm temperate mountainous or hilly regions across eastern Asia. It is a commonly used Chinese herbal medicine. Leaf spot of S. china has been found to be a destructive disease in Tongcheng County, Hubei, China, where this plant is extensively cultivated. Symptoms were observed on infected leaves and fruits from 2006 to 2008 in a plantation established in 2002. Up to 70% of the plants in the areas surveyed showed severe leaf spot symptoms each year. Typical lesions observed were brown, circular or oval and 5–7 mm across. These enlarged and linked together, extending until entire leaves withered. Isolations were made onto potato dextrose agar (PDA) initially forming white colonies. After seven days on PDA, the colonies turned grey or brown, and by 12 days, the agar became blue-grey to dark green throughout. Sporulation was induced on cut filter paper following Zhang (2003). Conidiophores were fasciculated or single, straight or kneecurved, light brown with regular septa, and 20–58 × 3·6–5·5 μ m. Each conidium was obclavate, brown, 28–48 × 10–17 μ m, with 3–7 transverse and 0–3 longitudinal or oblique septa. The tops of some conidia developed into secondary conidiophores, which were cylindrical, hazel-coloured, and 5·5–22 × 2·5–5·2 μ m. The pathogen was identified as Alternaria longipes based on descriptions in Simmons (1981, 1999). Sequences of rDNA-ITS were obtained from three isolates, and comparisons with GenBank showed 100% similarity with A. longipes (AY751457). Pathogenicity tests were performed by spraying until runoff (200 mL/ plant) a conidial suspension (5 × 10 5 conidia/mL) containing 0·1% Tween20, onto upper and lower surfaces of 30 leaves of six one-year-old 20-cm tall plants. Plants were incubated with a 12 h photoperiod at 25 ° C and 90% relative humidity. Twelve days after inoculation, brown spots were observed on inoculated leaves, but no symptoms were seen on watertreated control plants. Koch’s postulates were fulfilled by re-isolating A. longipes from diseased leaves. Alternaria longipes is known in China to cause tobacco brown rot, but to our knowledge, this is the first report of A. longipes infecting S . china , and furthermore, no previous reports of a disease of S . china have been found.

... Additional Information. How to Cite. Carter, BA, Reeder, R., Mgenzi, SR, Kinyua, ZM, Mbaka, JN, Doyle, K., Nakato, V., Mwangi, M., Beed, F., Aritua, V., Lewis Ivey, ML, Miller, SA and Smith, JJ (2010), Identification of Xanthomonas vasicola (formerly X. campestris pv. ...

Comparative analyses were undertaken to characterize Xanthomonas campestris pv. musacearum, the causal agent of a wilt of enset and banana, and to assess its relatedness to other xanthomonads by fatty acid methyl esters, genomic fingerprinting using rep-PCR ...

... Presence of banana bacterial wilt (Xanthomonas campestris pv. musacearum) in Rwanda. RH Reeder 1,† ,; JB Muhinyuza 2 ,; O. Opolot 3 ,; V. Aritua 4 ,; J. Crozier 1 ,; J. Smith 5. Article first published online: 6 NOV 2007. DOI: 10.1111/j.1365-3059.2007.01640.x. Issue. ...