Invasive Species Compendium

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Abstract Full Text

Pathogenicity and culture condition of different isolates of Alternaria alternata on Alternanthera philoxeroides.


Alternaria alternata is one of biocontrolling agents against Alternanthera philoxeroides. Pathogenicity of different A. alternata strains against A. philoxeroides was investigated by bioassay in laboratory, and the effects of different culture mediums, temperature and pH on colony growth and spore production of A. alternata were also determined to optimize the culture conditions. The results showed that: The pathogenicity of J-14 was the highest, followed by MS613, ZL500 and PEC strains, and the lowest for ML03 with 22.12% necrosis diameter as J-14. J-14 strain could well grow and produce spores on ADA medium, the colony diameter and spore production were 5.800 cm and 519. 374×106, respectively; 20-30°C and pH 6.5-8.5 were the proper temperature and pH value, with the best optimal 25°C and pH 7.5. It was concluded that J-14 strain was the most pathogenic to A. philoxeroides, ADA medium, 25°C and pH 7.5 were its optimal culture conditions, which provided important theoretical basis for developing it as biocontrolling agent against A. philoxeroides.