Effect of Different Concentrations of Spore and Dew Periods on pathogenicity of Fusarium oxysporum and Alternaria alternata in Biocontrol Control of Russian Knapweed (Acroptilon repens)

Subject Areas : Semi Annual Journal of Weed Ecology

niloufar moaven ¹ , Reza ghorbani ² , Roya Rezaiean ³

1 - دانش آموخته کارشناسی ارشد اگرواکولوژی، دانشگاه آزاد اسلامی واحد مشهد
2 - استاد دانشکده کشاورزی دانشگاه فردوسی مشهد
3 - استادیار گروه زراعت و اصلاح نباتات دانشگاه آزاد اسلامی واحد مشهد

Received: 2013-10-29 Accepted : 2014-11-02 Published : 2015-08-23

Keywords:

Abstract :

Russian knapweed (Acroptilon repens) is an invasive weed with high competition ability and one of the most important problematic weeds in the world. In order to evaluate Fusarium oxysporum and Alternaria alternata isolated from Russian knapweed for biological control of this weed and determine the best concentration of spore suspension and the effect of dew periods, two experiments were carried out during 2011-2012, using completely randomized designs with 4 replications. To determine the best concentration of spore suspension, Different concentrations of spore suspension (104, 105, 106, 107 spores ml-1) were considered in the first experiment. In the second experiment, the effect of dew periods (3, 6, 12, 18, 24, 48 hours) was studied. The results indicated that pathogenicity of both fungi was increased through increasing spore density and length of dew period. Plus, the concentration of 107 spores of Fusarium oxysporum and Alternaria alternata with 48 hours dew reduced Russian knapweed dry weight by 72% and 68%, respectively. Also, area under the disease progress curve rose up to 73% and 68% respectively.