فهرست مطالب شعله کاظمی

Early blight caused by Alternaria species is one of the most important tomato diseases in the world. The disease has been reported from most areas in Iran with up to 90% infection. This study was conducted to investigate the effect of nano-chitosan on the severity of the ‎disease and its use as a replacement‎ of the chemical fungicide, chlorothalonil.

Diseased tomato plants of fields and greenhouses of Fars province in southern Iran were sampled. Pathogens were isolated from diseased tissues, purified and identified by studying their morphological characteristics. The effect of nano-chitosan at three concentrations of three, five and seven grams per liter and the fungicide chlorothalonil were tested before and after inoculation of two pathogens. The disease severity indexes were measures in Sunseed and 16 cultivars of tomato under greenhouse conditions using a factorial experimental in completely randomized design with four replications. The data were analyzed with comparing the means.

The isolated pathogens were identified as A. solani and A. alternata. Results of the greenhouse experiment showed that A. solani was more aggressive than A. alternata and the cultivar 16 was more resistant to the disease. Nano-chitosan at 5 and 7 mg/ l significantly reduced disease severity indexes when use before pathogen inoculation, and at 7 mg/l when use after pathogen inoculation.

Nano-chitosan can be used as a bio-fungicide to replace chlorothalonil as a chemical fungicide for disease management.

Blight, caused by Mycosphaerella rabiei is the most important disease of chickpea in Iran. In order to find a method for the biological control of the disease, the inhibitory effect of 36 isolates of three species, Trichoderma harzianum, T. virens and T. atroviride, on a most virulent isolate of the pathogen, in hyperparasitism, dual culture, and production of volatile antibiotic compounds were investigated in vitro. Then the impact of the nine selected isolates of Trichoderma on the disease severity and growth of chickpea were tested in greenhouse. The results showed that the inhibitory ability of mycelium growth of the pathogen by isolates of T. harzianum, up to 52.42%, were greater than the others in plate assay. Also they had greater ability in reducing of disease severity in greenhouse condition. Some isolates of T. harzianum and T. atroviride had ability to promote the growth of chickpea in the presence of the pathogen with no significant difference as compared with the healthy control. It is the first report of the ability of these Trichoderma species in the biological control of this disease on chickpea.