Showing 3 results for Antagonist
M. Niknejad Kazempour, H. Pedramfar, S. A. Elahinia,
Volume 6, Issue 4 (1-2003)
Abstract
Antagonistic fungi Trichoderma harzianum (T1, from bean fields in Ahwaz, T2, from rice fields in Rasht), T. viride (T3 from bean fields in Shahriar, T4 from the collection in Plant Pest and Disease Institute, Tehran), Gliocladium virens (from bean fields in Kamal Abad, Karaj) and some fungicides (Benomyl, Carbendazim, Carboxin-Thiram, edifenphos and Zineb) were used to control sheath blight of rice incited by Rhizoctonia solani in vitro and under greenhouse conditions. The experiment was carried out in a completely randomized design with 12 treatments and four replications on Khazar rice cultivar in a soil infected by R. solani under greenhouse conditions. The results showed that the antagonistic fungi reduce sheath blight by 19.8 (T1), 21.5 (T2), 27.5 (T3), 19.6 (T4) and 18.5 (G1) percent. The antagonistic fungi in order of efficacy were T2>T3>T1>T4>G1. Benomyl, Carbendazim, Carboxin-thiram, Edifenphos and Zineb reduced disease by 32.5, 21.5, 12.8, 9.5 and 0 percent, respectively. Statistical analysis of data indicated that there existed no significant differences between T1, T3, T4, and G1 and Carbendazim fungicide to control disease however, the isolate T2 was as effective as Benomyl but Zineb had no effect on sheath blight.
F. Padasht Dehkaei, Sh. Mansouri Jajaei H. Rouhani,
Volume 8, Issue 1 (4-2004)
Abstract
One hundred and two microorganisms were isolated from 85 paddy soil samples of different locations in Guilan Province. Antagonistic effects of the microorganisms were tested against Gibberella fujikuroi on PDA medium. Twenty one microorganism isolates were selected for seed treatment in blotter test. Seven isolates that were satisfactorily effective in reducing pathogen colonies formed on seeds and seedlings were tested in controlling disease in a greenhouse experiment with split plot design. The antagonists were Bacillus subtilis, B. circulans, Bacillus sp., Trichoderma harzianum, T. virens (2 isolates), and F.23 (unidentified). Results showed that all antagonists effectively reduced the disease in sterilized soil compared with control but overall effectiveness of B. subtilis, T. harzianum, and T. virens was higher than others and lower than the fungicide treatment (thiophant methyl thiram W.P. 80% , 2g/L). It was found that when seeds were treated with antagonists prior to inoculation with the pathogen, the effectiveness of antagonists was significantly better than when they were applied after seed infection with the pathogen.
Sh. Kiani, Gh. Zadeh Dabagh, M.j Malakouti, A. Alizadeh ,
Volume 14, Issue 51 (4-2010)
Abstract
Gray mold, caused by Botrytis cinerea, is a serious disease of cut rose flowers (Rosa hybrida L.) in Iran. In order to elucidate the effects of different potassium and calcium levels in nutrient solution on susceptibility of cut rose flowers to gray mold, this experiment was carried out as factorial design in a randomized complete block with four replications at Safi Abad Agricultural Research center in 2008 for one year. In this experiment, rose plants were grown and subjected to three levels of potassium (1.0, 5.0 and 10.0 mM) in combination with two levels of calcium (1.6 and 4.8 mM) under hydroponic condition. Rose flowers from two consecutive harvesting periods were sprayed with the conidial suspension (104 spore/ml) of B. cinerea isolate. At the end of experiment the disease severity was recorded and analyzed. The results indicated that application of 10.0 mM K in the nutrient solution led to increasing rose disease severity to gray mold (30.4 % day-1) compared to 1.0 mM (24.8 % day-1) and 5.0 mM (26.2 % day-1) of K levels (P< 0.01). The increased susceptibility was associated with a decreased concentration of Ca in the rose petals. Correlation analysis revealed that susceptibility of rose flowers to gray mold significantly increased with K to sum cations ratio in the nutrient solution (r = 0.94*). The increase of Ca supply from 1.6 to 4.8 mM resulted in decline of disease severity from 29.6 to 24.6 % day-1 (P< 0.01). Therefore, balanced application of potassium and calcium (5.0 and 4.8 mM, respectively) is recommendable for preventing antagonistic effects between them and reducing of rose gray mold intensity under hydroponic conditions.
