Effect of four fungicides on growth of Alternaria solani and Pyricularia oryzae fungi under laboratory conditions.

The effect of four fungicides i.e. Leader 45% EC (prochloraz), Mystic 25% EC (tebuconazole), Nativo75% WG (tebuconazole 25% + 50% trifloxystrobin) and Score 25% EC (difenoconazole) on growth of two important fungal pathogens (A. solani and P. oryzae), (TEBD) and rice blast disease (RBD). The results clearly indicated that A. solani fungus was the most frequently isolated fungus from tomato leaves and fruits with 68.26 and 62.35 FO, respectively and was isolated most frequently from leaves than fruits of tomato. On the hand P. oryzae fungus was the most frequently isolated from leaves and Panicle of rice crop with 50.00 and 54.28 FO, respectively. The present data showed that both fungi was varied in sensitivity between fungicides and between concentrations used. The effect of the tested fungicides on mycelial growth of A. solani fungus clearly indicated that Leader fungicide followed by score, Nativo and Mystic with IC50 values of 0.16, 0.18, 0.26 and 2.06 ppm, respectively. Also, the efficacy of these fungicides on P. oryzae growth with IC50 values were 0.02, 0.21, 0.28 and 0.40 for leader, Score, Nativo and Mystic, respectively.
Also, the fungicides affected on total carbohydrates, total lipids and total proteins in both fungi and these compounds were varied in this parameters. These results suggested that many researches needed to determine the sensitivity of both fungi to fungicides to avoid fungicide resistance by important fungal diseases and to the increase of tomato and rice yield by reduction of these diseases on crops.