The influence of the two substrates tested on 18 isolates of Fusarium oxysporum f. sp. albedinis (Foa) was studied in order to compare the fungus behaviour on Casein and Glucose. It has shown that there is a mycelia growth of 63.63 % using casein, compared to 36.36 % using the Glucose. It has also been observed that the isolate "Foa Mtl 8" has shown a superior growth compared with the other isolates on liquid and solid casein medium, with a weight of 3 g, and it has completely covered the Petri dishes in first (in 6 days). On the same isolate, the detection of proteolytic activity by measuring the clarification diameters was most significant (4.2 cm diameter). On these criteria we had been based in order to select the isolate "Foa Mtl 8" for the determination of proteolytic activity. The colorimetric protein assay was performed by the method of Folin and Ciocalteu at different initial pH (4, 6 and 8). It had also shown that the isolate "Foa Mtl 8" produce a protease in pH range of 7.1 to 7.8.

Crown rust caused by Puccinia coronata f.sp. avenae is the most damaging disease on oat. This work analyzed the effects of temperature and illumination regime during different time of incubation on both spore germination and germ tube growth, using both analysis of variance (ANOVA) and response surface methodology (RSM). This study reveals that the maximum of germination approached 95% under dark conditions at 20°C. Similarly, the maximum germ tube length was 125±23 µm under dark conditions at the same temperature after 18 h. Both spore germination and germ tube growth were observed over a wider temperature range of 5 to 30°C. The darkness conditions seem to enhance significantly (P < 0.05) both the germination and germ tube growth. After 4 h of incubation, germination was significantly higher under darkness regime at 15, 20 and 25°C than under light conditions. The effect of darkness conditions on germ tube growth paralleled its effect on germination. Furthermore, the response surface methodology (RSM) was applied to determine the optimal conditions of temperature, time and illuminations conditions for both the germination process and germ tube growth of urediospores for P. coronata f.sp. coronata. Values for the optimal germination and germ tube growth were 20°C and 8 h under darkness conditions. Moreover, urediospores of P. coronata f.sp. coronata germination and germ tube growth had followed a quadratic response function on temperature (R² = 0.94 and 0.97). On the other hand, the experimental values were in good agreement with the predicted ones and the model was highly significant with the correlation coefficient R being 0.97 and 0.98, respectively for germination and germ tube growth.

Tomato (Lycopersicon esculentum) is one of the most widely grown vegetables in the world. There is a growing concern in recent years, both in developed and developing countries, about the use of hazardous fungicides for controlling plant diseases. The in vitro effect of two fungicides commonly used in Algeria namely Trifidan and Antracol (propineb) on the growth of three pathogenic fungi of tomato, Fusarium oxysporum f.sp. radicis-lycopersici, Fusarium commune and Fusarium redolens was investigated to determine the effectiveness of the fungicides in reducing fungi growth. Each fungicide was assayed at 0, 100, 200, 400 and 500 mg L -1 rate in Potato Dextrose Broth (PDB) and incubated at 28°C for seven days. Data were collected on the mycelia weights of the fungi under each treatment. Mycelia weights of the three fungi were significantly reduced at 100 mg L -1 by the two fungicides under antracol treatment F. redolens and F. commune and a significant reduction was observed at 400 and 500 mgL -1 . Application of Trifidan, significantly decrease in mycelia weight of F. oxysporum f. sp. radicis-lycopersici and F. commune irrespective of the rate applied. F. redolens was completely inhibited by Trifidan, and its inhibition started at 100 mg L -1 .

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