الفهرس 
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Abstract
The results of soil analysis show that the soil texture of the samples collected from different sites of Minia governorate were almost similar, and were all clay soil with different proportions of sand. The moisture contents of the soil samples from wheat and maize fields analyzed varied between 3.4% and 26% cultivated with wheat and 4% to 33.3% cultivated with maize. The amounts of total soluble salts varied between 0.1 % to 0.24% in wheat fields and 0.07% to 0.3% in maize fields. The results of pH values varied between 6.15 - 7.96 being mostly on the alkaline side with few sites slightly acidic. The organic matter contents were mostly poor to moderate varying between 0.3 9% - 2.22% O.M.C.
2- Twenty eight fungal species were isolated from wheat belonging to 18 genera and that 13 species were isolated from maize belonging to 9 genera. These fungal species were isolated on four different media (PDA, Malt-extract agar, Czapek’s-Dox medium and V-8 medium) using two methods of isolations which are the dilution plate method and the Warcup method.
3- Aspergillus was the most dominant in both rhizospheric and nonnrhizospheric soils. Aspergillus was represented by 4 species which were; A.niger, A. terreus, A.flavus and A. ustus. Mucor, came next to Aspergillus and was represented by one species, Mracemosus. Penicillium came third and was represented by P.chrysogenum, Ppurpurogenum and Prubrum. Other fungal species isolated represented very low percentages of the total count except Drechslera halodes which flourished in the rhizosphere ·soil of maize more than in the neighboring root-free soil, whereas, Trichoderma harzianum flourished in both Soil habitats during Sept. and Paceilomyces lilacinus appeared in root-free soil only in Sept, in the case of maize on PDA medium.
4- Aspergillus also occupied the first rank and was represented as before by A.niger, A.flavus, A. terre us and A. ustus. Mucor racemosus also came second in wheat after Aspergillus. Penicillium came third and was represented by the three species, Pchrysogenum, Ppurpurogenum and Prubrum. Fusarium represented by F. oxysporum and F. moniliformae, in the case of wheat on PDA medium.
5- Aspergillus showed the highest percentages of isolation in case of maize. va
JvIucor racemosus_ came also next to Aspergillus, but with lower counts and so
Penicillium came third. Drechslera halodes was also isolated during both
months and T.harzianum & Paceilomyces lilacinus were isolated in Sept, on 1~
malt-extract medium. fo
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6- Higher isolations of Aspergillus were noticed, but less than that of maize, ol
Mucor racemosus also came next, followed by Alternaria alternata then Penicillium came in the fourth place represented by the three spp, Chrysogenum, purpurogenum and P.rubrum, in case of wheat on malt-extract
medium.
7- Aspergillus isolations were in the level observed using PDA medium. Onl~ three species were isolated, A.niger, A.jlavus and A.terreus. Mucor racemosus came 2nd to Aspergillus. Penicillium came the third and ’was represented by two species chrys2genum and Ppurpurogunum. Other fungi were of minor presence, in the case of maize on Czapek’s medium.
8- Aspergillus percentage in the total count was the highest compared to other genera and A.jlavus was the highest followed by A.niger then A.terreus, Mucor racemosus followed Aspergillus and was higher in root-free soil than the rhizosphere. Penicillium came next to Mucor which flourished more in the rhizosphere followed by Alternaria and other fungi were of minor presence, in the case of wheat on Czapek’s medium.
9- Trichoderma was represented by one species, T. harzianum and its percentages of presence in the different soils were also very close to that recorded using different media, in both crops.
10- Occurrence of Pythium spp. in wheat and maize fields as determined by isolations on selective medium. Three Pythium spp. were isolated during this investigation and these were according to their dominance; P. ultimum var, ultimum, P. irregulare and P. oligandrum.
11- Pathogenicity tests done on wheat showed that, the following fungal species exhibited pathogenic potentialities against on wheat were; Emericella nidulans, Drechslera halodes, Fusarium moniliforme, Fusarium oxysporum, Cochliobolus luntus, Cochliobolus tuberculatus, Pythium ultimum.