Late blight disease of potato and tomato, caused by Phytophthora infestans, results in serious losses to Egyptian and global potato and tomato production. To understand the structure and dynamics of the Egyptian population of P. infestans, 205 isolates were collected from potato and tomato plants during three growing seasons in 2010–2012. The characterization was achieved by mating-type assay, metalaxyl sensitivity assay, and virulence pattern. Additionally, genotyping of 85 Egyptian isolates and 15 reference UK isolates was performed using 12 highly informative microsatellite (SSR) markers David E. L. Cooke and five effector (RxLR) genes. Mating-type testing showed that 58% (118 of 205) of the isolates belonged to mating type A1, 35% (71 isolates) to mating type A2, and the rest 8% (16 isolates) were self-fertile. The phenotype of metalaxyl response was represented as 45% resistant, 43% sensitive, and 12% as intermediate. Structure analysis grouped the 85 identified genotypes into two main clonal lineages. The first clonal lineage comprised 21 isolates belonging to A2 mating type and 8 self-fertile isolates. This clonal lineage was identified as Blue_13 or EU_13_A2. The second main clonal lineage comprised 55 isolates and was identified as EU_23_A1. A single isolate with a novel SSR genotype that formed a distinct genetic grouping was also identified. The effector sequencing showed good correspondence with the virulence data and highlighted differences in the presence and absence of loci as well as nucleotide polymorphism that affect gene function. This study indicated a changing population of P. infestans in Egypt and discusses the findings in the context of late blight management.

Wheat powdery mildew, caused by the biotrophic fungus Blumeria graminis (DC) E.O. Speer f. sp. tritici Em. Marchal, is one of the most severe foliar diseases attacking this crop, affecting wheat production under Mediterranean basin conditions through the last few years. Four bread wheat cultivars i.e.. Sakha-93, Gemmeiza-7, Gemmeiza-10, and Giza-160 as a check were evaluated to artificial inoculation of powdery mildew under field conditions. The tested wheat cultivars showed susceptible responses to powdery mildew with fluctuated values in 2010 and 2011 seasons. In 2010 season, the tested cultivars showed high levels of disease severity, ranged from 35 to 87 % (Gemmeiza-7 and Gemmeiza-10, respectively). While, in 2011 lower levels were recorded, from 6.00 up-to 15% (Sakha-93 and Gemmeiza-10, respectively). Area under disease progress curve (AUDPC) was correlated with disease severity during the two seasons. Also, the yield components, the thousand grain weight and the grain yield/m 2 were affected by disease severities with different values for each cultivar. High air temperature, wind speed and mild relative humidity played an important role in increasing powdery mildew infection level in 2010 season.

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Strawberry gray mold disease caused by Botrytis cinerea (Pers.) is one of the most critical diseases attacking strawberry fruits especially at the post-harvest stage. This study compared the effectiveness of two types of Chitosan, bioagent's filtrates and fungicides in controlling the gray mold of strawberry. The commercial and synthesized in vitro Chitosan were tested on radial growth of B.cinerea on PDA agar plates and on infected four fruits cultivars strawberry. The results showed that the two types of Chitosan were significantly decreased infection of B. cinerea especially on un-wounded fruits that have been treated by dipping method. Biological control agents were used as culture filtrates for control strawberry gray mold pathogen both on wounded and unwounded fruits, the disease incidence was inhibited significantly in comparing to control treatment. Chemical fungicides were also used in these trials for controlling the gray mold disease. The results obtained confirm the superiority of fungicides in controlling the disease in comparing the commercial and synthesized Chitosan well as biocontrol agents.