No abstract

Surveyed strawberry fields at three different districts (Abo Swar, EL-Kassasin and El-Manayef) in Ismailia Governorate during 2014-2016 growing seasons showed that 13 fungal species belonging to 13 genera were isolated from infected roots, runners and crowns segments of strawberry plants. The most frequent isolated fungi were; Macrophomina phaseolina (53.33%) and Colletotrichum acutatum (33.33%). These two pathogenic fungi were used in this study. Biological and chemical control experiments were conducted and significant differences in diseases incidence (DI%) and disease severity (DS%) were found among treatments of bioagents and chemical fungicides compared with control treatments. DI and DS percentages reached 0% when Bacillus subtilis or Rizolex were applied in plots of artificial infested soil with M. phaseolina and C. acutatum. Trichoderma harzianum occupied the second rank after B. subtilis, Rizolex (15 and 7.4% for DI) for M. phaseolina , (10 and 6.5% for DS)for C. acutatum, T. viride (16 and 16% for DI), (26 and 11% for DS) and Streptomyces canescens (20 and 21% for DI), (25 and 26% for DS), respectively. Moreover; Rizolex gave best results in pathogens control more than Topsin-M fungicide. In field experiment; the effect of soil disinfection using three treatments; two fumigants (Methyl bromide and Agrocelhone) and solar heating solarization applied on two strawberry cultivars (Festival and N-70) during 2015 and 2016 seasons were studied. Soil fumigation with Agrocelhone™ compound and Methyl bromide (MB) led to the best results for soil disinfection on both Festival and N70 Strawberry cultivars during two seasons. Percentage DI and DS of crown and root rot diseases occurred were (9.4, 9.0%) and (8.4, 7.5%) for both cultivars, respectively in 2015 it was very low (2.9, 3.0%) and (2.5 and 3.0%); respectively when applied again in 2016.

Pythium leak is a post-harvest disease of potato tubers manifested by a wet, spongy rot that can quickly lead to complete tuber decay.Two isolates of Pythium sp. from Salhia and Ismailia districts were isolated from naturally infected potato tubers. The morphological characters examined were dimensions of oogonia ,oospores , antheridia , hyphal swelling and oospores wall thickness. Oogonia were mostly terminal and the hyphal swelling were mostly intercalary in the two isolates. These morphological characters of Salhia and Ismailia isolates were in accordance with the reference data of Pythium ultimum var, ultimum. . Pathogencity tests of the two P.ultimum isolates of Salhia and Ismailia revealed that Ismailia isolate capable to cause higher incidence of infected tubers and the depth of internal rot was more than that in case of Salhia isolate. Cultivar reactions indicated that Diamant cultivar was the most susceptible to both P.ultimum isolates, however, Maradona and Baraka cultivars were the least susceptible ones. In the same time, Spunta , King Edward, Alpha ,Desiree and Drage showed moderately reactions . The optimum temperature for growth of both isolates of P.ultimumgrowth on PDA was 30 o C . The lowest growth was observed at 5 and 40 o C. Laboratory screening tests with four fungicides indicated that Previcure-N inhibited completely at 150 ppm.Accorrding to the available literature knowledge; this is the first report of infection with leak rot of potato tubers caused by P. ultimum var. ultimum in Egypt.

Rice straw bales could be used as a growing media for cultivation of vegetable crops instead of soil. The present study, which is considered the first in this respect in Egypt, aimed to evaluate the effect of using rice straw bales as a medium for cultivation of pepper on the disease infection by root pathogens. The cultivation of sweet pepper seedling cv.4408 F1 hybrid on rice straw bales was carried out in two locations: in El-Ismailia Governorate (Abo-Swear and El-Ferdan Districts), under plastic net greenhouse conditions during 7-10 May. 2007. In the first location, Abo-Swear, the disease incidence of root rot, wilt and root knot nematodes in sweet pepper plants grown in rice straw bales reached 1.1, 0.85 and 0.0% respectively. However, the corresponding figures for sweet pepper plants grown in natural soil under the same conditions were 14.8, 21.9 and 33.2%, respectively. The same trend was observed in the second location El-Ferdan district. Determination of pathogenic nematodes in rice straw bales and natural soil revealed the presence of 80 juvenile (J2) of Meloidogyne spp. and 120 juvenile (J2) of Tylenchorhynchus sp. per 250 g natural soil. However, the pathogenic nematodes were absent in rice straw bales. Isolation trials from naturally root-rotted and wilted pepper plants grown in natural soil and compacted rice straw bales under plastic net house conditions indicated that both Fusarium oxysporum Schlecht and Rhizoctonia solani kuhn were the most frequent isolated fungi. Other associated fungi belonging to the genera Pythium, Sclerotiom, Trichoderma and Rhizopus showed the lowest frequency. Pathogenicity of the most frequent isolated fungi was proved and showed that pepper plants were attacked by F. oxysporum and R. solani. Pepper grown in rice bales showed better growth and increased fruit number and weight compared with those grown in natural soil. The pH around the roots in straw bales ranged from 6.3 to 6.6 which pored to be a slightly acidic substrate. However, the pH around roots in the natural soil ranged from 7.4 to 8.5, alkaline soil. So, sowing in rice straw can solve the conditions of alkalinity and salinity in rhizosphere of pepper plants. On the other hand, plants grown in rice bales recorded lower E.C. (1.75 Mmohs cm-1) value around the roots compared with the natural soil (2.55 Mmohs cm-1) at the end of the experiment. On the basis of the above results, it could be recommended that using rice straw bales as a growing media in replacing naturally infested soil, can improve the production of pepper under greenhouse conditions for exportation. Also, avoiding the serious environmental air pollution called the "Black Cloud" when disposed about 5 million tons of rice straw every year by burning.

No abstract