Survey of infection by Citrus tristeza virus on citrus variety in Tartous governorate Syria

A survey of infection by Citrus tristeza virus (CTV) was conducted during a visit to 14 citrus orchards in different regions in Tartous governorate in the Syrian Coast during the spring of 2012. We collected a total of /691/ samples of different varieties. Most of the samples were collected from plants with symptoms similar to symptoms caused by viral diseases (dwarfing, yellowing, mosaic, quick- decline, vein clearing, boat or spoon-shaped leaves), while other samples did not carry such symptoms due to the possible presence of latent infections. The samples were tested by using Tissue Blot immunoassay (TBIA). The Results showed that the rate of infection by CTV was 34.15% in the tested samples and the distribution of CTV in citrus orchards was by various ratios. The highest percentage of infection was detected in AL- Hamidiah (62.50%), whereas the lowest infection percentage detected was in Talin nursery (10%). Common orange Balady was the most infected by Citrus tristeza virus (41.43%). No virus infection was recorded in Mandalina samples.

A Study of the Status of Implementation & Mechanization of the Soil's Care Operations & its Effect on the Orange Trees

The research was carried out during the years 2010 and 2011. The results showed the following:  The soil's care operations are carried out in the modern and middle old orange fields and aren't carried out in the old fields ( more than 30 years). The operations are embodied in the cultivating operation (facial plowing). The plows are used only in the modern fields to prepare the seed bed for planting some plants (agronomists) between the trees classes.  The used plows were effected differently on the orange trees according to plowing depth and machine sorts. By using the disk harrows with (8) cm depth appeared some roots on the soil's surface. The trees roots were uprooted and cut up by using the chisel plow with (20) cm depth and by using the mould board plough with (30) cm depth, but the effect was so clear by using the mould board plough, that the most of the roots were hurt.

Effect Citrus trestiza virus infection in Growth of Balady common orange and Satsuma trees grafted on sour orange

Effect of Citrus trestiza virus (CTV) in Growth of Balady common orange and Satsuma trees grafted on sour orange Rootstock in Hraisoon during 2013 was studied. The results showed that of infection by CTV caused deformation of shaped leaves, boat or spoon-shaped leaves. The symptoms was greater in Satsuma from Balady common orange trees. Also leaf size average of Balady common orange trees reduced from 15.58 cm2 in healthy trees to 11.82 cm2 in infection trees as percentage 24.13, and from 19.64 cm2 in healthy Satsuma trees to 12.38 cm2 in infection trees as percentage 36.97. and length average of spring, summery and autumnal fresh foliages growths was reduced from 20.98 cm, 14.62 cm, 12.17cm in healthy Balady common orange trees to18.75cm, 12.52cm, 9.32 cm in infection trees respectively. Also it reduced from 18.78 cm, 14.56 cm, 10.06 cm in healthy Satsuma trees to 13.78 cm, 9.34 cm, 6.03 cm in infection trees respectively, the CTV had no significant effect on Trunk circumference in both varieties.

Estimation of Leaves Toleration "Some varieties of Citrus " For High Temperature Stress

The experiment was done within -2014 in plant physiology lab.of agriculture faculty of Tishreen University for estimation of high temperature stress toleration of citrus leaves in three varietis(Citrus Unshiu , Meyer Lemon,Citrus SinensisWashington). Many random samples of leaves were gathered from the foliage of the examined categories whereas tha average of the taken leaves was 200 from the whole sides for each one tree from the branches which are one year old . which were put for limited duration in a water bath about many different degrees of temperature then they were put in water and then in a solution of HCL acid . Many references were studied of containing :non spotting on leaves ,which means they are un harmed,simple spotting,the spotting of more than half of the leaves area,the perfect leaves spotting. Studied temperature were as the following :40-50-60-70-80.Each one of this mentiond temperature,40 leaves were used .The statistics analys were done with the way of Genstat 12,for the comparison between averages for the sake of calculating the least significant difference at the guidance level :5% . Studies showed that Satsuma leaves are the most toleration for high temperature,next Citrus SinensisWashington is less than Satsuma.At last Meyer Lemon was the least .

Identification of some species of aphids deployed in bean fields and citrus orchards in Latakia and the possibility of its transfer of local isolate of Cucumber mosaic virus

The research aims to Identify some species of aphids on plant families, and test the possibility of transfer to the local isolate of Cucumber mosaic virus. Two species of aphids in bean fields and citrus orchards have been defined, namely: Black bean aphid Aphis fabae and Cotton aphid Aphis gossypii, respectively, depending on the specialized classification keys. The infection proved vital feedback and testing the function using plants: Nicotiana tabacum and Chenopodium quinoa transfer each of the A. fabae and A. gossypii local isolate of Cucumber mosaic virus.

The Effect of different media in some properties of Fusarium spp. isolates which cause wilt and root rot in citrus seedling

Fusarium oxysporum and F. solani, causal agents of wilt and rot root in citrus seedling are variable pathogens. This study was conducted on the effect of different media in characters, sporulation, and spore germination of fusarium spp. Isolates that were isolated from seed and seedling of citrus. The data revealed that the maximum mycelial growth was obtained in most isolates on Potato Sucrose agar for F. oxysporum and F. solani, followed by Potato Dextrose agar for F. oxysporum, and by Czapek’sDox agar for F. solani. The maximum sporulation was recorded in Potato Sucrose agar medium followed byCzapek’sDox agar . The study also showed that Potato Dextrose agar was the best for germination of spores.

Natural Occurrence of Entomopathogenic Nematodes (EPNs) in Citrus Orchards in Lattakia Governorate, Syria

This research was conducted in laboratory of Nematology in the Center of Scientific Agricultural Research in Lattakia, to detection of Entomopathogenic Nematodes (EPNs) in Citrus Orchards soils in Lattakia governorate. A total of 66 composite soil samples were collected from Citrus orchards during (2016- 2017). Entomopathogenic nematodes (EPNs) were recovered from soil samples by the insect baiting technique, using seventh instar larvae of the Greater wax moth Galleria mellonella (Lepidoptera: Pyralidae). Infective juveniles (IJs) were collected from G. mellonella cadavers using the method of White (1927). EPN isolates were identified based on morphometric methods. Eight isolates were identified as Heterorhabditis bacteriophora Poinar 1976 (Ord. Rhabditida: Fam. Heterorhabditidae) . Positive soil samples ratio was 12.12% of total samples, where EPNs isolates were extracted from regions (Al-Bassa, Al-Magreet, Al-Shamia, Gio, Al-Kharnoba, Al-Sorsokia, Fideo, Borj Al-Qasab)0 The soil textures of the EPNs positive samples were (sandy loam, silt loam, loamy sand, loamy clay sand, clay) with ( pH 6.34- :0.5) and (1.99- 4.82) g\100g organic content. The electrical conductivity of the nematode positive soils varied from 0.33 to 0.82 ds/m.