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 vari
eties. 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.
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.
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 .
This research carried out in the orchards of the Stamo area province of Lattakia citrus
during the years 2014-2015, and the results of the study showed that the insect black
cortical one generation per year with a second partial generation during t
he summer. Under
the insect overwintering nymph stage in the second age is the most able to withstand the
low-temperature phase in the winter. Mermaid back age-second activity in the beginning of
spring to complete their life cycle where the female young appear in early April on each of
the branches and leaves, to show adult females with the beginning of the month of May
and starts the eggs to hatch in the middle of this month and will continue until the month of
July. The study found that the nymph stage second phase age is the most common during
the season at each of the branches and leaves. Observed the death of large numbers of the
insect in the phasic nymph third age and female fledgling stage, which evolved during the
same season, as the study of the distribution and the spread of the different phases of the
insect on the plant parts showed that the branches were more injury than securities with
higher than moral in the population density of the presence of eccentric nymph and adult
stages the branches compared with the leaves.
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 be
an 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 study was conducted in 2011 on 6-years-old citrus trees "Washington navel
141". It contained four treatments with three replicates for each treatment. The results
showed that:
The wastewater treatments showed superiority on the control in the
number of
vegetative growth and its length.
The number of inflorescence buds, was increased in the second treatment (irrigation
with 50% treated wastewater +50% normal water) (5. 37) which dominated the other
treatments.
The weight of fruit was affected by treated wastewater irrigation. Second treatment
(irrigation with 50%treated wastewater+50 % normal water) was better than the control
treatment. It was increased by (308. 3 g) compared to (259. 5 g) for the control treatment.
Fruit yield production per tree, was increased by second treatment (irrigation with
50% treated wastewater+50 % normal water) (28. 9kg) compared to (15. 3kg) for the
control.
Treated wastewater irrigation had positive effects in the quality of fruit
(Total sugar %), (T. S. S %) and the coefficient of maturity were increased in second and
third treatment compared to other treatments, while (T. A %) was decreased in all
wastewater treatments.
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 th
at 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.
Essential oils from peels of 6 citrus species were extracted. The species were
lemon (Citrus limon), orange (C. sinensis), grapefruit (C. paradisi), pomelo
(C. maxima), mandarin (C. reticulata) and bitter lemon (C. aurantium) using
hydro-distillat
ion (Clevenger type).
In general Gram-positive bacteria were more sensitive to the oil
extracts tested than Gram-negative bacteria, and P. aeruginosa was the most
sensitive within the Gram-negative group.
This research aimed to analyze the economic efficiency of marketing citrus
at the level of farmers in Syria in order to determine the marketing
performance and problems facing farmers. 380 farmer stratified samples were
taken from villages in both
Latakia and Tartous provinces according to the
contribution of each province in total country production. Results showed that
the marketing options available to farmers focused on two major methods: selfmarketing
in domestic markets, and production leasing to dealers, which both
accounted for 53.9% and 44.3% of total quantities marketed of the samples,
respectively.
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.
