الفهرس 
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Abstract
114 SUMMARY
6. SUMMARY
Citrus is one of the most important fruit crops in Egypt as
well as in many countries of the world. Citrus plantations are
widely distributed in Egypt for local consumption as well as for
exportation.
The obtained results from this work could be summarized
as follows:
1. Eleven fungal isolates were isolated from diseased Navel
orange fruits collected from Egyptian wholesale market,
different retail markets and from orchards of different
Governorates, i.e. Giza, Menofeia and Kaluobia. These fungi
were purified and identified as Geotrichum candidum,
Cladosporium herbarum, Thielaviopsis pavadoxa, Phomopsis
citri, Alternaria citri, Alternaria alternata, Nigrospora sp.,
Penicillium digitatum, P. italicum, Alternaria sp. and
Botryodiplodia theobromae.
2. All the isolated fungi proved to be pathogenic to Navel
orange fruits. Penicillium digitatum, P. italicum and B.
theobromae were the most pathogenic fungi. Meanwhile, G.
candidum and A. citri gave moderately infection. On the
other hand, Nigrospora sp., A. alternata, Phomopsis citri,
Thielaviopsis paradoxa and Cladosporium herbarum were
the least pathogenic ones.
3. Trichoderma hamatum, T. harzianum, T. legonarum and T
viride isolated were used for the biocontrol in vitro and in
vivo for the causals of fruit rots incited by A. cz.r.rz, B.
theobromae and G. candidum.
a. In vitro experiments:
The effect of culture filtrate of the bioagent fungi on growth
of the three pathogenic fungi demonstrated their growth was
affected to different degrees. The highest to c effect was
produced from one-week-old culture of T.viride, hamatum and
T harzianum isolates. The growth of the fungus candidum was
completely inhibited with the three tested conce trations (5. 10
and 20%), with exception of the culture filtrate 0 T. legonarum.
Also, the concentrations of 5 and 10% reduced the growth of A.
cirri to a large degree, while the concentration of 20% completely
inhibited the fungal growth. Culture filtrate of the tested
concentrations minimized the growth of B. theobroMae, especially
the culture filtrate of T hamatum, which gave the highest effect.
The same trend was observed by the two and three weeks
old culture filtrate, where G. candidum was suppressed by the
culture filtrate of T viride and T. hamatum. Alsol ,the reduction
in A. cirri growth was increased when the concentration of the
culture filtrate of T hamatum, T viride, followed by 7’,
legonarum and T harzianum was increased. The tested
concentrations of the tested bioagents exhibited Slight effect in
reducing the growth of B. theobromae.
b. In vivo experiment:
The effect of T harzianum and T. hamatum i olates and the
commercial products of Plant-guard (T harzianum and Rhizo-N
(B. subtilis) were studied against Navel orange it rots in vivo.
The percentages of fruit-rot and fruit-rot severity were
115 SUMMARY
significantly decreased in all treatments and the decrease was
increasedby increasing the bioagent concentration.Plant-Guard at
all the tested concentrations was the most effective in decreasing
and suppressing incidence and severity of fruit-rots caused by G.
candidum during 1999 season. The same effect was obtained
with spore suspension of T. hamatum, which gave the highest
effect in reducing decay caused by A. citri. Also, T harzianum
spore suspension followed by Rhizo-N and Plant-Guard were
more effective in controlling incidence and severity of fruit-rots
caused by B. theobromae.
Data of 2000 season exhibited, also, significant reduction
in both incidence and severity of fruit-rots caused by the tested
fungi. The three bioagent concentrations entirely suppressed the
decay caused by G. candidum, with exception of Plant-Guard at
1.5 ml/L, which decreased the infection to a low degree. Rhizo-
N, followed by Plant-Guard, T. hamatum and T. harzianum
greatly reduced the infection with A, Mil, At the same time, the
higher concentration of the tested bioagents exhibited clear
reduction to Navel orange fruit-rots.
4. The effect of the different concentrations of the tested
bioagents on the quality of Navel orange during 1999 and
2000 seasons showed that there was an increase in the
firmness of the treated fruits with the different concentrations
of the tested bioagents. Also, the same direction was
observed in case of total soluble solids and ascorbic acid in
inoculated fruits and treated with the three tested
concentrations of the tested bioagents. While Titratable
acidity exhibited the converse effect, which inoculated fruits
116 SUMMARY
with G. candidum, A. cirri and B. theobromae gave higher
level of acidity.
5. Exposing Navel orange fruits to UV light greatly reduced rot
development compared with unirradiated fruits. The efficacy
ofUV was increased by increasing UV wive length and
exposure time. Ultraviolet light at 365 run gave highest effect
than irradiation with 254 nm at all exposure times. In all
cases, the infection with the three tested fungi was suppressed
and/or decreased to different degrees compared with check
during seasons of 1999 and 2000.
6. The effect ofUV light on Navel orange quality during 1999
season showed that fruit firmness was increased with
increasing UV wave length and exposure time. At the same
time, the irradiated fruits gave high amounts ftotal soluble
solids and ascorbic acid compared with check. ’Meantime, the
lowest wave length ofUV increased TSS and ascorbic acid,
while UV at 365 run gave the lowest levels. On the contrary,
UV light minimized the Titratable acidity in the infected
fruits with the tested fungi compared with check.
During 2000 season the same effect was observed.
However, UV at 365 nm gave the highest ’evels of fruit
firmness. While, in case of total soluble solids and ascorbic
acid, irradiated fruits with 254 nm for 1, 3 and 5 minutes
exhibited the highest amounts than those exposed to UV at
365 nm. On the converse, exposing inoculated fruits with the
tested fungi to UV at 254 nm gave higher levels of titratable
acidity more than that exposed to UV at 365 nm, except
117 SUMMARY
inoculated fruits with A. citri and irradiated with 365 nm for
3 minutes, which showed the highest level of acidity.
7. Dipping Navel orange fruits in the preparations ofSOPP,
Kaligreen, ascorbic acid, salicylic acid and sorbic acid at 500,
1000 and 1500ppm before storage indicated that the
reduction in both fruit-rots infection and fruit-rots severity
caused by the tested fungi was increased compared with
check. During 1999 season, sorbic acid at 1000 and 1500ppm
was the most effective in decreasing both incidence and
severity of fruit-rots caused by G. candidum. On the other
hand, SOPP at l500ppm entirely inhibited the decay caused
by A. citri, while salicylic acid at 1000 and 1500ppm
exhibited higher effect in controlling the decay. Moreover, all
the tested chemical salts demonstrated slight effect in
reducing the decay caused by B. theobromae.
During 2000 season, Kaligreen, ascorbic acid and sorbic
acid each at l500ppm gave the best results in controlling G.
candidum and A. citri. While, incidence and severity of
infection caused by B. theobromae was completely
suppressed by dipping the fruits in SOPP at 1500ppm and
decreased to a large degree by dipping the fruits in salicylic
acid, ascorbic acid and Kaligreen at l500ppm.
8. Treating Navel orange fruits with different concentrations of
chemical salts after inoculation with the tested fungi
exhibited obvious increase in fruit firmness, total soluble
solids and ascorbic acid contents compared with untreated
fruits. Meantime, these contents were greatly increased in
inoculated fruits with the tested fungi and treated with SOPP
118 SUMMARY
and sorbic acid at 1500ppm. The amount of acidity was
decreased in the infected fruits treated with the different
concentrations of the tested chemical salts, and increased in
uninoculated and untreated ones.
The same trend was obtained during 2000 season,
wherever, firmness, total soluble solids and ascorbic acid
were increased in the inoculated fruits and treated with
different concentrations of chemical slats, while Titratable
acidity was decreased.
9. In vivo experiment, screening of six fungicides against the
three pathogenic fungi revealed that Eupare i was the most
effective fungicide on the growth of G. candidum, followed
by Bellkute, Tecto 45% and 2,4-D 35%, while Tecto 98%
and 2,4-D 40% were the least effective fungicides. Also,
Euparen and Bellkute were the most effective on A. citri,
followed by Tecto 45%, while Tecto 98% and 2,4-D were the
least effective in this respect. Tecto 45% was very effective
fungicide in reducing the mycelial growth of B. theobromae,
followed by Euparen, Tecto 98% and 2,4-D 35%, while
Bellkute gave the same effect at 600 ppm. 2,4-D 40% was the
least effective fungicide against the mycelial growth of B.
theobromae.
10.Euparen fungicide at 1000 and 1500 ppm was the most
effective fungicides, for controlling postharvest Navel orange
fruit-rots, which entirely inhibited the infection with G.
candidum and B. theobromae and also decreased incidence
and severity of fruit-rots caused by A. citri. Also, Bellkute
119 SUMMARY
fungicide at the highest concentration was effective in
decreasing the infection with the tested fungi.
During 2000 season, incidence and severity of fruit-rots
were decreased with increasing the fungicide concentration.
All the tested fungicides significantly reduced the decay
incidence. Tecto 98% and 2,4-D 35% each at 1000 and 1500
ppm completely suppressed the infection with G. candidum.
Euparen fungicide at 1500ppm entirely inhibited G.
candidum infection and was very effective against A. cirri
and B. theobromae. Belikute at 1000 and 1500 ppm caused
great effect against disease incidence and severity of fruitrots
caused by the three tested fungi. Tecto 98% gave
moderate effect in controlling A. citri and B. theobromae,
while 2,4-D 40% and Tecto 45% gave the least effect in
controlling the decay disease.
11. Treated and untreated Navel orange fruits with the tested
fungicides indicated that inoculated fruits with G. candidum
and treated with Euparen were firmer than that treated with
the other fungicides and untreated ones. Inoculated fruits
with A. cirri and treated with 2,4-D 35% were firmer
compared with control treatment. The same effect was
observed in inoculated fruits and treated with the different
concentrations of Tecto 45%.
The different concentrations of Euparen, followed by
Tecto 98% at 1500 ppm resulted in an obvious increase in
total soluble solids of the inoculated fruits with the tested
fungi compared with control treatment.
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121 SUMMARY
Concerning ascorbic acid, data revealed that ascorbic acid
content was comparatively higher in the inoculated fruits and
treated with the different concentrations of Bellkute. In
addition, inoculated fruits and treated with different
fungicides showed high values of titratable acidity, while
inoculated and untreated fruits gave the highest levels of
acidity. The same trend was obtained during 2000 season. In
this respect, fungicide treatments exhibited the highest levels
of firmness.
Total soluble solids and ascorbic acid showedalso higher
amount in the inoculated and fungicide treated fruits.
Meantime, Euparen at 1000 and l500pprti was the best
fungicide, which gave higher amounts. On the contrary,
acidity was decreased in the inoculated fruits and treated with
the tested fungicides compared with control treatment.
12. Dipping inoculated Navel orange fruits with the tested fungi
in two growth regulators, i.e. gibberellic acid, and ethrel,
respectively caused significant reduction in both incidence
and severity of fruit-rots compared with control treatments.
In addition, increasing the concentration of both materials
caused also gradual decrease in both incidence and severity
of the disease. Moreover, no great variation Was detected in
the effectiveness of both growth regulatory on the tested
fungi. However, both A. cirri and B. theobromac were more
affected than G. candidum.
All the tested growth regulators caused different degrees
of increase in the firmness, T.S.S. and Ascorbic acid
compared with control treatment. On the contrary, acidity of
the treated fruits was lower than that estimated in untreated
fruits.
13. Treating Navel orange fruits with sodium meta bisulfit
(Na2S205), sodium carbonate (NaC03) and hydrogen peroxide
(H202) after inoculation with any of G. candidum, A. dirt and
B. theobromae caused significant reduction in both incidence
and severity of fruit-rots compared with untreated fruits. In
addition, increasing the concentration of these materials
resulted in gradual decrease in the disease.
No significant differences were detected in the values of
incidence and severity of fruit-rots due to the infection with
the three tested fungi.
Low decrease in fruit firmness at 20 and 30 gIL of all
the tested chemicals, i.e. Na2S205, NaC03 and H202
compared with control treatment.
Meanwhile, at 40 giL low increase was recorded. T.S.S.
showed low decrease when the fruits treated with SO 2 at 20
giL and NaC03 and H202 at 20 and 30 giL compared with
control treatment. The estimated Ascorbic acid recorded
considerable increase compared with control treatment.
Opposite results were obtained in case of fruit acidity.
14. Data of suspend any of Tecto 45% and Bellkute in water of
different degrees of temperatures, i.e. 20, 40 and 50 0C
revealed that both fungicides were more effective in reducing
incidence and severity of fruit-rots at 40 then 500 C than at
200e compared with control treatment. In addition,
increasing the concentration of both fungicides caused
gradual decrease in the disease.
122 SUMMARY
The inoculated fungi recorded low differences in their
affect by the tested two fungicides, especially at 40 and 50°C
than at 20°C.
Great fluctuation in the firmness, T.S.S., Ascorbic acid
and fruit acidity was detected due to variation in the used
degrees of temperature and the fungicides. In this respect,
firmness and T.S.S. were increased in the inoculated fruit and
treated with the two fungicides (especially at 750 and 1250
ppm) at all the tested degrees of temperature. In the contrary,
fruit acidity of the treated fruits was slightly decreased at all
the tested degrees of temperature compared with control
treatment. On the other hand, both fungicides caused
considerable increase in Ascorbic acid at all the tested
fungicide concentrations and degrees of temperature compared
with untreated ones.
15. All the extracted mycotoxins by any of chloroform and ethyl
acetate as well as crude of the culture filtrate of the tested
fungi caused significant increase in percentages of both
necrotic fruits and necrotic areas compared with control
treatment. However, crude of the culture filtrate of 5 isolates
belonging to A. citri (isolates 1, 3, 4, 5 and 6) and one isolate
(No.1) belonging to B. theobromae failed to cause apparent
symptoms of necrosis in the injected fruits in blossom-end.
The same was observed when the mycotoxin of isolate No. 3
of A. cirri extracted with chloroform was injected in the
blossom-end of the fruits.
On the other hand, the percentages of necrotic fruits
reach 100% when all types of mycotoxins of G. candidum
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were injected in the blossom-end of the fruits. This
percentage was also observed when mycotoxin of some A.
citri isolates as well as the two isolates of B. theobromae
were used.
Fruits injected in the stem-end showed also different
percentages of necrotic fruits. However, injection through stemend
was of high deleterious effect than when injection occurred
through blossom-end.
The averages percentages of necrotic areas of the injected
fruits with the extracted mycotoxins as well as due to the use of
crude of the culture filtrate of the tested fungi were in the same
trend with the percentages of necrotic fruits.
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