© Benaki Phytopathological Institute
Karajeh
36
2013).
The present study was conducted to in-
vestigate and compare the effects of
S. cer-
eviciae
, H
2
O
2
and oxamyl on growth and
M.
javanica
management of tomato under field
conditions.
Materials and Methods
A root-knot nematode-infested field pre-
viously planted with tomato was select-
ed for conducting a field experiment from
mid-February to mid-July 2013, which is the
main tomato growing season in Karak Val-
ley region (about 200mm annual rainfall,
clay loam soil, ca. 200m above sea level) in
Karak Province of Jordan, which is a drip-irri-
gated agricultural area. The field population
of RKN was identified as
M. javanica
by ob-
serving the perineal patterns of females and
measuring the length of second-stage juve-
niles (Barker
et al
., 1985). Species identifica-
tion was confirmed by
Meloidogyne
species-
specific sequence-characterized amplified
region-polymerase chain reaction (SCAR-
PCR) test (Karajeh, 2004).
Three-week-old tomato seedlings about
10cm tall of cv. Asala (Eastern Company,
Amman, Jordan) were transplanted into
black plastic mulch covered rows with 80cm
width and 150cm spacing between rows.
One week after transplanting, the following
treatments were applied into a randomized
complete block design and each treatment
(7 plants per plot) was replicated five times:
1.
Saccharomyces cerevisiae
(ready-made
yeast, Yeast Industries Company, Jordan,
1X10
8
CFU/g) was added to the rhizo-
spheric soil at the rate of 10g/plant.
2. Hydrogen peroxide (technical grade) was
added to the rhizospheric soil at 10mM
concentration.
3. Oxamyl (Vydate
®
L, 24% v/v, Dupont, Del-
aware, U.S.A.) was added as soil drench
into the rhizospheric soil at 3.5 L a.i./ha
within its manufacture’s recommended
application range (2.88-4.80 L a.i./ha) for
vegetables.
4. Untreated (control): plants were irrigated
with water only.
The treatments were repeated twice af-
ter two and four week intervals from the first
application. Traditional agricultural practices
(drip irrigation, weeding, air-borne pest con-
trol and fruit harvesting) were carried out
according to technical recommendations
in tomato cultivation (Werner, 1981). For the
determination of chlorophyll content, fresh
leaf samples (about 0.5 g) were immersed
after grinding in 5 ml of 100% acetone for 2
min to extract pigments. The absorbance of
extracts was measured at 645 and 663 nm
using the ultra-violet light–spectrophotom-
eter. The amount of total chlorophyll (chlo-
rophyll a + chlorophyll b) was evaluated us-
ing a standard curve determined under the
same conditions (Hamid and Jawaid, 2009).
Fruit harvest started eight weeks after
transplanting. Total tomato yield per treat-
ment was recorded during the growing sea-
son. At the end of the experiment, the plants
were up-rooted. Shoot and root dry weights
were recorded. Root galling index was eval-
uated according to the 0–5 scale: 0: no gall-
ing, 1: 1–2, 2: 3–10, 3: 11–30, 4: 31–100 and 5
over 100 galls (Taylor and Sasser, 1978). Ran-
dom root samples (five samples per treat-
ment) were selected for measuring root to-
tal phenol content and stored in a deep
freezer until use. The amount of total pheno-
lics in roots was determined with the Folin-
Ciocalteu reagent procedure (Maurya and
Singh, 2010). Gallic acid was used as a stan-
dard and total phenolics were expressed as
mg/g gallic acid equivalents. Representative
rhizospheric soils were collected from each
treatment for nematode extraction using
the Baermann tray method (Whitehead and
Hemming, 1965) to estimate the final nema-
tode population number.
Statistical analysis
Data were analyzed statistically using
general linear model (GLM) procedure (SPSS
software version 11.5; SPSS Inc., Chicago,
USA). Least significance difference (LSD) test
was used for mean separation at the 0.05
probability level.
