EFFECT OF CERTAIN BIOLOGICAL METHODS
IN CONTROLLING ROOT KNOT NEMATODES
ON SUGAR BEET PLANTS
Rem abdallh Abd el ghalk
SUMMARY
Two field experiments were carried out during both 2006 and 2007 summer
seasons at Sakha Agriculture Research Station, Kafr El-Shiekh Governorate, to study
the effect of two herbicides (fluazifop-Pbutyl and butralin) alone or in combination
with one insecticide (malathion) on weeds characters, yield and yield components of
soybean in addition to estimation the residues of these pesticides in the harvested
soybean seeds.
Treatments were as follow:
A. Insecticide treatments:
1.
Treated with Malathion at the rate of 300 cm3/fed.
2.
Untreated with Malathion.
B. Weed control treatments:
1.
Butralin (Amex) 48% EC at 2 L/fed., soil surface application (directly, after
sowing and before irrigation).
2.
Fluazifop-P-butyl (Fusilade super) 12.5% EC at the rate of 1.5 L/fed (applied
at 25 DAS).
3.
Hand hoeing two times (carried out at 25 and 40 DAS).
4.
Control (unweeded).
Soybean hybrid seeds Giza 22 was sown after false irrigation at 17 May in
both seasons. The experimental design was split plot with six replications.
Insecticide treatments were arranged at random in the main plots and weed control
treatments were randomly arranged in the sub plots.
Average number of weed flora in the untreated plots in the first season was
about 350 and 304 weed/m2 while under the second season was about 259 and
257 weed/m2 at 60 and 80 DAS, respectively.
Approximately 81 and 85 % of these weeds were narrow-leaved species,
while only 19 and 15 % were broadleaf species in 2006 season, while under the
second season conditions, narrow-leaved species were about 71 and 62 % while
29 and 38 % were broadleaf species at 60 and 80 DAS, respectively. The most
dominant weeds accompanied with soybean plants in the experimental site were
Echinochloa colonum (35.8 and 41.4 %), Setaria viridis (23.6 and 12.2 %),
Dinebra retroflexa (16.8 and 17%) as grassy weeds and Portulaca oleraceae(16.3
and 11.9 %) as broad-leaved weeds in addition to Cyperus rotundus(6.4 and 2.7
%) as a perennial weed in both 2006 and 2007 seasons, respectively.
During growing season, weeds characters were recorded twice, after 60 and
80 days from sowing. While at harvest, plant characters, yield and yield
components of soybean were recorded and pesticides residues in resulted soybean
seeds were determined.
The most important results could be summarized as follows:
I-
Weed characters
A-
Narrow-leaved weeds
1-
Number of narrow-leaved weeds tended to be lower with spraying malathion,
but the differences in weed density between plots that treated with malathion
and the other one did not reach. Weed control treatments had a significant effect
on dry weight of narrow-leaved at 60 and 80 DAS during both seasons.
All weed control treatments significantly superior over the untreated plots. The
highest reduction in dry weight was obtained from hand hoeing twice (89.6 and 82%)
followed by fluazifop-Pbutyl (86.3 and 80.9 %) and butralin treatments (87.8 and 77.5
%) without significant differences between them in the first season at both 60 and 80
DAS, respectively comparing with the unweeded control. The results of the first
survey in the second season gave the same trend, while there were significant
differences between hoeing, fluazifop-P-butyl, and butralin treatments in reducing the
dry weight of narrow-leaved weeds at 80 DAS.
The interaction between Malathion and weed control treatment was significant
for dry weight of narrow leaved weeds in the two surveys in both seasons. Hand
hoeing twice that treated with Malathion recorded the best reduction in the dry weight
of weeds at the first survey in both seasons, while at the second survey, the
application of fluazifop-P- butyl gave the best results in this respect comparing with
plots of control that treated with Malathion.
B-
Broad-leaved weeds
2-
Number of broad-leaved weeds tended to be lower with spraying malathion, but
the differences in weed density between plots that treated with malathion and
the other one had not reach to the level of significant at the two evaluation
periods (60 and 80 DAS) and this effect was constant from season to another,
except for the results of the first survey (60 DAS) in 2006 season which gave an
opposite trend where weeds weight tended to be higher with spraying
malathion.
Weed control treatments had a significant effect on number of broad–leaved
weeds at the two surveys in both seasons. Hand hoeing twice significantly decreased
the number of broad-leaved weeds by 60.9 and 74.6% at 60 DAS in the first and
second seasons, respectively and recoded 87.7% control percent at 80 DAS in the first
season as compared to the unweeded plots. Butralin treatment gave 66.2% at 80 DAS
in the first season as compared to the untreated plots. While, fluazifop-P-butyl gave
an opposite trend and increased the number of weeds as compared to the untreated
plots at the two surveys in both seasons.
The interaction (M x W) effect was significant in the two surveys in both
seasons. The lowest weed number of broadleaved weeds was obtained by hand hoeing
plots that treated with malathion at the first survey in both seasons, also the second
survey in the first season or butralin with malathion at 80 DAS in 2007 season. The
lowest control percent was obtained by the application of fluazifop-P-butyl which
treated with Malathion in 2006 and 2007 seasons.
1-
Fresh weight of broad-leaved weeds tended to be lower with spraying
malathion, in the first survey (60 DAS) in both season, while the results of the
second survey (80 DAS) gave an opposite trend where weeds weight tended to
be higher with spraying malathion, but the differences in fresh weight between
plots that treated with malathion and the other one did not reach to the level of
significant at the two evaluation periods and this effect was constant from
season to another. Weed control treatments had a significant effect on fresh
weight of broad-leaved weeds at 60 and 80 DAS in 2006 season only. Hand
hoeing twice gave the greatest control percent and significantly reduced the
fresh weight of broad–leaved weeds than the untreated plots by about 83.7 and
87.8% at 60 and 80 DAS, respectively in 2006 season.
The interaction between Malathion and weed control treatments was not
significant for the fresh weight of broadleaved weeds at 60 and 80 DAS in both 2006
and 2007 seasons.
2-
Dry weight of broad-leaved weeds tended to be lower with spraying malathion
except for the results of the second survey (80 DAS) in 2007 season which gave
an opposite trend where weeds weight tended to be higher with spraying
malathion, but the differences in dry weight between plots that treated with
malathion and the other one did not reach to the level of significant at the two
evaluation periods (60 and 80 DAS) and this effect was constant from season to
another.
Weed control treatments had a significant effect on dry weight of broad-leaved
weeds (g/m2) at 60 and 80 DAS in 2006 season only. Hand hoeing twice was the only
treatments which significantly reduced the dry weight of these weeds, where recorded
the highest reduction percentage (81.9 and 84.3%) comparing with unweeded control
at first and second surveys.
The interaction between malathion and weed control treatments was significant
at the second survey of 2006 season and at the two evaluation surveys of 2007 season,
where hand hoeing plots that treated with malathion recorded the most reduction in
the dry weight of broad-leaved weeds, comparing with the untreated control at 60
DAS in 2007 season or fluazifop-P-butyl that treated with malathion at 80 DAS in
both seasons.
C-
Total weeds:
1-
Number of total weeds tended to be lower with spraying malathion, but the
differences in weed density between plots that treated with malathion and the
other one had not reach to the level of significant at the two evaluation periods
(60 and 80 DAS) and this effect was constant from season to another.
All studied weed control treatments had significant effects in controlling weeds
comparing with the unweeded control in both surveys and seasons. Hand hoeing twice
recorded the greatest mortality percentage and significantly superior over fluazifop-Pbutyl in the first season only. Using hand hoeing twice controlled weeds by about 67.7
and 60.7% at 60 DAS, while the reduction in weed density raised to about 82.5 and
63.7% at 80 DAS in 2006 and 2007 seasons, respectively as compared to unweeded
control. While butralin at 2 L/fed controlled weeds by about 63.7 and 50.4% at 60
DAS and raised to about 74.4 and 66.0 % at 80 DAS in 2006 and 2007 seasons,
respectively as compared to untreated control.
While using fluazifop-P-butyl at 1.5 L/fed gave the lowest reduction 50.7 and
38.5% at 60 DAS and raised to about 67.8 and 46.7 % at 80 DAS in 2006 and 2007
seasons, respectively as compared to unweeded control.
The effect of interaction between malathion and weed control treatments was
significant in the two surveys in both seasons. Hand hoeing plots that treated with
malathion gave the best results in the two surveys in both seasons comparing with the
unweeded plots that untreated with malathion.
2-
Fresh weight of total weeds tended to be lower with spraying malathion, in the
first survey (60 DAS) in both season, while the results of the second survey (80
DAS) gave an opposite trend where weeds weight tended to be higher with
spraying malathion, but the differences in fresh weight between plots that
treated with malathion and the other one did not reach to the level of
significance at the two evaluation periods and this effect was constant from
season to another.
Weed control treatments had a significant effect on fresh weight of total weeds,
where all weed control treatments significantly superior over the untreated plots at 60
and 80 DAS in both seasons. The highest reduction in fresh weight of total weeds in
the first season achieved with using hand hoeing (89.8 and 88.9%), butralin (85 and
74.1%) and fluazifop-P-butyl (72.2 and 54.8%) at (60 and 80 DAS), respectively, as
compared to the untreated plots. In this respect, the results of the second season were
about 88.8 and 85.7 % for using hand hoeing twice, about 82 and 63.4 % with
spraying fluazifop-P butyl at the rate of 1.5 L./fed, while butralin gave the lower
control percentage (80.8 and 61.1 %).
The interaction effect was significant for fresh weight of total weeds in the two
evaluation samples of both seasons. Hand hoeing plots that treated with malathion
resulted in the lowest fresh weight at 60 DAS, while the same treatment without
malathion gave the best results at 80 DAS, as compared to the unweeded control
which recorded the highest fresh weigh in both 2006 and 2007 seasons.
3-
Dry weight of total weeds tended to be lower with spraying malathion, but the
differences in dry weight between plots that treated with malathion were
significant in the first survey (60 DAS) in 2007 season only.Weed control
treatments had a significant effect on the dry weight of total weeds in both
seasons. Hand hoeing twice recorded the greatest reduction percentage and
significantly superior over fluazifop-P-butyl at the second survey in 2006 season
and the two surveys in 2007 season.
In 2006 and 2007 seasons, respectively as compared to unweeded control, using
hand hoeing twice controlled weeds by about 88.4 and 79 % at 60 DAS and the
reduction reached to about 82.0 and 81.5 % at 80 DAS, but using butralin at 2 L/fed.
controlled weeds by about 82.1 and 64.2 % at 60 DAS and the reduction decreased to
about 63.1 and 56.1 % at 80 DAS, while using fluazifop-P-butyl at 1.5 L/fed. gave the
lowest reduction 79.7 and 61.5 % at 60 DAS and the reduction in total dry weight
raised to about 38.8 and 60.7 % at 80 DAS.
The effect of interaction was significant at first and second surveys during 2006
and 2007 seasons. The best results in reducing the weight of total weeds was obtained
by hand hoeing treated with malathion at 60 and 80 DAS in both seasons as compared
to the unweeded control which recorded the highest dry weigh in both 2006 and 2007
seasons.
II - Soybean plant characters:
1-
Plant height:
Final plant height of plots that treated with malathion in both seasons tended to
be higher, but the differences between plots that treated with malathion and the other
one were nearly from the level of significant.
Weed control treatments had a significant effect on final plant height in the first
season only. Using hand hoeing twice significantly reduced soybean plant height by
about 10.4 % as compared to unweeded control in 2006 season. Butralin, untreated
control or fluazifop-P- butyl treatments were significantly superior over hand hoeing
in the height of soybean plants and recorded the tallest plants 127.3, 127 and 122.5
cm, respectively as compared to plants of hoed plots (113.8 cm). Using hand hoeing
caused a significant reduction in soybean plant height by about 10.4 and 8.9% as
compared to the unweeded control in 2006 and 2007 seasons, respectively.
Soybean final plant height had significantly affected by the interaction between
malathion and weed control treatments in both seasons. The tallest plants were
obtained from the unweeded control plots that treated with malathion (131.5 and 131
cm), while the shortest plants (104.2 and 101.8 cm) were obtained from hoed plots
without malathion in the first and second season, respectively.
2-
Number of pods/plant:
Number of pods/plant did not affect by malathion treatment in both seasons.
Weed control treatments had a significant effect on the final number of pods/plant at
harvest in 2006 and 2007 seasons. Hand hoeing (twice) gave the highest number of
pods/plant and significantly superior over the unweeded control. Hand hoeing (twice),
Fluazifop-P-butyl (1.5 L/fed) and butralin (2 L/fed) treatments raised the number of
pods/plant by about 45.97,36.95 and 34.77 % in 2006 season and about 46.63, 28.83
and 28.45 % in 2007 season, as compared to the untreated check.
Number of pods per plant was significantly affected by the interaction between
malathion and weed control treatments in both seasons. The plots that hoed two times
without malathion recorded the highest number of pods per plant (46.63 and 56.1),
while the lowest number (29.5 and 35.3) was obtained from the unweeded control that
treated with malathion in 2006 and 2007 seasons, respectively.
3-
Biological yield in grams/plant:
There were no significant effects for using malathion on biological yield in
grams/plant in both 2006 and 2007 seasons.
All weed control treatments recorded a significant increase in biological yield in
grams/plant as compared to weedy check without significant differences between
them.
Hand hoeing (twice), butralin (2 L/fed) and Fluazifop-P-butyl (1.5 L/fed)
treatments increased the biological yield/plant in 2006 season by about 35, 20 and 14
% and these increases in 2007 season raised to be about 44, 32.8 and 33.5 %,
respectively as compared to the untreated check.
Biological yield in grams/plant was significantly affected by the interaction
between malathion and weed control treatments in 2007 season only. Hand hoeing
twice with or without malathion recorded the highest biological yield (49.6 or 50.2
g/plant) and were the only treatments that gave a significant increase in the biological
yield in 2007 season as compared to the unweeded control that treated with malathion.
4-
Pods weight/plant:
Malathion treatment had not cause any significant effect on pods weight/plant in
both 2006 and 2007 seasons.
All weed control treatments recorded a significant increase in pods weight/plant
as compared to weedy check without significant differences between them.
The highest pods weight/plant were recorded by using hand hoeing twice (26.1
and 32.4 g/plant), while the lowest weight were obtained from the unweeded control
(15.68 and 15.9 g/plant) in 2006 and 2007 seasons, respectively.
The most effective treatments were hand hoeing (twice), butralin (2 L/fed) and
fluazifop-P-butyl (1.5 L/fed), respectively.
These treatments increased pods weight/plant by 66, 58 and 55 % 2006 season
and these increases raised to be about 103, 88 and 70 %, respectively in 2007 season
as compared to the untreated check.
Pods weight/plant was significantly affected by the interaction between
malathion and weed control treatments in both seasons. Hand hoeing twice without
malathion recorded the highest pods weight/plant (26.75 and 34.2) in 2006 and 2007
seasons, respectively as compared to the unweeded control that treated with
malathion.
5-
Seed number /pod:
Malathion had no significant effect on seed number per pod in both seasons.
Seed number per pod had significantly affected by weed control treatments in 2007
season. The application of butralin at 2 L/fed produced the maximum seed number per
pod (2.47 seeds/pods), and were the only treatments which significantly superior over
the unweeded control which recorded the lowest number (1.93 seeds/pods). The
interaction between malathion and weed control treatments had no significant effect
on seed number per pod in both 2006 and 2007 seasons.
6-
Hundred seed weight:
There was no significant effect for using malathion or not on 100 seed weight in
both seasons. The differences in 100 seed weight as affected by weed control
treatments did not reach to the level of significant in both seasons. The interaction
between malathion and weed control treatments had no significant effect on this
character in both seasons.
7-
Seed yield/plant (gm):
Data showed that there were no significant differences in seed yield resulted
from treated or untreated plots with malathion in both seasons.
All weed control treatments recorded a significant increase in seed yield/plant as
compared to weedy check without significant differences between them. Hand hoeing
(twice), butralin (2 L/fed) and Fluazifop-P-butyl (1.5 L/fed) treatments increased the
seed yield/plant by about 14. 20, 13.9 and 13.6 %, respectively in 2006 season and
these increases raised to be about 48.9, 50.5 and 49.5 %, respectively in 2007 season
as compared to the untreated check.
Seed yield/plant was significantly affected by the interaction between malathion
and weed control treatments in 2006 season only.
Hand hoeing treatment without malathion recorded the highest seed yield/plant
(14.3 g/plant) and was the only treatments that gave a significant increase in this
character as compared to the unweeded control that treated with malathion (8.4
g/plant).
III – Soybean yield characters:
1.
Number of harvested plant (1000/fed):
There was no significant effect for using malathion or not on finial soybean
population in both seasons. It could be noticed that average finial soybean population
tended to be higher with spraying malathion, but the differences in soybean
population between plots that treated with malathion and the other one had not reach
to the level of significant and this effect was constant from season to another.
Data also revealed that the differences in finial soybean population as affected
by weed control treatments did not reach to the level of significant in both seasons.
The interaction between malathion and weed control treatments had no
significant effect on this character in both seasons.
2-
Biological yield (ton/fed)
There was no significant effect for using malathion or not on biological yield in
both season.
The differences in biological yield as affected by the studied weed control
treatments were significant in both seasons. Both hand hoeing and butralin treatments
had a significant effect on the biological yield as compared to the untreated control in
2006 and 2007seasons. The highest biological yield was achieved by applying hoeing
twice (4.261 and 4.725 ton/fed) or butralin (3.395 and 4.6 ton/fed) in 2006 and 2007
seasons, respectively. both treatments improved yield by about (56 and 38 %) for
hoeing and (30.395 and 34.7 %) for butralin in 2006 and 2007 seasons, respectively as
compared to yield harvested from the unweeded plots which resulted in the lowest
yield (2.73 and 3.41 ton/fed). Fluazifop-P-butyl failed to provide the desired
biological yield in both growing seasons.
Biological yield significantly affected by the interaction between malathion and
weed control treatments in both seasons.
Hoeing twice in combination with malathion recorded the highest values for
biological yield (4.678 and 4.800 ton/fed), while the lowest biological yield (2.431
and 3.2 ton/fed) had achieved from the untreated plots without malathion in 2006
season and with malathion in 2007 season.
3-
Seed yield (ton / fed) :
Soybean seed yield (ton/fed) tended to be higher with spraying malathion, but
the differences in seed yield between plots that treated with malathion and the other
one did not reach to the level of ignificant in both seasons.
Weed control treatments had a significant effect on the final oybean seed yield
in both seasons. Hand hoeing and butralin reatments recorded the highest significant
improvement in seed yield 59.8 and 45.4 %) in 2006 season and this improvement
reached to 62.7 and 50.0 %), respectively in 2007 as compared to the yield esulted
from the unweeded plots (0.756 and 0.704 ton/fed).
Fluazifop-P- butyl caused a significant increase in seed yield in the irst season
only without significant differences between it and the ield resulted from hand hoeing
or butralin treatments.
Seed yield was significantly affected by the interaction between alathion and
weed control treatments in both seasons, where the highest significant values were
found with the application of hand oeing twice with malathion in both 2006 and 2007
seasons. While he lowest yield (0.728 and 0.671 ton/fed) had resulted from the ontrol
plots without and with Malathion in the first and the second season, respectively.
IV- Pesticide residues in soybean seeds:
The findings for final part of study demonstrated that Malathion nd fluazifop-Pbutyl pesticide residues are rarely detected on soybean eeds and when detected, the
levels are generally well below the esticide codex of U.K but the residue levels of
butralin were over RL of U.K. The results obtained can provide some information for
onsumers who are concerned about the presence of pesticide residues and provide a
reasonably, safe measure and assurance for the public that soybean seeds is safe and
wholesome.