Control of cabbage insect pests, Plutella xylostella, Pieris rapae, and Spodoptera litura, using biological control agents and chemical insecticides Q.J. Li1, X.H. Qiu1, R-U. Ehlers2, A.M. Burnell1, D. Sulistyanto4 and R. Han 1 1. Guangdong - PowerPoint PPT Presentation

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Control of cabbage insect pests, Plutella xylostella, Pieris rapae, and Spodoptera litura, using biological control agents and chemical insecticides Q.J. Li1, X.H. Qiu1, R-U. Ehlers2, A.M. Burnell1, D. Sulistyanto4 and R. Han 1 1. Guangdong

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Title: Control of cabbage insect pests, Plutella xylostella, Pieris rapae, and Spodoptera litura, using biological control agents and chemical insecticides Q.J. Li1, X.H. Qiu1, R-U. Ehlers2, A.M. Burnell1, D. Sulistyanto4 and R. Han 1 1. Guangdong


1
Control of cabbage insect pests,
Plutella xylostella, Pieris rapae, and Spodoptera
litura, using biological control agents and
chemical insecticides Q.J. Li1, X.H. Qiu1, R-U.
Ehlers2, A.M. Burnell1, D. Sulistyanto4 and R.
Han 1 1. Guangdong Entomological Institute,
Guangzhou 510260, China.2. Department of
Biotechnology and Biological Control,
Christian-Albrechts-University Kiel,
Germany.3. Department of Biology, National
University of Ireland Maynooth.4. Plant
Protection Department, The University of Jember,
Indonesia.
2
Objective
  • To substitute chemical insecticides by
    introducing integrated biological control agents
    (EPN, Bt, and insect viruses)
  • To obtain sustainable control of cabbage pests
    during the growth of the cabbages in the field
  • To increase yields, cabbage quality and economic
    output.

3
Materials and methods
  • Test 1
  • The tests were conducted from September to
    November in 2003 in Guangzhou.
  • Introduced Bt, Bta, Bt/PxGV, Bt/PrGV, SpltMNPV,
    and Steinernema carpocapsae All to control
    Plutella xylostella, Pieris rapae, and Spodoptera
    litura (Table 1).
  • Area per treatment was 30 m2.
  • Usually the cabbage plants were harvested before
    47 days, depending on the weather conditions.

4
Table 1 The time of application, kind and
concentration of biological insecticides used in
test 1
 
5
Results
  • Test 1
  • (For the control of P. xylostella Fig. 1)
  • The density of P. xylostella with biological
    insecticides was controlled at a low level (lt0.9
    larvae/plant) and was significantly lower
    compared with the untreated controls after
    treatment (2.13.3 larvae/plant).
  • Seven days after the second spray, Bt/PxGV
    produced the best control among biological
    insecticides.

6
Fig. 1 Plutella xylostella density after
treatment with several biological
insecticides.Note Bio-insecticides were
applied on day 37 (without SpltMNPV) and day 40
(with SpltMNPV . Arrows indicate date of
spraying.
With SpltMNPV
Without SpltMNPV
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  • Results
  • Test 1
  • (For the control of P. rapae Fig. 2)
  • Four days after the first spray, the Bta, Bt,
    Bt/PrGV, Bt/PxGV, and nematodes produced 0, 62.5,
    100, 100, and 30 P. rapae reduction,
    respectively.
  • Three days after the second spray, all treatments
    with biological insecticides produced 87.6100
    P. rapae reduction.

13
Fig. 2. Pieris rapae density after treatment
with several biological insecticides.Note
Bio-insecticides were applied on day 37 (without
SpltMNPV) and day 40 (with SpltMNPV . Arrows
indicate date of spraying.
Without SpltMNPV
With SpltMNPV
14
  • Results
  • Test 1
  • (For the control of S. litura Fig. 3)
  • At 4 days after the first application, all
    treatments failed.
  • At 3 days after the second application, S. litura
    population density in the treatments with all
    biological insecticides (lt0.2 larvae/plant) was
    significantly lower compared with the untreated
    controls (0.7 larvae/plant).
  • In general, treatments with Bta SpltMNPV and
    nematodes SpltMNPV produced the best control
    among treatments.

15
Fig. 3. Spodoptera litura density after
treatment with several biological
insecticides.Note Bio-insecticides were
applied on day 37 (without SpltMNPV) and day 40
(with SpltMNPV . Arrows indicate date of spraying.
With SpltMNPV
Without SpltMNPV
16
  • Materials and methods
  • Test 2
  • The tests were conducted from October to November
    in 2003 in Guangzhou.
  • The efficacy of biological insecticides ( Bt/PxGV
    and Steinernema carpocapsae All) and chemical
    insecticides (chlorpyrifos/cypermethrin and
    avermectin/phoxim ) to control Plutella
    xylostella, Pieris rapae, and Spodoptera litura
    was compared (Table 2).
  • Damage levels of cabbage by pests were evaluated
    after the treatment.
  • Area per treatment was 150 m2.

17
Table 2 The time of application, kind and
concentration of chemical and biological
insecticides used in test 2
18
  • Results Test 2
  • (For the control of P. xylostella Fig. 4)
  • At 4 days after the first application, the
    population density of P. xylostella among all
    treatments was not significantly different.
  • After the first application, the population
    density of P. xylostella with biological
    insecticide was kept at a low level (lt0.5
    larvae/plant), but the population density of P.
    xylostella with chemical insecticide increased
    significantly (1.4 larvae/plant).
  • The population density of P. xylostella with two
    sprays of biological insecticide was controlled
    at a low level (lt0.5 larvae/plant). The
    population density of P. xylostella with three
    sprays of chemical insecticide was controlled at
    a low level (lt0.5 larvae/plant).

19
Fig. 4 Plutella xylostella density after
treatment with chemical and bio-insecticides.Not
e Chemical insecticides chlorpyrifos/cypermethri
n (sprayed on day 22), chlorfenapyr (day 34), and
avermectin/phoxim (day 37) Bio-insecticides
Bt/PxGV (sprayed on day 22) and S. carpocapsae
All (on day 34) . Arrows indicate date of spray.
20
  • Results
  • Test 2
  • (For the control of P. rapae Fig. 5)
  • At 4 days after the first application, both
    treatments of chemical and biological insecticide
    produced 100 P. rapae reduction.
  • The population density of P. rapae treated with
    chemical and biological insecticides was always
    controlled at very low level (lt0.04 larvae/plant)
    and was always significantly lower compared with
    the untreated control(0.140.49 larvae/plant).

21
Fig. 5 Pieris rapae density after treated with
chemical and bio-insecticides.Note Chemical
insecticides chlorpyrifos/cypermethrin (sprayed
on day 22), chlorfenapyr (day 34), and
avermectin/phoxim (day 37) Bio-insecticides
Bt/PxGV (sprayed on day 22) and S. carpocapsae
All (on day 34) . Arrows indicate date of spray.
22
  • Results
  • Test 2
  • (For the control of S. litura Fig. 5)
  • Before the second application, there were not
    significant differences among population density
    of S. litura of all treatments.
  • At 3 days after the second application, the
    population density of S. litura treated with
    chemical and biological insecticide (lt0.03
    larvae/plant) was significantly lower compared
    with the untreated control (0.17 larvae/plant).

23

Fig. 6. Spodoptera litura density after
treatment with chemical and bio-insecticides. Not
e Chemical insecticides chlorpyrifos/cypermethri
n (sprayed on day 22), chlorfenapyr (day 34), and
avermectin/phoxim (day 37) Bio-insecticides
Bt/PxGV (sprayed on day 22) and S. carpocapsae
All (on day 34) . Arrows indicate date of
spraying.
24
  • Results
  • Test 2
  • The foliar damage levels of cabbages increased
    with time .
  • Both treatments of chemical and bio-insecticides
    significantly reduced plant damage, and
    biological insecticides significantly reduced
    plant damage compared to chemical insecticides.

Table 11. Mean number of feeding hole damage by
insect pests per cabbage plant (n25) recorded
from the treatments with chemical insecticides,
biological insecticides, and an untreated control
(water only)
25
  • Materials and methods
  • Test 3
  • The tests were conducted from October to
    November in 2003 in Guangzhou.
  • The efficacy of the biological insecticides (Bta
    and Bt/PxGV ) and the chemical insecticides
    (chlorpyrifos/cypermethrin and avermectin/phoxim
    ) to control Plutella xylostella, Pieris rapae,
    and Spodoptera litura was compared (Table 3).
  • Damage levels of cabbage by pests were evaluated
    after treatment.
  • Area per treatment was 60 m2.

26
Table3 The time of application, kind and
concentration of chemical and biological
insecticides used in test 3
27
  • Results
  • Test 3
  • (For the control of P. xylostella Fig. 7)
  • At 4 days after the first application, the
    population density of P. xylostella among all
    treatments was not significantly different.
  • At 11 days after the first application, the
    population density of P. xylostella with chemical
    insecticide (1.2 larvae/plant) increased rapidly
    and was significantly higher compared with the
    untreated control and the biological insecticide
    (lt0.4 larvae/plant).
  • After the second application, the population
    density of P. xylostella with chemical and
    biological insecticide was controlled at a low
    level (lt0.6 larvae/plant) and was significantly
    lower than that with the untreated control (1.0
    larvae/plant).

28
Fig. 7 Plutella xylostella density after treated
with chemical and bio-insecticides.Note
Chemical insecticides chlorpyrifos/cypermethrin
(sprayed on day 23) and avermectin/phoxim (day
34) Bio-insecticides Bta (sprayed on day 23)
and Bt/PxGV (on day 34) . Arrows indicate date of
spraying.
29
  • Results
  • Test 3
  • (For the control of P. rapae Fig. 8)
  • At 4 days after the first application, both
    treatments of chemical and biological
    insecticides produced 100 P. rapae reduction.
  • After treatment, the population density of P.
    rapae treated with chemical and biological
    insecticides was always controlled at very low
    level (lt0.03 larvae/plant) and was always
    significantly lower compared with the untreated
    control (0.180.5 larvae/plant).

30
Fig. 8 Pieris rapae density after treatment with
chemical and bio-insecticides.Note Chemical
insecticides chlorpyrifos/cypermethrin (sprayed
on day 23) and avermectin/phoxim (day 34)
Bio-insecticides Bta (sprayed on day 23) and
Bt/PxGV (on day 34) . Arrows indicate date of
spraying.
31
  • Results
  • Test 3
  • (For the control of S. litura Fig. 9)
  • At three days after the second application, the
    population density of S. litura with all
    treatments was very low (lt0.08 larvae/plant) and
    was not significantly different among treatments.
  • At 7 days after the second application, the
    population density of S. litura treated with
    chemical (0 larvae/plant) and biological
    insecticides (0.12 larvae/plant) was
    significantly lower compared with the untreated
    control(0.22 larvae/plant).

32

Fig. 9 Spodoptera litura density after treated
with chemical and bio-insecticides. Note
Chemical insecticides chlorpyrifos/cypermethrin
(sprayed on day 23) and avermectin/phoxim (day
34) Bio-insecticides Bta (sprayed on day 23)
and Bt/PxGV (on day 34) . Arrows indicate date of
spraying.
33
  • Results
  • Test 3
  • The foliar damage levels of cabbages increased
    with time (Table 15).
  • Both treatments of chemical and biological
    insecticides significantly reduced plant damage,
    but the biological insecticide treatment
    significantly reduced plant damage compared to
    chemical insecticides.

Table 15 Mean number of damage holes by insect
pests per cabbage plant (n10) recorded from the
treatments with chemical insecticides, biological
insecticides, and an untreated control (water
only )
34
  • Materials and methods
  • Test 4
  • The tests were conducted from October to December
    in 2003 in Guangzhou.
  • The efficacy of the biological insecticides
    (AcMNPV, PXGV, Bta, Steinernema carpocapsae All
    and Bt/PxGV ) and the chemical insecticides
    (avermectin/phoxim and fipronil) to control
    Plutella xylostella, Pieris rapae, and Spodoptera
    litura was compared (Table 4).
  • Damage levels of cabbage by pests were evaluated
    after treatment.
  • Area per treatment was 60 m2.

35
Table 4 The time of application, kind and
concentration of chemical and biological
insecticides used in test 4
36
  • Results
  • Test 4
  • (For the control of P. xylostella Fig. 10)
  • During the tests, P. rapae and S. litura larvae
    and pupae were not detected.
  • From 7 days after the first application until the
    end of the study, the population density of P.
    xylostella with all treatments of chemical and
    biological insecticides (0.180.60 larvae/plant)
    was controlled at a low level and was
    significantly lower compared with the untreated
    control (0.931.98 larvae/plant).

37
T1 Avermetin/phoxim (day 19, 26), fipronil (day
33, 46)T2 AcMNPV with 0.03 adjuvant (day 19,
26), Bta (day 33), Bt/PxGV(day 46)T3 PxGV with
0.03 adjuvant (day 19, 26), S.c. All (day 33),
Bt/PxGV (day 46)T4 Bta (day 19, 26), PxGV with
0.03 adjuvant (day 33), Bt/PxGV (day 46) T5
Control (with water)Fig. 10 Plutella xylostella
density after treatment with chemicals and
bio-insecticides. Note Arrows indicate date of
spraying.
38
  • Results
  • Test 4
  • There were no differences in the foliar damage
    levels of cabbages with chemical and
    bio-insecticides at any time.
  • All treatments of chemical and biological
    insecticide significantly reduced plant damage.

Table 17 Mean number of damage holes by insect
pests per cabbage plant (n5) recorded from the
treatments with chemical insecticides, biological
insecticides, and an untreated control (water
only)
39
  • Results
  • Test 4
  • There were no significant differences among mean
    weights of cabbage plants treated with chemical,
    biological insecticides and water only (Table
    18).

Table 18 Mean weight per cabbage plant (n30)
recorded from the treatments with chemical
insecticides, biological insecticides, and an
untreated controls (water only)
40
Conclusions
  • The results show that the bio-insecticides used
    in these tests can control P. xylostella and P.
    rapae effectively.
  • The population densities of P. xylostella and P.
    rapae were kept at low levels (P. xylostella lt 1
    larva or pupa per plant, P. rapae lt 0.1 larva or
    pupa per plant) at least for one week after
    application of the bio-insecticides with proper
    timing.
  • Bio-insecticides were equal or superior to
    chemicals for controlling P. xylostella and P.
    rapae.

41
AcknowledgmentsWe acknowledge the financial
support of the EU INCO programme
(ICA4-2001-10003).
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