Effect of IPM modules on the reduction (%) of infested twig over control

Development of IPM modules using microbials and their derivatives for managing bean aphid, Aphis craccivora Koch

Volume- I | Issue – I

Authors

Abstract

Bean aphid is a serious pest which causes enormous loss of yield of country bean. An experiment was conducted at the Entomology Field Laboratory of Bangladesh Agricultural University, Mymensingh, Bangladesh during October 2018 to March 2019 to develop IPM modules using microbials and their derivatives and a botanical for managing bean aphid on IPSA Seem-2. IPM modules were evaluated based on different parameters viz. percentage of twig, flower and pod infestation at different time intervals and yield of marketable pod (ton ha-1). Eight treatments (seven IPM modules) viz. T1: Bt + Spinosad, T2: B. bassiana + Lufenuron, T3: Bt Abamectin, T4: Bt + Neem oil, T5: Bt + Lufenuron, T6: B. bassiana + Abamectin, T7: Bt + Buprofezin, T8: Control was included in the experiment. The experiment was laid out in RCB design with 3 replications of each treatment. The lowest infested twig, flower and pod were found 8.12, 4.55 and 5.13%, respectively at Beauveria bassiana + Abamectin sprayed plot after 1st spray. The efficacy of other IPM packages was more or less similar. After 2nd spray the lowest infested twig, flower and pod was observed 2.56, 1.73 and 2.16%, respectively at Beauveria bassiana + Abamectin sprayed plot. Similarly, after 3rd spray the lowest infested twig, flower and pod were 1.08, 0.47, and 0.78%, respectively at Beauveria bassiana + Abamectin sprayed plot. The highest twig, flower and pod infestation was always recorded from control treatment in all three sprays. The highest reduction of infested twig, flower, and pod over control was observed 98.33, 98.9 and 98.99%, respectively from the plots treated with Beauveria bassiana + Abamectin. The highest yield (12.46 ton ha-1) was also found from B. bassiana + Abamectin sprayed plot but the lowest yield was in control plots. From the present findings it can be concluded that B. bassiana + Abamectin might be applied successfully for the management of country bean aphid as it provided significant protection of twig, flower and pod and subsequently produced the highest pod yield.

Introduction

Country bean, Lablab purpureus (L) is an internal vegetable of Indo-Bangladesh region. The plant is long trailing and branched. It is a very important leguminous vegetable of Bangladesh. In the perspective of dry matter, calorie, protein, fat, vitamin A and B the pods are the superior most in spreading nature. Nutritionally, the seed is top in the list of pulse crop. It is rich in carbohydrate, protein, fat, minerals. The leaves and seeds contain 20–28% protein, with a well-balanced amino acid composition1. Bean contains several vital nutrients, including folate which can help to prevent neural tube defects in a fetus during pregnancy. It also contains antioxidant called polyphenols which reduces risk of cancer. Bean is normally grown during the rabi or winter season. In Bangladesh total land area under bean cultivation 51595 acres and the production is about 137495 ton 2016-17 years2. But the production is low according to the demand.

Bean aphid, Aphis craccivora Koch is a destructive pest of country bean. The young plants suffer heavily from the attack of bean aphid and may die3. All growth stages of bean crop are very susceptible to bean aphid infestation and may result in high yield loss if not controlled. Bean aphid causes both the direct and indirect damage. By sucking cell sap they cause direct damage to the host and also they transmit common mosaic viruses during the sucking activity which is the indirect damage.  Aphids secret honey dew which attracts sooty mould fungus on leaf surfaces and reduces photosynthetic area depriving the growing plant and the developing grains in the pods of nutrients thus causing low yields4. Aphis craccivora Koch is the most serious pest of bean plants from seedling to pod bearing stage, causing considerable yield loss5. The pest causes up to 40% reduction of crop yields in Asia6. It has been reported as high as 100% yield reduction of different bean crops due to aphid infestation7. Due to severity of infestation plants fail to give flowering and pods setting resulting in 20-40% yield loss8.

To protect the crops from aphids, insecticides are considered essential for their management. A large number of insecticides have been evaluated and recommended from time to time for their control9. Some pesticides have shown efficacy in controlling bean insect infestation but not eco-friendly to natural enemies, to humans, to wildlife safety. So, there is a need for adopting other new alternative in controlling bean aphid. Controlling aphid using non chemical insecticides microbials and their derivatives are most promising and it is eco-friendly and hazardous residual effect free. But in our country the popularity of using microbials and their derivatives is so much negligible. Beauveria bassiana (soil borne fungus), Bacillus thuringiensis (soil dwelling bacteria), Spinosad derived from a soil born bacterium- Saccharopolyspora spinosa, Lufenuron (growth regulator), Neem oil (botanical), Abamectin, Buprofezin are also being used as environmentally safe product. So, the present study has been done giving emphasis on the development of some IPM modules using different microbials and their derivatives and a botanical for managing bean aphid.

Materials and Methods  

Location and soil of the experiment

The experiment was conducted at the Entomology Field Laboratory of Bangladesh Agricultural University, Mymensingh-2202 during the period from October 2018 to March 2019 to develop IPM module using microbials and their derivatives for managing bean aphid in rabi season. The experimental site is located at 24.750 N latitude 90.50 E longitude with an elevation of about 9.2 m above from the sea. The field experiments were conducted under sub-tropical climate, which is characterized by moderately low temperature, scanty rainfall during October- March. The soil of the field experiment area was under Old Brahmaputra Alluvial Tract under the Agro Ecological Zone 9 with sandy loam soil and texture having good irrigation and drainage facilities. The soil was silty loam in texture having pH 6.94, organic matter 1.62% and cation exchange capacity 15.00 m.eq 100-1 g soil10.

Development of plants

The land was ploughed and cross-ploughed several times with a power tiller to obtain final tilth that was followed by laddering and spading. The stubbles of the crops and uprooted weeds were removed from the field and the land was then leveled prior to transplanting. The entire experimental field was divided into three blocks and then into 24 plots. Each plot size was 2 ft X 2 ft. Two adjacent unit plots and blocks both were separated by 1 foot apart. The plots were raised by 10 cm from the soil surface keeping the drain around the plots. Seem seeds (variety: IPSA-2 seem) were collected from Balughat bazar, Dhaka cantonment, Dhaka-1206. Seeds were sown in pits (five seeds/pit) followed by a light irrigation to ensure soil moisture for germination. Recommended fertilizer doses of 10 ton cowdung, 25 kg urea, 90 kg TSP, 60 kg MoP, Gypsum 5 kg and 5 kg Boric acid were adopted for one ha land. Half of the dose of urea and the total phosphorus, cowdung, gypsum, boric acid were applied as basal dose and the rest of the urea was applied at 30 days after sowing. Mustard oil cake was also applied at the vegetative stage. Weeding and all suitable agronomic practices were done for proper growth and development of plants. Bamboo stalking was made for propping, allowing easy standing and preventing the plant from lodging. Each experimental plot was tagged properly considering the treatments and replications.

Design of experiment

The experiment was laid out in a Randomized Complete Block Design (RCBD). Each of the treatments was replicated for three times.

Specification of treatments

Treatments IPM modules Dose/L of water
T1 Bacillus thuringiensis  (Bt)+ Spinosad (Tracer 45 SP) 5g + 0.5 ml
T2 Beauvaria bassiana  (Bb)+ Lufenuron (Heron 5 EC) 5g + 0.5 ml
T3 Bacillus thuringiensis (Bt) + Abamectin (Ambush 1.8 EC) 5g + 2.5ml
T4 Bacillus thuringiensis (Bt)+ Neem oil 5g + 1.5 ml
T5 Bacillus thuringiensis (Bt)+ Lufenuron (Heron 5 EC) 5g + 0.5 ml
T6 Beauveria bassiana (Bb)+ Abamectin (Ambush 1.8 EC) 5g + 2.5 ml
T7 Bacillus thuringiensis (Bt)+ Buprofezin (Award 40 SC) 5g + 0.5ml
T8 Control

Data Collection

All the treatments were applied maintaining 15 days intervals and data were collected at 5, 10 and 15 days after spraying. Number of healthy and infested twig, flower and pods and weight of healthy pods for each plot were recorded. Then percentage of infested twig, flower or pod was calculated. The weight of healthy pods plot-1 was measured by an electrical balance. Finally, yield (ton ha-1) was calculated from data found from the plots. Percentage reduction of twig, flower or pod infestation over control and percentage increase of yield over control was calculated using the following formulae.

Data analysis

All the data collected on different parameters were compiled and arranged for statistical analysis. Then the data were analyzed statistically using MSTAT-C package programme. The means were separated using DMRT test.

Results

Effect of IPM modules on the infestation of twig caused by A. craccivora

The effect of IPM modules on the percentage of twig infestation was significant at different time intervals (Table 1).  At 5 DAS, the lowest twig infestation was found at Bb + Abamectin sprayed plot (11.76%) followed by Bt + Spinosad (16.66%). The highest infested twig was observed from control (43.47%) plot.  At 10 DAS, the lowest infested twig was recorded at Bb + Abamectin sprayed plot (11.11%) followed by Bt + Abamectin (17.64%). The highest infested twig was observed from control (44.44%). Similarly, at 15 DAS, the lowest infested twig was found at Bb + Abamectin sprayed plot (8.12%) followed by Bt + Abamectin (14.29%). The highest infested twig was observed from control (50%) plots.

Treatments

5 DAS

10 DAS

15 DAS

No. of healthy twig plot-1

No. of infested twig plot-1

%infestation

No. of healthy twig plot-1

No. of infested  twig plot-1

%infestation

No. of healthy twig plot-1

No. of  infested twig plot-1

%infestation

T1

25.0c

5c

16.66

25c

7cd

21.87

26c

5d

16.13

T2

20.0d

9a

31.03

20d

9bc

31.03

21d

7c

25.00

T3

27.5b

6bc

17.91

28b

6de

17.64

30b

5d

14.29

T4

23.0c

8ab

25.80

23c

8bcd

25.81

26c

6cd

18.75

T5

18.0d

9a

33.33

18de

9bc

33.33

20d

7c

25.93

T6

30.0a

4c

11.76

32a

4e

11.11

34a

3e

8.12

T7

15.5e

9a

36.73

16ef

10ab

38.46

18e

12b

40.00

T8

13.0f

10a

43.47

15f

12a

44.44

16f

16a

50

Level of significance

**

*

*

**

*

*

CV%

6.12

10.83

5.36

10.61

7.82

10.91

Table 1 – Effect of IPM modules on the twig infestation at different days after 1st spray

T1 = Bt + Spinosad, T2= Bb + Lufenuron, T3 = Bt + Abamectin, T4 = Bt + Neem oil, T5 = Bt + Lufenuron, T6 = Bb+ Abamectin, T7= Bt + Buprofezin and T8= untreated control; In column, means followed by different letters are significantly different; * & ** Mean significant at 5% & 1% level of probability, respectively

Treatments

5 DAS

10 DAS

15 DAS

No. of healthy twig plot-1

No. of infested twig plot-1

% infestation

No. of healthy twig plot-1

No. of infested  twig plot-1

% infestation

No. of healthy twig plot-1

No. of  infested twig plot-1

% infestation

T1

27.0 c

12.00b

20.34

27.00c

1.67ef

5.82

30.00c

2.00ef

6.25

T2

23.00d

5.66d

10.47

24.00e

5.00c

17.24

26.00e

3.67cd

12.37

T3

30.33b

4.00ef

11.65

31.00b

3.00de

8.82

32.00b

2.67de

7.70

T4

26.0c

4.66de

13.04

25.67d

4.00cd

13.48

27.67d

3.33de

10.74

T5

21.0d

5.66d

21.23

21f

4.67c

18.19

23.00f

5.00c

17.86

T6

35.0a

3.00f

7.89

35.67a

1.00f

2.73

38.00a

1.00f

2.56

T7

18.0e

10.00c

35.71

17g

8.00b

32.00

20.67g

7.67b

27.72

T8

14.0f

17.00a

54.84

13.33h

17.67a

57.00

13.00h

18.00a

58.06

Level of significance

**

*

**

**

**

**

CV%

4.71

10.03

5.02

5.76

5.68

10.27

Table 2 – Effect of IPM modules on the twig infestation at different days after 2nd spray

After 2nd spray, at 5 DAS, the lowest infested twig was found from Bb +Abamectin sprayed plot (7.89%) followed by Bb + Lufenuron (10.47%) but the highest infested twig was in control (54.84%) (Table2). AT 10 DAS, the lowest infested twig was recorded at Bb + Abamectin sprayed plot (2.73%) followed by Bt + Abamectin (8.82%).The highest infested twig was observed from control (57.00%) (Table 2). Similarly, at 15 DAS, the lowest infested twig was observed in Bb + Abamectin sprayed plot (2.56%) followed by, Bt + Spinosad (6.25%). The highest infested twig was found from control (58.06%).

T1 = Bt + Spinosad, T2= Bb + Lufenuron, T3 = Bt + Abamectin, T4 = Bt + Neem oil, T5 = Bt + Lufenuron, T6 = Bb+ Abamectin, T7= Bt + Buprofezin and T8= untreated control; In column, means followed by different letters are significantly different; * & ** Mean significant at 5% & 1% level of probability, respectively

In case of 3rd spray, at 5 DAS the lowest infested twig was seen at Bb + Abamectin sprayed plot (2.78%) followed by Bt + Spinosad (5.27%). The highest infested twig was observed from control (62.96%) (Table 3).  AT 10 DAS, the lowest infested twig was seen at Bb + Abamectin sprayed plot (1.99%) followed by Bt + Abamectin (4.69%). The highest infested twig was observed from control (68.97%) (Table3). AT 15 DAS, the lowest infested twig was seen at Bb + Abamectin sprayed plot (1.08%) followed by Bt + Abamectin (5.05%). The highest infested twig was observed from control (65.38%).

Treatments

5 DAS

10 DAS

15 DAS

No. of healthy twig plot-1

No. of infested twig plot-1

%infestation

No. of healthy twig plot-1

No. of infested  twig plot-1

%infestation

No. of healthy twig plot-1

No. of  infested twig plot-1

%infestation

T1

30.00c

1.67ef

5.27

29.00b

1.67e

5.45

27.00b

2.33de

7.94

T2

25.00e

3.33cd

11.75

23.00e

3.33cd

12.65

20.00e

2.67cd

11.78

T3

31.00b

2.33def

6.99

27.00c

1.33e

4.69

25.00c

1.33f

5.05

T4

27.00d

3.00cde

10.00

25.00d

3.00d

10.71

22.67d

1.67ef

7.05

T5

20.00f

4.00c

16.67

17.67f

4.33c

20.3

16.00f

3.33c

17.23

T6

35.00a

1.00f

2.78

33.00a

0.67e

1.99

30.00a

0.33g

1.09

T7

18.00g

6.67b

27.04

17.00f

8.00b

32

15.00f

5.00b

25.00

T8

10.00h

17.00a

62.96

9.00g

20.00a

68.97

9.00g

17.67a

65.38

Level of significance

*

**

**

*

**

*

CV%

6.95

7.26

 

8.14

10.06

 

8.45

12.59

Table 3 –  Effect of IPM modules on the twig infestation at different days after 3rd spray

T1 = Bt + Spinosad, T2= Bb + Lufenuron, T3 = Bt + Abamectin, T4 = Bt + Neem oil, T5 = Bt + Lufenuron, T6 = Bb+ Abamectin, T7= Bt + Buprofezin and T8= untreated control; In column, means followed by different letters are significantly different; * & ** Mean significant at 5% & 1% level of probability, respectively.

Figure 1 – Effect of IPM modules on the reduction (%) of infested twig over control at 1st, 2nd, and 3rd sprays

The highest percentage reduction of infested twig over control was observed from the plots treated with Bb + Abamectin (83.8%) in the first spray. However, Bt + Buprofezin (20%) provided the least percentage reduction of infested twig infested by bean aphid (Fig. 1). The efficacy rank of the IPM modules on (%) reduction of infested twig over control was as follows-Bb + Abamectin > Bt + Abamectin > Bt + Spinosad > Bb + Neem oil > Bb + Lufenuron > Bt + Lufenuron > Bt + Buprofezin in first spray. In case of second spray the highest percentage reduction of infested twig over control was observed from the plots treated with Bb + Abamectin (95.5%). However Bt + Buprofezin (52.27%) provided the least percentage reduction of infested twig affected by bean aphid (Fig.1). The efficacy rank of the IPM modules on (%) reduction of infested twig over control was as follows-Bb + Abamectin > Bt+ Spinosad > Bt + Abamectin > Bt + Neem oil> Bb + Lufenuron > Bt + Lufenuron> Bt + Buprofezin. Similarly in the third spray, the highest percentage reduction of infested twig over control was observed from the plots treated with Bb + Abamectin (98.33%). However Bt + Buprofezin (61.53%) provided the least percentage reduction of infested twig affected by bean aphid (Fig. 1). The efficacy rank of the IPM modules on (%) reduction of infested twig over control was as follows- Bb + Abamectin > Bt + Abamectin > Bt + Neem oil > Bt + Spinosad > Bb + Lufenuron > Bt + Lufenuron > Bt + Buprofezin.

Treatments

5 DAS

10 DAS

15 DAS

No. of healthy flower plot-1

No. of infested flower plot-1

%infestation

No. of healthy flower plot-1

No. of infested  flower plot-1

%infestation

No. of healthy flower plot-1

No. of  infested flower plot-1

%infestation

T1

55.00c

7 f

11.29

57.00c

6e

9.52

58.00c

5e

7.94

T2

52.00d

10d

16.13

53.00e

10c

15.87

54.00e

9c

14.29

T3

58.00b

6g

9.38

59.00b

5e

7.81

60.00b

4ef

6.25

T4

54.00c

8e

12.90

56.00d

8d

12.5

57.00d

7d

10.94

T5

50.00e

12c

19.35

51.00f

11c

17.74

50.00f

10c

16.67

T6

60.00a

4h

6.25

62.00a

3f

4.62

63.00a

3f

4.55

T7

48.00f

13b

21.31

49.00g

13b

20.97

49.00g

11b

18.33

T8

45.00g

14a

23.73

46.00h

16a

25.81

47.00h

18a

27.69

Level of significance

*

**

 

**

**

 

*

*

CV%

5.41

9.00

 

11.87

7.85

 

10.64

8.10

Table 4 – Effect of IPM modules on the infestation of flower at different days after 1st spray

Effect of IPM modules on the infestation of flower caused by A. craccivora

After 1st spray, the lowest percentage of infested flower was found at Bb + Abamectin sprayed plot (6.25%) followed by Bt + Abamectin (9.38%) at 5 DAS. The highest percentage of infested flower was observed from control (23.73%) (Table 4). At 10 DAS, the lowest percentage of infested flower was seen at Bb + Abamectin sprayed plot (4.62%) followed by Bt + Abamectin (7.81%). The highest percentage of infested flower was observed from control (25.81%) (Table  4). AT 15 DAS, the lowest percentage of infested flower was seen at Bb + Abamectin sprayed plot (4.55%) followed by Bt + Abamectin (6.25%). The highest percentage of infested flower was observed from control (27.69%).

After 2nd spray, the lowest percentage of infested flower was observed at Bb + Abamectin sprayed plot (2.33%) followed by Bt + Abamectin (5.37%) at 5 DAS. The highest percentage of infested flower was observed from control (34.12%) (Table 5). At 10 DAS, the lowest percentage of infested flower was recorded at Bb + Abamectin sprayed plot (1.81%) followed by Bt + Abamectin (3.79%). The highest percentage of infested flower was observed from control (38.82%) (Table 5). Similarly at 15 DAS, the lowest percentage of infested flower was seen at Bb + Abamectin sprayed plot (1.73%) followed by Bt + Abamectin (4.29%). The highest percentage of infested flower was observed from control (43.39%).

Treatments

5 DAS

10 DAS

15 DAS

No. of healthy flower plot-1

No. of infested flower plot-1

%infestation

No. of healthy flower plot-1

No. of infested  flower plot-1

%infestation

No. of healthy flower plot-1

No. of  infested flower plot-1

%infestation

T1

62.66c

4.67f

6.93

67.00b

3.67e

5.19

69.00b

4.33cd

5.90

T2

53.00e

6.00e

10.17

56.00d

5.00d

8.19

58.00e

4.00d

6.45

T3

64.67b

3.67g

5.37

67.67b

2.67e

3.79

67.00c

3.00d

4.29

T4

57.67e

9.00c

13.49

60.33c

8.00b

11.71

60.67d

7.00b

10.34

T5

48.00f

7.67d

13.78

49.67e

6.67c

11.83

52.00f

5.67bc

9.83

T6

70.00a

1.67h

2.33

72.00a

1.33f

1.81

75.33a

1.33e

1.73

T7

43.00g

10.00b

18.87

45.00f

7.33bc

14.00

47.00g

7.00b

12.96

T8

38.00h

19.67a

34.12

34.67g

22.00a

38.82

30.00h

23.00a

43.39

Level of significance

*

**

**

**

**

*

CV%

6.91

6.64

6.75

9.80

8.24

12.47

Table 5 – Effect of IPM modules on the infestation of flower at different days after 2nd spray

T1 = Bt + Spinosad, T2= Bb + Lufenuron, T3 = Bt + Abamectin, T4 = Bt + Neem oil, T5 = Bt + Lufenuron, T6 = Bb+ Abamectin, T7= Bt + Buprofezin and T8= untreated control; In column, means followed by different letters are significantly different; * & ** Mean significant at 5% & 1% level of probability, respectively.

T1 = Bt + Spinosad, T2= Bb + Lufenuron, T3 = Bt + Abamectin, T4 = Bt + Neem oil, T5 = Bt + Lufenuron, T6 = Bb+ Abamectin, T7= Bt + Buprofezin and T8= untreated control; In column, means followed by different letters are significantly different; * & ** Mean significant at 5% & 1% level of probability, respectively

After 3rd spray, the lowest percentage of infested flower was noticed at Bb + Abamectin sprayed plot (1.29%) followed by Bt + Abamectin (3.03%) at 5 DAS. The highest percentage of infested flower was observed from control (45.12%) (Table 6). At 10 DAS, the lowest percentage of infested flower was seen at Bb + Abamectin sprayed plot (0.91%) followed by Bt + Abamectin (2.17%).

Treatments

5 DAS

10 DAS

15 DAS

No. of healthy flower plot-1

No. of infested flower plot-1

%infestation

No. of healthy flower plot-1

No. of infested  flower plot-1

%infestation

No. of healthy flower plot-1

No. of  infested flower plot-1

%infestation

T1

67.00b

3.00cd

4.29

60.00b

1.33c

2.17

58.00b

2.00c

3.33

T2

55.00e

4.33bc

7.29

50.00d

3.00b

5.66

47.00e

2.67bc

5.38

T3

64.00c

2.00de

3.03

60.00b

1.33c

2.17

54.67c

0.67de

1.21

T4

57.00d

4.67b

7.57

52.00c

3.67b

6.59

50.00d

3.33b

6.24

T5

48.00f

4.0bc

7.69

45.00e

3.00b

6.25

42.67f

2.67bc

5.88

T6

76.33 a

1.00e

1.29

73.00a

0.67c

0.91

70.00a

0.33e

0.47

T7

44.67g

5.00b

10.07

39.67f

3.00b

7.03

37.00g

1.67cd

4.32

T8

30.00h

24.67a

45.13

25.00g

20.00a

44.44

22.67h

17.00a

42.85

Level of significance

**

**

**

*

**

*

CV%

10.0

8.83

7.83

6.45

8.67

9.52

Table 6 – Effect of IPM modules on the infestation of flower at different days after 3rd spray

T1 = Bt + Spinosad, T2= Bb + Lufenuron, T3 = Bt + Abamectin, T4 = Bt + Neem oil, T5 = Bt + Lufenuron, T6 = Bb+ Abamectin, T7= Bt + Buprofezin and T8= untreated control; In column, means followed by different letters are significantly different; * & ** Mean significant at 5% & 1% level of probability, respectively

The highest percentage of infested flower was observed from control (44.44%) (Table 6). Similarly, at 15 DAS, the lowest percentage of infested flower was seen at Bb + Abamectin sprayed plot (.47%) followed by Bt + Abamectin (1.21%). The highest percentage of infested flower was observed from control (42.85%) (Table 6).

The highest percentage reduction of infested flower over control was observed from the plots treated with Bb + Abamectin (83.6%) in first spray. However Bt + Buprofezin (33.8%) provided the least percentage reduction of infested flower over control (Fig. 2). The efficacy rank of the IPM modules on (%) reduction of infested flower over control was as follows- Bb + Abamectin Bt + Abamectin >Bt + Spinosad > Bt + Neem oil> Bb + Lufenuron> Bt + Lufenuron > Bt + Buprofezin. After second spray, the highest percentage reduction of infested flower over control was observed from the plots treated with Bb + Abamectin (96.01%). However, Bt + Buprofezin (70.13%) provided the least percentage reduction of infested flower over control (Fig. 2). The efficacy rank of the IPM modules on (%) reduction of infested flower over control was as follows- Bb + Abamectin > Bt + Abamectin > Bt + Spinosad > Bb + Lufenuron > Bt + Lufenuron > Bt + Neem oil > Bt + Buprofezin.

Figure 2 – Effect of IPM modules on the reduction (%) of infested flower over control at 1st, 2nd, and 3rd sprays

The highest percentage reduction of infested flower over control was observed from the plots treated with Bb + Abamectin (98.9%). However Bt + Neem oil (85.43%) provided the least percentage reduction of infested flower over control (Fig. 2). The efficacy rank of the IPM modules on (%) reduction of infested flower over control was as follows- Bb + Abamectin > Bt + Abamectin > Bt + Spinosad > Bb + Lufenuron > Bt + Lufenuron > Bt + Neem oil > Bt + Buprofezin.

Effect of IPM modules on the infestation of pod caused by A. craccivora

In case of 1st spray, at 5 DAS, the lowest percentage of infested pod was seen at Bb + Abamectin sprayed plot (7.89%) followed by Bt + Abamectin (11.76%). The highest percentage of infested pod was observed from control (24.53%) (Table 7). At 10 DAS, the lowest percentage of infested pod was seen at Bb + Abamectin sprayed plot (6.49%) followed by Bt + Abamectin (10.14%). The highest percentage of infested pod was observed from control (24.07%) (Table 7). Similarly, at 15 DAS the lowest percentage of infested pod was seen at Bb + Abamectin sprayed plot (5.13%) followed by Bt + Abamectin (8.57%). The highest percentage of infested pod was observed from control (27.08%).

Treatments

5 DAS

10 DAS

15 DAS

No. of healthy pod plot-1

No. of infested pod plot-1

%infestation

No. of healthy pod plot-1

No. of infested pod plot-1

%infestation

No. of healthy pod plot-1

No. of infested pod plot-1

%infestation

T1

56.00c

9.00e

13.85

56.00c

9.00e

13.85

56.00c

9.00e

13.85

T2

50.00e

10.00d

16.67

50.00e

10.00d

16.67

50.00e

10.00d

16.67

T3

60.00b

8.00f

11.76

60.00b

8.00f

11.76

60.00b

8.00f

11.76

T4

52.00d

10.00d

16.13

52.00d

10.00d

16.13

52.00d

10.00d

16.13

T5

48.00f

11.00c

18.64

48.00f

11.00c

18.64

48.00f

11.00c

18.64

T6

70.00a

6.00g

7.89

70.00a

6.00g

7.89

70.00a

6.00g

7.89

T7

45.00g

12.00b

21.05

45.00g

12.00b

21.05

45.00g

12.00b

21.05

T8

40.00h

13.00a

24.53

40.00h

13.00a

24.53

40.00h

13.00a

24.53

Level of significance

**

**

**

**

**

**

CV%

6.98

4.68

6.98

4.68

6.98

4.68

Table 7 – Effect of IPM modules on the infestation of pod at different days after 1st spray

T1 = Bt + Spinosad, T2= Bb + Lufenuron, T3 = Bt + Abamectin, T4 = Bt + Neem oil, T5 = Bt + Lufenuron, T6 = Bb+ Abamectin, T7= Bt + Buprofezin and T8= untreated control; In column, means followed by different letters are significantly different. * & ** Mean significant at 5% & 1% level of probability, respectively

After 2nd spray, at 5DAS, the lowest percentage of infested pod was seen at Bb + Abamectin sprayed plot (2.56%) followed by Bt + Abamectin (5.72%). The highest percentage of infested pod was observed from control (29.62%) (Table8). At 10 DAS, after 2nd spray, the lowest percentage of infested pod was observed at Bb + Abamectin sprayed plot (2.42%) followed by Bb + Lufenuron (2.98%). The highest percentage of infested pod was noticed from control (40%) (Table 8). And again, the lowest percentage of infested pod was found from Bb + Abamectin sprayed plot (2.16%) followed by Bt + Spinosad (4.26%) at 15 DAS. The highest percentage of infested pod was observed from control (48%).

Treatments

5 DAS

10 DAS

15 DAS

No. of healthy pod plot-1

No. of infested pod plot-1

%infestation

No. of healthy pod plot-1

No. of infested pod plot-1

%infestation

No. of healthy pod plot-1

No. of infested pod plot-1

%infestation

T1

39.67c

2.67de

6.31

43.00d

2.67cde

5.85

45.00  c

2.00de

4.26

T2

35.00e

3.67cd

9.49

97.67a

3.00cd

2.98

40.67e

3.00cd

6.87

T3

44.00b

2.67de

5.72

48.33c

2.00de

3.97

50.67b

2.33de

4.39

T4

37.67d

4.00cd

9.60

40.00e

3.33cd

7.69

43.00d

2.67d

5.85

T5

27.33f

5.00bc

15.47

31.67f

4.00bc

11.21

35.00f

4.00bc

10.25

T6

50.67a

1.33e

2.56

53.67b

1.33e

2.42

60.00a

1.33e

2.16

T7

25.00g

6.00b

19.35

28.00g

5.33b

15.99

30.67g

4.67b

13.21

T8

19.00h

8.00a

29.62

15.00h

10.00a

40

13.00  h

12.00a

48

Level of significance

**

*

**

*

*

*

CV%

9.31

8.51

9.20

9.49

8.75

6.91

Table 8 – Effect of IPM modules on the infestation of pod at different days after 2nd spray

T1 = Bt + Spinosad, T2= Bb + Lufenuron, T3 = Bt + Abamectin, T4 = Bt + Neem oil, T5 = Bt + Lufenuron, T6 = Bb+ Abamectin, T7= Bt + Buprofezin and T8= untreated control; In column, means followed by different letters are significantly different. * & ** Mean significant at 5% & 1% level of probability, respectively.

Treatments

5 DAS

10 DAS

15 DAS

No. of healthy pod plot-1

No. of infested pod plot-1

%infestation

No. of healthy pod plot-1

No. of infested pod plot-1

%infestation

No. of healthy pod plot-1

No. of infested pod plot-1

%infestation

T1

35.0 c

1.33 bc

3.66

30.00 c

1.33 cd

4.25

28.00c

.33cde

4.53

T2

31.33d

2.33b

6.92

28.00 d

1.67bcd

5.63

24.67d

0.67de

2.64

T3

40.0 b

1.33bc

3.22

38.00 b

1.33cd

3.38

35.00b

0.67de

1.88

T4

35.0  c

0.67c

1.88

30.00c

1.33cd

4.25

27.67c

.67bcd

5.69

T5

29.0 e

1.67bc

5.45

28.00d

2.00bc

6.67

25.0d

2.33bc

8.53

T6

51.0  a

0.67c

1.29

44.67 a

0.33d

0.74

42.0a

0.33e

0.78

T7

21.0  f

2.33b

9.99

18.00e

3.00b

14.29

15.0e

2.67b

15.11

T8

8.0   g

9.67a

54.73

5.00f

11.00a

68.75

3.0f

10.0a

76.92

Level of significance

*

*

**

*

*

*

CV%

7.63

6.90

7.70

12.85

10.05

6.81

Table 9 – Effect of IPM modules on the infestation of pod at different days after 3rd spray

T1 = Bt + Spinosad, T2= Bb + Lufenuron, T3 = Bt + Abamectin, T4 = Bt + Neem oil, T5 = Bt + Lufenuron, T6 = Bb+ Abamectin, T7= Bt + Buprofezin and T8= untreated control; In column, means followed by different letters are significantly different. * & ** Mean significant at 5% & 1% level of probability, respectively

After 3rd spray, the lowest percentage of infested pod was recorded at Bb + Abamectin sprayed plot (1.29%) followed by Bt + Neem oil (1.88%) at 5 DAS. The highest percentage of infested pod was observed from control (54.73%) (Table 9). At 10 DAS, the lowest percentage of infested pod was seen at BB + Abamectin sprayed plot (0.74%) followed by Bt + Abamectin (3.38%) but the highest percentage of infested pod was observed from control (68.75%) (Table 9). Similarly at 15 DAS, the lowest percentage of infested pod was seen at Bb + Abamectin sprayed plot (0.78%) followed by Bt +Abamectin (1.88%). The highest percentage of infested pod was observed from control (76.92%).

Figure 3 – Effect of IPM modules on the reduction (%) of infested pod over control at 1st, 2nd, and 3rd sprays

The highest percentage reduction of infested pod over control was observed from the plots treated with Bb + Abamectin (81.68%) in first spray. However Bt + Buprofezin (32.31%) provided the least percentage reduction of infested pod infested by bean aphid (Fig. 3). The efficacy rank of the IPM modules on (%) reduction of infested flower over control was as follows- Bb + Abamectin > Bt + Abamectin > Bt + Spinosad > Bt + Neem oil > Bb + Lufenuron > Bt + Lufenuron > Bt + Buprofezin.  The highest percentage reduction of infested pod over control was observed from the plots treated with Bb + Abamectin (95.5%). However Bt + Buprofezin (72.47%) provided the least percentage reduction of infested pod infested by bean aphid (Fig. 3). The efficacy rank of the IPM modules based on (%) reduction of infested flower over control was as follows-Bb + Abamectin > Bt + Spinosad > Bt + Abamectin> Bt + Neem oil > Bb + Lufenuron > Bt + Lufenuron > Bt + Buprofezin. The highest percentage reduction of infested pod over control was observed from the plots treated with Bb + Abamectin (98.99%). However Bt + Buprofezin (80.35%) provided the least percentage reduction of infested pod affected by bean aphid (Fig. 3).The efficacy rank of the IPM modules on (%) reduction of infested flower over control was as follows- Bb + Abamectin > Bt + Abamectin > Bb + Lufenuron > Bt + Spinosad > Bt + Neem oil > Bt + Lufenuron > Bt + Buprofezin.

Effect of IPM modules on the yield (ton ha-1) of marketable pod

Treatments

Yield (ton ha-1)

Yield increase (%)

T1

7.63c

55.18

T2

6.31e

45.80

T3

9.43b

63.73

T4

6.45d

46.98

T5

5.39f

36.55

T6

12.46a

72.55

T7

4.65g

26.45

T8

3.42h

Level of Significance

*

CV (%)

6.78

LSD

1.13

Table 10 – Effect of IPM modules on the yield (ton ha-1) of marketable pod

T1 = Bt + Spinosad, T2= Bb + Lufenuron, T3 = Bt + Abamectin, T4 = Bt + Neem oil, T5 = Bt + Lufenuron, T6 = Bb+ Abamectin, T7= Bt + Buprofezin and T8= untreated control; In column, means followed by different letters are significantly different. * Means significant at 5% level of probability

The results revealed that all IPM modules could increase marketable pod yield (ton ha-1) of country bean significantly as compared to control. Statistically significant variation was observed in respect of yield at different modules in the present study. Bb +Abamectin showed the highest (12.46 ton ha-1) yield which was significantly different from other treatments used in the experiment whereas the lowest yield was recorded from untreated control plots (3.42 ton ha-1). The IPM module comprising Bt + Abamectin also showed a very good yield performance among the modules tested.

Discussion

From the present study of developing microbial insecticide based IPM modules on the aphid infestation it was observed that aphid infestation changed significantly on the twig, flower, and pod at different sprays and time intervals. The highest percentage of reduction of infestation over control was found in Bb + Abamectin treated plants which was followed by Bt + Abamectin .  Similarly, the highest yield and percentage yield increase of marketable pod were also found from the plots treated with Bb + Abamectin which was also followed by Bt + Abamectin . Based on different parameters was clearly observed that Beauveria bassiana and Abamectin were very effective to manage the bean aphid in the field.  Similar findings were reported by 11 where they stated that Abamectin could control aphids about 98.90% after five days of spraying. Similarly, it was reported that Abmectin 1.8EC @ 0.5ml/l was highly effective against aphid and thrips on chilli in the field12. Besides, it has been explained that Abamectin showed the good performance against aphid infestation in the field13. It was stated that nano-formulated Abamectin had very good effect against the pea aphid. They also explained that these results are expected to contribute to the application of solvent-free nano-formulated pesticides that comply with the integrated pest management (IPM) strategies14. Abamectin was found very effective to reduce the aphid (Aphis gossypii)   infestation on tomato in the field and subsequently to increase the yield of tomato 15. These above reports are more or less in the line with the findings of the present research which support the toxic effect of Abamectin for managing aphid and increase of marketable pod yield of the country bean. In another report it has been stated that Beauveria bassiana @ 3.33 ml/l was very effective on the mortality of mustard aphid both in leaf dip and spray methods in the laboratory16. This finding supports the results of the present research where Beauveria bassiana was also very effective in IPM module to manage the aphid infestation and subsequently the yield of marketable pod of country bean.

Conclusion

All the biorational insecticides based IPM modules tested were significantly effective against the aphid infesting country bean. But the module comprising Bb + Abamectin showed the best performance based on the efficacy against the aphid infestation as well as yield of marketable pod. Therefore, this module might be recommended for the management of bean aphid by the farmers after regional trial throughout the country.

Acknowledgments

The authors would like to thanks to the Ministry of Education, Government of the People’s Republic of Bangladesh for providing the fund to conduct this nice research work under a project.

References

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  2. Statistical Year book of Bangladesh, Bangladesh Bureau of Statistics, Government of the People’s Republic of Bangladesh, Dhaka, 2017.
  3. Alam MZ, Ahmed A, Alam S, Islam MA. A review of Research Division of Entomology (1947-1964). Agriculture Information Service, 3, R. K. Mission Road, Dhaka-3,1964 76p.
  4. Minks AK, Harrewijn P. Aphid pathogens. In: Minks AK. Harrewijn P (eds) Aphids their biology, natural enemies and control.Vol.2B. Elsevier. Amsterdam, Netherlands. 1988 pp 5-7.
  5. Dixon AFG. Parthenogenetic reproduction and rate of increase in aphid. 1987 pp. 269-287.
  6. Singh SR, Allen DJ. Pests, diseases, resistance and protection of Vigna unguiculata (L.) Walp. Advances in legumes science.   J.  Summerfield and H.  A. Bunting. (eds.) London: Royal Botanical Gardens, and Ministry of Agriculture, Fisheries and Food. 1980 419-443
  7. Attle AA, El- heneidy AH, Elkady EA. Studies on the aphid, Aphis craccivora in Bull. De-la-Societe Entomologique-d’Egypte, 1987 66: 319-324.
  8. Islam MS. Genetic diversity, combining ability and heterosis in Hyacinth bean [(Lablab purpureus (L) Sweet]. A PhD dissertation submitted to Bangabandhu Sheikh Mujibur Rahman Agricultural University, Salna, Gazipur. Bangladesh, 2008 190 p.
  9. Sharma HC, Singh M, Residual toxicity of insecticides on cabbage caterpillar (Pieris brasicae) and their dissipation on cauliflower. Indian J Agric Sci. 1993 63(1): 59-63.
  10. Rahman MM, Sampa MSA. Combined effects of Bradyrihizobial strain municipal solid waste compost and fertilizers on nodulation, N content and uptake of soybean. J Environ Sci Nat Res. 2012 5(2): 85-90.
  11. Sun Y, Xue M, Zhang X, Zhao HP, Li ZX. Population dynamics and control techniques of aphids on honeysuckle. Zhongguo Zhong Yao Za Zhi. 2013 8(21): 3676-80.
  12. Sujay YH, Giraddi1 RS, Udikeri SS. Efficacy of new molecules and botanicals against chilli (Capsicum annuum ) pests. Madras Agric J. 2015 102 (10-12): 348-352.
  13. Saad AS, Massoud MA, Abdel-Mgged AA, Mourad AK, et al. An approach for IPM programme to control sucking pests infesting garden bean plants (Phaseolus vulgaris) in Egypt. Commum Agric Appl Biol Sci. 2007 72(3): 565-581.
  14. Sun C, Yu M, Zeng Z, Francis F, et al. Biocidal activity of polylactic acid-based nano-formulated Abamectin on Acyrthosiphon pisum(Hemiptera: Aphididae) and the aphid predator Adalia bipunctata(Coleoptera: Coccinellidae). PLoS ONE 2020 15(2): e0228817. https://doi.org/10.1371/journal.pone.0228817.
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  16. Khanal D, Maharjan S, Lamichhane J, Neupane P, et al. Efficacy of biorational compounds against mustard aphid (Lipaphis erysimi Kalt.) and English grain aphid (Sitobion avenae Fab.) under laboratory conditions in Nepal. Adv Agric. 2020 pp1-7.

Timeline

Keywords

  • Bacillus thuringiensis
  • Beauveria bassiana
  • Abamectin
  • Buprofzin
  • Lufenuron
  • Spinosad
  • Neem