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Effect Of Sowing Dates Of Different Wheat Varieties On Aphid Population And Its Natural Enemies

Introduction

Wheat is a staple food for the people of Pakistan and provides 72% of calories and protein in a balanced diet (CIMMYT, 1989). Pakistan is the 8th largest grower of wheat in the world. (Anonymous, 2017). In Pakistan, about 25492 thousand tons of wheat is produced from an area of about 8950 thousand hectares While in the Punjab province the area under wheat crop was 6917 thousand hectares and its production remained 19526.67 thousand ton during 2016-17. (Anonymous, 2017). The wheat crop has undergone extensive damage and stress that disrupts its normal functioning and development at all phases.

The wheat crop is often infested with aphids during the growing season when both adults and nymphs take on a heavy load by absorbing cell sap that reduces plant energy. The full leaves turn brown, wither, and wear a silk look. Some species have toxic saliva, and a strong infestation can kill young shoots. Honeydew emissions are often very common and sooty fungi are often associated with aphid infections that eventually affect the level of photosynthesis in plants. Poor wheat yield is mainly due to its instability from aphid infestation. Aphids are the worst crop for wheat harvest. They can grow very quickly under favourable conditions on leaves, stems, and inflorescence. The infection causes severe deformation of the leaves and inflorescence and can significantly reduce yields through direct feeding. Four species of aphids have been reported to be abundant in Pakistan (Hashmi et al. 1983). Although most insects attack wheat (Triticumaestivum L.) in Pakistan, the main damage is caused by lice.

Aphids cause loss of yield directly (35-40%) by ingesting plant milk or indirectly (20-80%) by transmitting bacterial and fungal infections (Aslam et al 2005). The size of the aphid population also depends on the abiotic characteristics (Aheer GM et al 2007, Wains MS 2008). During the spring (February-March) the number of aphids increases, at the same time biocontrol agents such as Coccinellids also increase as a natural check in the insect (Khan et al. 2011) Reducing dependence on pesticides, traditional practices such as Carson / canola planting the number of people eating some, changing the sowing days can help. Therefore, this study is designed to determine the effect of planting days on the formation of lice population in wheat so that the planting date coincides to reduce the penetration of aphids.

Material & Methods:

This study was organized at Adaptive Research Farm, Sheikhupura. The experiment was comprised of four treatments and deliberated in Randomized Complete Block Design (RCBD) with three repeats for all treatments. Treatments were four different dates of sowing viz. 10.11.2020, 20.11.2020, 30.11.2020 and 10.12.2020. Five wheat varieties were sown in each block of sowing dates i.e., Galaxy-2013, Ujala- 2016, Faisalabad-2008, Johar 2016, and Punjab- 2011. The area of the trial was 2024m2. Data of aphid’s infestation was recorded after every seven days from the incidence of pests. 

For each sample day, 10 wheat plants were selected randomly for each plot and the number of aphids per grower for each crop and natural enemies in the five plants was counted. All the agronomic practices remained the same for each treatment. Data concerning abiotic factors (RH% and °C) was measured from an observatory of Agriculture Ext. department. The data were based on variance analysis and comparison was made for mean values with the LSD variance test at the 0.05 probability level (Steel and Torrie., 1980).

Result and Discussion:

Table : 1.Germination Counts(m-2) of different varieties sown at different times

VarietiesDOS 1DOS 2DOS 3DOS 4
V1204.67205.33211.33206.00
V2215.00214.00214.33212.00
V3213.00224.67219.33216.33
V4214.00215.33226.67219.00
V5215.33215.00214.67213.00
LSD7.175.623.474.15

1st date of sowing

Table: 2 Different counts of aphid Population per tiller on different wheat varieties sown on 10th November 2020: 

Varieties Sampling dates
4/2/2111/2/2118/2/2125/2/214/3/2111/3/2118/3/2125/3/21
Galaxy 2013
0.66a
  3.00b 

4.66a
11.00a  
10.33b

40.00a

48.33 ab

11.33a
Ujala 2016
1.66a

5.00a

4.33ab

7.33a

14.00ab

43.33a

40.00ab

1.33a
Punjab 2011
2.00a

4.00ab

3.66ab

10.66a

19.66a

38.33a

50.00a

2.00a
Anaj 2016
1.00a

2.33b

3.66ab

8.33a

20.66a

49.00a

45.00ab

1.33a
Faisalabad 2008
1.33a

3.33ab

3.00b

11.00a
19.66a

47.66a

38.33b

1.33a
LSD (p5%)1.491.681.536.756.9211.3310.740.97

Mean aphid Population per tiller of eight counts on different wheat varieties sown on 10.11.2020:

Varieties Aphids’ population per tiller
Galaxy-201315 a
Ujala 201615 a
Punjab 201115a
Anaj 201616 a
Faisalabad 200816 a
LSD (p5%)2.77

2nd date of sowing:

Table: 3 Different counts of aphid Population per tiller on different wheat varieties sown on 20th November 2020:

Varieties Sampling dates
4/2/2111/2/2118/2/2125/2/214/3/2111/3/2118/3/2125/3/21
Galaxy 2013
1.33a  

2.00a 

3.33a

5.66ab  

13.33ab  

 34.00b  

 45.00a  
  2.33ab  

Ujala 2016

0.66a

1.33a

4.66a

10.66ab

17.00ab

39.66 ab

39.33a

3.00a
Punjab 2011
1.00a

2.33a

5.66a

8.00ab

12.00b

41.00ab

45.66a

1.33bc

Anaj 2016

1.66a

1.66a

4.33a

4.66b

20.66a

33.33b

43.33a

1.66bc
Faisalabad 2008
1.00a

1.66a

4.00a

12.00a

11.00b

45.33a

36.66a

1.00c
LSD (p5%)1.551.433.486.427.4110.5916.641.16

Mean aphid Population per tiller of eight counts on different wheat varieties sown on 20.11.2020:

Varieties Aphids’ population per tiller
Galaxy-201313 a
Ujala 201615 a
Punjab 201115 a
Anaj 201614 a
Faisalabad 200814 a
LSD (p5%)2.35

3rd date of sowing:

Table: 4     Different counts of aphid Population per tiller on different wheat varieties sown on 30th November 2020:

Varieties Sampling dates
4/2/2111/2/2118/2/2125/2/214/3/2111/3/2118/3/2125/3/21

Galaxy 2013

 0.66a

1.00b
  1.66ab
 3.00a 
  9.33b
 45.00a

55.00a
  2.66ab 

Ujala 2016

0.66a

1.00b

2.33ab

4.00a

16.33a

32.66b

32.66b

3.66a

Punjab 2011

0.33a

2.00a

3.00a

2.66a

6.00c

46.66a

26.33b

1.33b
Anaj 2016
1.00a

1.66ab

1.33b

3.33a

11.33b

21.33c

50.66a

2.33ab
Faisalabad 2008
0.33a

1.00b

2.00ab

3.00a

11.00b

30.33b

24.66b

1.33b
LSD (p5%)1.00
0.971.551.752.948.2016.592.06

Mean aphid Population per tiller of eight counts on different wheat varieties sown on 30.11.2020:

Varieties Aphids’ population per tiller
Galaxy-201314 a   
Ujala 201612 b
Punjab 201111 b
Anaj 201612 b
Faisalabad 20089 b
LSD (p5%)2.67

4th date of sowing:

Table: 5 Different counts of aphid Population per tiller on different wheat varieties sown on 10th December 2020:

Varieties Sampling dates
4/2/2111/2/2118/2/2125/2/214/3/2111/3/2118/3/2125/3/21

Galaxy 2013

 0.00a
  1.66a
1.66a  
  4.33a
3.33d

64.66a

 47.33a

 5.00a 
Ujala2016
0.33a

0.00c

1.00ab

3.00ab

7.00ab

17.33b

27.00b

5.33a
Punjab 2011
0.00a
1.00b0.66b2.33b4.33cd85.00a42.33ab1.33b
Anaj 20160.33a1.00b1.00ab2.33b6.00bc25.00b34.00ab1.33b
Fsd- 20080.33a0.66b0.66b4.66a8.66b30.33b25.66b1.33b
LSD (p5%)0.940.590.841.982.2523.1518.351.41

Mean aphid Population per tiller of eight counts on different wheat varieties sown on 10.12.2020:

Varieties Aphids’ population per tiller
Galaxy-201316a   
Ujala 20168 b
Punjab 201117a
Anaj 20169 b
Faisalabad 20089 b
LSD (p5%)3.86

Table: 6. Comparison of mean aphid Population per tiller on different wheat varieties sown at different times 

VarietiesNo. of aphids per tillers (Ave. of eight counts) at the different date of sowing
01.11.202010.11.202020.11.202030.11.2020
Galaxy-201315 a13 a14 a   16 a   
Ujala-201515 a15 a12 b8 b
Punjab 201115a15 a11 b17 a
Anaj-201616 a14 a12 b9 b
Faisalabad -200816 a14 a9 b9 b
LSD (p5%)2.772.352.673.86

Table: 7. Metrological data during wheat grown period at AR Farm Sheikhupura

MonthsMax.TempMin.TempHumidityRainfall
February18.116.4768.63.01
March22.5411.2552.10.29

Table: 8. Average predators per five plants of eight counts at different sowing dates on wheat varieties

Var.Dos1DOS2DOS3DOS4
V13.373.752.872.12
V23.373.622.252.5
V33.252.752.622.62
V42.752.5221.75
V52.752.371.752.12

Data presented in table- 2, 3, 4 & 5 showed that aphids were seen initially on 4 February on the crop sown on 10.11.2020, and a maximum of 2 aphids per tiller was recorded on the varieties Punjab 2011 but no aphid was seen in the rest of planting dates at that time. During the recording of data on 11.02.2021, the population of aphids was noted on all the dates of sowing but a maximum of 5.00 and minimum of 1.00 aphids per tiller was counted in planting dates 1st date of sowing and last date of sowing, respectively.

During the season it was noted that the aphid population begins to expand promptly from mid-February to mid of March on the planting dates 10.11.2020 & 20.11.2020 but on the other planting dates, the increasing trend of aphid population was recorded from the end of Feb to mid-March.

After the sixth count decreasing trend of aphid population was noted on the first two planting dates it might be due to the turning of crop towards maturity, increasing trend of predators, and rise in temperature while on the 3rd and 4th planting dates exponential increase in population was noted during 7th count because crop stage was favorable to aphids and after 7th count, its population started to decrease due to increasing trend of predators and rise in temperature.

Maximum aphid population on 10-20 November the grown crop was noticed from 25th  February to 18th March  (Table 2,3) while on the third and fourth planting dates maximum aphid populace was observed from March 4 to 18. On late sown (10.12.2020) wheat crop, highest aphid populace was observed in comparison with timely sown crop 10-20 November. 

This is because in those days the weather allowed for the development of insects. The temperature in the study area ranged from 5.9 oC to 22.54 oC (table 6) during the experimental time. These results are consistent with those of Abou-Elhagag and AbdeHafez (1998), who disclosed that the number of aphids gradually increased by 3 weeks in February. Bhambrro (2002) also told that the aphid reproduces at a rapid rate in cold conditions and reaches its peak in February-March when the ears begin to ripen.

In the current study, the aphid count has dropped since the end of March and thoroughly faded in the first week of April. This may be due to the escalated temperature in April, the maturation of plants, and possibly the emergence of predators. Abou-Elhagag and Abdel-Hafez (1998) observed that daily temperatures, natural enemies, and related humidity play a critical role in controlling the aphid value in a wheat field. Zou et al. (2002) also reported that natural enemies of insects could play a key role in lessening the insect numbers.

Conclusion:

In conclusion, it is presumed that the aphid value was higher in early sown plants and the lowest aphid value was seen in late sowing. This specified that changing the date of sowing of wheat will affect aphid infestations. Ideally, wheat in Sheikhupura should be planted in the first and second week of November to keep away from severe aphid attacks.

Muhammad Atif1, Muhammad Haris2, Syed Jahanzaib Rasool3, Iqra Laraib

  1. School of Soil and  water conservation, Beijing Forestry University, China; atifkhara69@gmail.com 
  2. School of Soil and  water conservation, Beijing Forestry University, China; harisagrarian@gmail.com 
  3. Department of Agronomy, China Agriculture University, China; syedjahanzaib640@gmail.com 

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