EFFECTS OF CARBOSULFAN ON THE BIOLOGY OF
BIRD CHERRY OAT APHID
*AHMAD S1, HERAN Z1, HANIF MS2, SYED AH3
1Institute
of Agricultural Sciences, University of the Punjab, Lahore, Pakistan
2Fodder
Research Institute Sargodha, Sargodha, Pakistan
3Department
of Agricultural Entomology, University of Agriculture Faisalabad, Pakistan
*Corresponding author: shahbaz.ahmad@iags.pu.edu.pk, Zainabhera29@gmail.com
Abstract
Aphids
are the most commonly occurring, destructive, sap sucking and serious threat to
cereal crops especially wheat (Triticum aestivum). Bird Cherry Oat aphid Rhopalosiphum
padi (L.), is one of the most important aphids on
T. aestivum which is one of the most consumed
food and a source of nutrition in Pakistan. It causes considerable yield loss
in wheat. Carbosulfan, a carbamate,
is of the most commonly used pesticide against R. padi.
The effects of Carbosulfan on generations of R. padi were performed under standard lab conditions by exposing
adult aphids to three different concentrations (1.4×10-7 ppm, 1.4×10-10 ppm,
1.4×10-13 ppm) of Carbosulfan
(Advantage® EC). Based on the results. All three
concentrations noticeably reduced the pre-adult survival rate. 1.4×10-13
significantly extended the development duration of 1st instar, 2nd instar and
3rd instar nymphs. 1.4×10-13 ppm also extended the total pre-adult period and female
longevity of R. padi. The total longevity was increased
by 1.4×10-10 ppm. However, the fecundity decreased
the most at 1.4×10-10 ppm. While the TPRP
and APRP increased the most at 1.4×10-13 ppm.
In the life table parameters, both the intrinsic
rate of increase (r) and the finite rate of increase (ƛ) decreased
at 1.4×10-7 ppm and 1.4×10-10 ppm, as well as the net reproductive rate (R0)
also decreased at 1.4×10-7 ppm and 1.4×10-10
ppm, while mean generation time (T) showed increase at 1.4×10-13 ppm.
Thus, at the concentrations of Carbosulfan tested
here, there were negative impacts on R. padi
fitness and biology by decreased pre-adult survival rate, λ, r,
and R0. The concentrations also slowed down the development
of some stages and extended T. My results would be helpful in assessing the
overall effects of Carbosulfan on R. padi and should be taken into consideration when use Carbosulfan as a seed dressing insecticide for management
of R. padi in wheat crop.
Keywords: Bird cherry oat
aphid, Rhopalosiphum padi, Triticum aestivum, cereals, Carbosulfan,
Introduction
Wheat
is a staple food in Pakistan satisfying 80% of dietary needs with 38% share in
caloric intake. Pakistan ranks eighth
in terms of production in the world and is presently reaping production of over
25 million tons due to consolidated efforts of the farmers, policymakers and
scientists. Over 152 varieties of wheat have been launched in Pakistan so far
and a significant number of share from Punjab in the last decade; Punjab (69), Sindh (25), KP (44), Baluchistan (8), and PARC (6),
respectively (Ahmad et al., 2017). Bird cherry-oat aphid, R. padi, is the most implicated aphid in the transmission
of the barley yellow dwarf virus, among cereal aphids (Watson and Mulligan,
1960) which can dangerously reduce the yield of cereals (Watson, 1959).
Bird
cherry oat aphid R. padi (L.),
is one of the most financially important aphids on wheat (Akhtar et al.,
2007). It is widely distributed over Europe, Asia, Africa and other countries
such as Mexico, Canada, Australia, Brazil and Uruguay (CABI, 2019). Aphids are
nearly transparent sucking insects with soft bodies. Aphids can induce premature
death of leaves and yellowing when they are present in sufficient numbers. They
secrete drops of sugary liquid known as "honeydew", which encourages
the development of sooty molds on the leaves and causes tiny scorch. The life
cycle of aphids involves wingless (apterous), sexual,
winged (slates), and asexual forms. The females of most aphid species reproduce
asexually (without being fertilized) when it feeds on cereals, giving rise to
nymphs rather than eggs (Prescot et al, 1986). Attack of aphids also reduce
canopy dry matter. Infestation of aphids also causes continuous yellowing in
wheat from tillering stage to the end of flowering
stage. Yellowing symptoms can be observed at the flower stage in wheat when
aphids feed for seven days (Roza-Gomes, 2008). R. padi damages plants both by removing their sap and by transmitting
plant viruses (Close and Lamb, 1961; Greene,
1966; Harper and Blakeley, 1968). Usually aphid feeding causes poor root
growth and a decrease in tiller number but in spring heavy infestations can
kill young plants (Russell, 1978). They can reduce grain yield, thousand-kernel
mass, and quality also (Rautapaa, 1968). Feeding during the seedling (2-leaf) stage causes largest
reductions in yield causing a yield loss upto 40-60%,
with mean densities of 10-20 aphids/tiller (Kantack
and Kieckhefer, 1979). Plant physiology is affected in different
ways by sieve diversion by numerous aphids, depending on the plant growth stage
at time of infestation. The most common reaction in fruit trees is twig
stunting due to reduced growth. Bad fructification in flowers is also a result
of aphid feeding (flower abortion). Fruits can be smaller if aphids’ colonies
develop later. Most of these injuries by aphids are ‘asymptomatic’ (Quisenberry and Ni 2007) Carbosulfan
has been observed to significantly lower the population of R. padi on wheat (Faheem et al., 2016). Carbosulfan has also been shown to cause highest population reduction when compared with other
insecticides such as imidacloprid, acetamiprid and thiamethoxam etc.
(Ahmad et
al., 2017). Hence, this approach was adopted to study the population
responses of R. padi when exposed to Carbosulfan. The main objective of the current study was to
gain a better understanding about how very low concentrations of Carbosulfan affect the development, reproduction, and
survival of R. padi.
Materials
and methods
Insects
R.
padi adults were collected from wheat fields
at Ayub Agricultural Research Institute
(coordinates), Faisalabad, Pakistan. Collection sites were selected based on
insecticide usage history, seed dressing history and varietal differences.
Field collected aphids before exposing, were kept in laboratory for few hours
to attain homogeneity and to ensure pathogen and ectoparasites
free culture.
Insecticide
Carbosulfan (Advantage®
20EC) by FMC® was used in the experiment.
Bioassay
Leaf
dip method was used for bioassay with some modifications (Sawicki
and Rice 1978). Insecticide solution was prepared by taking 5 µL amount of
insecticide from insecticide bottle and added in 250ml water to attain required
volume. Serial dilution was done to attain required concentrations. Experimental
design CRD was adapted under controlled lab conditions: 23 ± 1°C, 60 ± 10% relative humidity (RH). There were three
concentrations, every concentration had three replicates. Fresh leaves were
collected from wheat field at AARI, washed and cleaned. After that leaves were
cut in smaller sizes, dipped into insecticide solution and left to dry for 1-2
hours. The dried leaves were placed into Petri plates on filter papers. 30
insects were exposed at every concentration (1.4×10-7 ppm, 1.4×10-10 ppm,
1.4×10-13 ppm). Data was collected after
every 24 hours till 8-10 days. Every specimen of adult aphids and their newly
young ones were separated after 24 hours, one specimen
was kept into one petri plate to check proper effects
of the insecticide. The aphids were observed under microscope, the live aphids
were given fresh food and the dead aphids were disposed of.
Analysis
The
basic life parameter such as age-specific fecundity (mx),
age-specific survival rate (lx), age-specific maternity (lxmx), intrinsic rate of
increase (r), finite rate of increase (ƛ), mean generation
time (T), net reproductive rate (R0), TPRP and APRP
were calculated using the computer program TWOSEX-MS Chart (Chi, 2017).
Results
According
to biological parameters of R. padi (Table 1), 1.4×10-13 ppm could significantly increase the survival period
of 1st instar nymphs (N1), 2nd instar (N2) nymphs and 4th instar
(N4) nymphs. In contrast 1.4×10-10 ppm
significantly increased the survival period of 3rd nymph instar (N3). Total pre adult
period increased significantly in 1.4×10-13 ppm.
There was significant increase in pre-adult survival rate and the female
longevity at 1.4×10-13 ppm. However, total
longevity rose more at 1.4×10-10 ppm
(5.06±0.46) as compared to 1.4×10-7 ppm
(4.09±0.53) and 1.4×10-13 ppm (4.80±0.73).
According to (Table 2),
fecundity (9.45±1.99) was significantly increased at 1.4×10-13 ppm. The Total pre reproductive period (TPRP) and the Adult
pre reproductive period (APRP) increased the most at 1.4×10-13 ppm. However, there was a significant decrease in Total pre
reproductive period (TPRP) (6.78±0.28) and Adult pre reproductive period (APRP)
(0.11±0.11) at 1.4×10-7 ppm. The
reproductive duration of female aphids increased the most at 1.4×10-7
ppm. According to the life table parameters of R. padi (Table 3),
the mean generation time (T) at 1.4×10-13 ppm
(10.61±0.48) was longer as compared to 1.4×10-7 ppm
(9.15±0.92) and 1.4×10-10 ppm (9.37±1.39).
Net reproductive rate (R0) was significantly decreased by
1.4×10-7 ppm (1.66±0.55) and 1.4×10-10
ppm (1.18±0.33) in comparison to 1.4×10-13
ppm (2.6±0.84). The intrinsic rate of increase (r)
and Finite rate of increase (ƛ) of aphids at 1.4×10-7 ppm and at 1.4×10-10 ppm
was significantly reduced as compared to 1.4×10-13 ppm where they increased distinctively.
Table
1: Effect of different concentrations of carbosulfan
on preadult developmental duration, preadult survival and longevity of R. padi
|
Parameter (days) |
n |
1.4×10-7ppm |
N |
1.4×10-10ppm |
n |
1.4×10-13ppm |
|
N1 |
19 |
1.89±0.2 |
30 |
1.83±0.13 |
17 |
1.94±0.16 |
|
N2 |
14 |
1.93±0.13 |
20 |
1.7±0.15 |
12 |
2.00±0.25 |
|
N3 |
9 |
1.56±0.18 |
15 |
2.07±0.15 |
11 |
1.73±0.24 |
|
N4 |
9 |
1.67±0.33 |
11 |
1.55±0.21 |
11 |
2.36±0.20 |
|
Total pre-adult |
9 |
6.67±0.29 |
11 |
6.91±0.16 |
11 |
8.27±0.24 |
|
Pre-adult survival |
|
0.2±0.05 |
|
0.22±0.05 |
|
0.27±0.07 |
|
Female longevity |
9 |
10.22±0.62 |
11 |
10.27±0.3 |
11 |
12±1.26 |
|
Total longevity |
45 |
4.09±0.53 |
50 |
5.06±0.46 |
40 |
4.80±0.73 |
Where= N1-N4
indicates the 1st to 4th instar
nymphs of R. padi
Table 2: Effect of different concentrations of carbosulfan on fecundity and reproduction of R. padi
|
Parameter |
1.4×10-7ppm |
1.4×10-10ppm |
1.4×10-13ppm |
|
Fecundity (nymph/female) |
8.33±1.3 |
5.36±0.56 |
9.45±1.99 |
|
TPRP |
6.78±0.28 |
7.27±0.24 |
8.73±0.27 |
|
APRP |
0.11±0.11 |
0.36±0.15 |
0.45±0.16 |
|
Reproductive duration |
3.22±0.32 |
2.91±0.28 |
3.18±0.35 |
Where, TPRP= Total
pre-reproductive period, APRP= Adult pre-reproductive period
Table
3: Effect of different concentrations of carbosulfan
on life table parameters of R. padi
|
Parameter |
1.4×10-7ppm |
1.4×10-10ppm |
1.4×10-13ppm |
|
Mean generation time T (day) |
9.15±0.92 |
9.37±1.39 |
10.61±0.48 |
|
Net reproductive rate R0 (offspring/individual) |
1.66±0.55 |
1.18±0.33 |
2.6±0.84 |
|
Intrinsic rate of increase r (d-1) |
0.0557±0.0407 |
0.0176±0.0329 |
0.0900±0.0331 |
|
Finite rate of increase λ (d-1) |
1.0573±0.0419 |
1.0178±0.0329 |
1.0942±0.0357 |
Figure: 1. Age specific survival rate (lx),
age-specific fecundity (mx) and net
maternity (lxmx) of R.
padi were tested on different concentrations of carbosulfan
The age-specific fecundity, age-specific
survival rate and net maternity for each of the three treatments are shown in Fig. 1. At concentration 1.4×10-7
ppm there was significant decrease in the age
specific survival rate (lx), on the other hand the age-specific
fecundity rate (mx) showed some
fluctuation as it increased at one point but dropped and then increased again.
The age specific maternity (lxmx)
increased uniformly for some time but then started to fluctuate. At
concentration 1.4×10-11 ppm age-specific
survival rate (lx) of R.padi
decreased with the passage of time and age-specific fecundity (mx) rate showed minor fluctuations and
did not change drastically. The age specific maternity (lxmx)
displayed a flat curve. At concentration 1.4×10-14 ppm age-specific survival rate (lx) of
the aphids decreased but then became constant for some time and then slowly
decreased again, while the age-specific fecundity (mx)
rate showed large fluctuations. The age-specific maternity (lxmx)
increased drastically and then decreased periodically (Fig.1).
Discussion
Carbosulfan [2,3-dihydro-2 2-dimethylbenzofuran-7-yl (dibutylaminothio) methylcarbamate]
is a broad-spectrum carbamate pesticide which
inhibits the activity of acetylcholinesterase. It is used
to control mites, insects and nematodes by foliar, seed and soil treatment
applications, foliar pests can be controlled via systemic action by soil
applications, andthrough direct conta
ct or stomach ingestion is said to be effective (FAO/WHO
1984), 1984).Carbosulfan (Advantage 20EC) acts
as the most effective insecticide for the control of aphids on Wheat. The
present study was to check the severity of effects of various concentrations of
carbosulfan (advantage 20EC) on R. padi in terms of the fecundity rate, survival rate,
adult longevity and age specific maternity.
My results of bioassay in laboratory showed
significant differences in mortality and fecundity of R. padi
feeding on the plants. Total pre adult period and the
preadult survival showed maximum increase at 1.4×10-13
ppm. The female longevity and the total longevity
increased the most at 1.4×10-13 ppm. The
nymph instars exposed to 1.4×10-7 ppm and
1.4×10-10 ppm showed lower values of TPRP
and APRP. At lowers concentration (1.4×10-13 ppm)
net reproductive rate (R0) is more as compared to other two
concentrations. Effect on biology with respect to fecundity (5.36±0.56) was
recorded highest in exposure to concentration (1.4×10-10 ppm) at it decreased the most at that concentration. In
life table parameters measurement, it was noted that intrinsic rate of increase
and finite rate of increase were highest at 3rd concentration (1.4×10-13
ppm) in the larval life span. The mean generation
time (T) and the net reproductive rate (R0) also
increased at 1.4×10-13 ppm. Torres and Ruberson (2004) support my results that, all nymph instars
(N1, N2, N3, N4) are affected more at higher concentration and their survival
rate is more at lower. All three concentrations used in experiment had
significant impact on aphid population when compared with control plot. Maximum
population reduction was observed in T2 with application of Advantage 20 EC @
300 ml/acre and proved to be more effective insecticide against the canola
aphid, L. erysimi Kalt.
as compared to other insecticides succeeded by T1 with
Actara 25 WP @ 24 g/acre, T3 with Confidor
200 SL @ 150 ml/acre and T4 with Mospilan 20 SP @ 80
g/acre (Ahmad et al., 2017). Sublethal
concentrations of insecticides like carbofuran and bifenthrin are shown to have negative effects on aphid’s
population growth and biology as the concentrations increase (Kerns and Stewart
2000). Calafiori et
al. (1999) reported that carbosulfan @0.6 L ha-1 provided
more than 80% control of aphids and thrip in cotton. Chinnaiah and Asif (1999)
reported that carbosulfan @25 g a.i
kg-1 seed reduced the number of sucking pests of cotton such as
leafhoppers and aphids after sowing up to 45 days. Moreover, R. padi was more susceptible to all insecticides than S.
avenae and S. graminum
and all the insecticides were more effective against R. padi than S. avenae and
S. graminum. However, malathion, bifenthrin, imidacloprid, pymetrozine, carbosulfan and thiamethoxam significantly
decreased the population of R. padi (Faheem et al.,
2016). When R. padi aphids fed on
leaves of wheat treated with sublethal concentrations
of insecticides, their xylem feeding was reduced. Moreover, the feeding on sublethal concentrations also reduced their body water
contents and at reproductive maturity the aphids were small,
light in weight and has less fecundity. The honeydew secretion was also
affected negatively (Daniels et al., 2009). Amer and his colleagues tested toxicity of different
conventional and neonicotinoide insecticides such as bifenthrin, carbosulfan, methamidophos, thiamethoxam and imidacloprid on aphids and there was a clear difference in
effected aphids and control plots (Amer et al., 2010). When generations
of R. padi were exposed to sublethal
doses of insecticides it was noted that their, both fecundity and longevity
were significantly decreased after exposure (Lu et al., 2016). This study
will be helpful to understand how Carbosulfan changes
the biology of aphids at low concentrations and the susceptibility of nymphs of
aphids to lower concentrations of insecticide.
Conflict of interest
The author declared that they have no conflicts
of interest to this interest. The authors declare that they do not have any
associative or commercial interest that represents a conflict of interest in
connection with the work submitted.
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