Abstract
The present study aimed to evaluate the toxic and biological effects of some extracts of seagrasses (Cymodocea rotundata; Halophila ovata& Thalassia hemprichii) against Aedes aegypti, which transmits dengue fever, and Culex pipiens, which is the dominant species of mosquitoes in the Kingdom of Saudi Arabia, as a safe method for its control. The cumulative death rate during larval development into pupae and adults was used as a criterion for evaluating tested seaweed extracts against Ae. aegypti, Cx. Pipiens. According to the obtained IC50 values (the concentration that inhibits the exit of 50 % of adult mosquitoes), the results showed that C. rotundata extract (70.78 & 77.47 ppm) was more effective against A. aegypti and Cx. pipiens in comparison with H. ovata (86,98 & 95,87 ppm) and T. hemprichii (83,94 & 88,82) extracts by (1.186, 1.229, 1.146 & 1.237) fold, respectively. The results showed that the treatment with marine plant extracts against mosquito larvae of Cx. Pipiens and Ae. Aegypti gave different biological effects similar to those of other insect growth regulators (IGRs). The results also revealed the presence of morphological abnormalities in larvae that were treated with all seaweed extracts and these effects extended to all stages of growth, which caused damage to the insect without completing its life cycle. Generally, the results indicate the importance of carrying out bio-assessment tests for the pesticides that are used against mosquitoes and establishing a database to be referenced when planning control programs and making the right decision about the pesticide used.
Keywords: Aedes aegypti, Culex pipiens, Control, Cymodocea rotundata, Halophila ovata, Thalassia hemprichii
1. Introduction
Worldwide, the mosquito is still relevant to the most important epidemic diseases, where the diseases they transmit pose a fatal threat to millions of people around the world Govindarajan et al. (2016). Mosquito Females transmit a lot of diseases to humans, such as; Malaria which is caused by the transmission of the Plasmodium parasite, it is one of the most dangerous pathogens transmitted by female mosquitoes, with a child dying every 30 s globally and killing more than one million people annually. Also, they transmit the nematode worms that cause elephantiasis, which is a non-fatal disease but causes social hardship and disability. It comes in the second rank after leprosy as a cause of lifelong disability. In addition, they transmit the virus that causes dengue fever and which is considered one of the most important viral diseases transmitted by mosquitoes at the present time and the most widespread, the indicators confirm that this disease is growing steadily, both in terms of the number of cases of infection or the number of countries in which the disease is endemic (Govindarajan and Benelli, 2016).
Although the traditional chemical pesticides have been used in pest control for more than 100 years; however, the danger still exists, in addition, to the damage of pesticide residues in the food chains, especially since some of them are not easily degradable. Not to mention the many harmful effects of these pesticides on humans, pets, wildlife and the environment (Matsumura, 1985).
On the other hand, the indiscriminate and extensive use of traditional chemical pesticides led to the recording of resistance against many insecticides in 504 species of arthropods all over the world, including vectors of epidemic diseases, especially mosquitoes (Georghiou, 1991).
It recorded the phenomenon of resistance against all major types of insecticides, including organochlorine compounds and organophosphorus compounds; carbamates; and synthetic pyrethroids (Beach et al., 1989).
With the development of chemical analysis devices for pesticide residues, many environmental risks have emerged from the indiscriminate use of chemical pesticides, whether it is to control public health pests or agricultural pests. In addition to the emergence of resistance against many of them (Benelli, 2015).
To solve this problem, efforts have been directed towards the search for new and effective compounds that do not have harmful effects on the non-target population and organisms in the breeding sites and have a water basis that is easily degradable; the active substances extracted from plants are considered the best alternative source for mosquito control because they contain biologically active compounds that reduce mosquito reproduction (Sukumar et al., 1991, Wink, 1993).
A number of plant extracts have been reported to possess biological activities as larvicides against different types of mosquitoes (Goellner et al., 2018).
In the early part of history, humans used some plants and compounds extracted from them to control some insects that transmit diseases to humans and their domesticated animals. There is a tendency to search for these compounds on a large scale because the use of readily biodegradable plant compounds is one of the safest methods for controlling insect pests and disease vectors (Alkofahi et al., 1989).
Some studies also indicated the advantages of using medicinal plant extracts in mosquito control, being effective and significantly reducing the risks of harmful environmental effects from the use of chemical pesticides, in addition to the fact that mosquitoes did not acquire resistance against them. Recently, interest in research regarding the potential use of plant extracts as alternatives to synthetic insecticides has increased, with many researchers around the world beginning to test some medicinal and herbal plants for mosquito control (Choochote et al., 2004).
The current study aims to keep pace with recent trends in mosquito control by evaluating the biological activity; toxic and delayed effects of some marine grasses growing on the Saudi Red Sea coast against larvae of Ae. aegypti which is the main vector of dengue virus types and larvae of Cx. pipiens is prevalent species in Saudi Arabia.
2. Materials and methods
2.1. Definition of tested species
2.1.1. Eggs stage
Females of the species Culex pipiens lay eggs in boat-like clumps where the bottom side touching the water is convex and the upper side is concave and the eggs are perpendicular to the surface of the water, and they do not have the ability to withstand drought (Fig. 1A), While females of the species Ae. aegypti lay oval eggs, single, spindle-shaped and it is black color at the edges of the water or in wet places. These eggs are characterized by resistance to drought for several months (Fig. 1B).
Fig. 1.
The eggs (A) Cx. pipiens (B) Ae. Aegypti.
2.1.2. Larvae stage:
The larva is characterized by a long siphon with more than one tuft of hair branching from its root in the form of a ray in Cx. pipiens (Fig. 2A), while the siphon is short, barrel-shaped and contains a single hair tuft in Ae. aegypti (Fig. 2B).
Fig. 2.
The larva (A) Cx. pipiens (B) Ae. Aegypti.
2.1.3. Pupa stage
The pupae of mosquitoes are difficult to distinguish, nevertheless, pupae of the genus Culex are tubular and in Cx. pipiens respiratory horns are long (Fig. 3A), while in Ae. aegypti the respiratory horns are short as in (Fig. 3B).
Fig. 3.
The pupa (A) Cx. pipiens (B) Ae. Aegypti.
2.1.4. Adult stage
The adult insect of Cx. pipiens is light brown in color and the end of the abdomen is rounded and the scales of its are regular section (Fig. 4A), while in Ae. aegypti the insect is dark brown or blackish in color and the end of the abdomen is tapering with white scales distributed on the body, especially dorsally from the thorax with a lyre shape (Fig. 4B).
Fig. 4.
The adult (A) Cx. pipiens (B) Ae. Aegypti.
2.2. Laboratory breeding of tested mosquitoes
The eggs were obtained from the Dengue Research Unit of the Department of Biological Sciences at King Abdul-Aziz University. The breeding of mosquitoes was at a laboratory dedicated to breeding mosquito strains in the unit, where the egg blocks of Cx. pipiens were placed in porcelain dishes with white background of 30 × 20 depth 7 cm and filled to the middle with tap water. Whereas the species Ae. aegypti the filter papers must be placed in breeding dishes and immersed in water.
Mosquito larvae were fed food, which is a mixture of yeast and fish food flakes in a 1:1 ratio, with daily follow-up until the pupal stage. When the larvae turn into pupae, they are collected using a transparent plastic dropper to be placed in cups containing water and then inserted into square cages with dimensions of 30 × 30 × 30 cm designated for breeding mosquitoes to follow the exit of the adult insect.
After the adult emergence, males and females are fed on a 10 % sugar solution for three days. To obtain eggs, the females are starved by keeping the sugar solution away for 12–24 h, then females were fed on a blood meal using the Mosquito Membrane Feeder.
After two to three days of blood-feeding, the breeding cages are provided with dishes of water to receive the egg laid by the blood-fed females. After laying eggs, the previous steps are repeated in order to obtain a sufficient number of larvae to carry out all research experiments.
2.3. Bioassay experiments
The extracts were obtained and their insecticidal activity was measured against mosquito larvae in the Natural Products Laboratory of the Dengue Mosquito Research Unit and Vector Control, Department of Biological Sciences KAU.
2.3.1. Seagrasses tested
Three types of seagrasses (Cymodocea rotundata; Halophila ovata & Thalassia hemprichii) that grow in the Gulf of Salman area on the Saudi Red Sea coast were collected as shown in (Fig. 5).
Fig. 5.
Seagrasses tested.
2.3.2. Preparation of extracts
The three samples were washed well with water to get rid of sediments, algae and suspended dust, then the washing process was repeated using distilled water after that samples were dried at room temperature to keep the compounds from breaking down. The leaves of each sample were crushed separately with an electric grinder and placed inside a sealed plastic box until the start of extraction.
Cold extraction was carried out using a mixture of seagrasses powder and methanol alcohol in a ratio of 1:3 taking into account the shaking of the samples by Vortex Shakers (The solvent was removed for each extract separately using a Rotary Vacuum Evaporator at a temperature of 45 °C to obtain the crude extract of the sample completely dry according to the method (Mahyoub, 2021, Al-Hakimi et al., 2022a).
2.3.3. Preparation of stock solutions
Standard solutions of the tested extracts were prepared by taking 1 g of each extract and dissolving it in 98.5 ml distilled water in a 250-standard flask. 0.5 ml Triton X-100 was added as an emulsifier to ensure a homogeneous distribution of the extract with the extracts completely dissolved using the Ultrasound Sonicator.
2.3.4. Test trials
The tests were carried out in small white plastic dishes (11 cm diameter, 4 cm depth) containing 100 ml of water as a test environment. The larvae at the beginning of the fourth instar were exposed to a series of different concentrations of each extract. Five replicates were used for each concentration, where every replicate contained 20 larvae, in addition to five replicates for the control, taking into account the feeding of larvae during the treatment.
The number of dead larvae, as well as the dying larvae, were recorded on a daily basis, taking into account the transfer of live pupae to cups containing clean water to follow up on the late effects of these extracts and recording the number of dead pupae daily and calculating the number of insects that succeed in reaching the adult stage for each replicate separately. Dead larvae and pupae were maintained in 70 % ethyl alcohol to study them under an anatomical microscope to determine the morphological abnormalities in different instars as physiological effects of these extracts.
Where these extracts cause a physiological imbalance during the stages of the development of the insect, similar to the effect of growth hormone, which can lead to the appearance of abnormal molts since these distortions have been taken into account when evaluating this type of compounds. The evaluation was also done on the basis of recording the percentage emergence of adults for each concentration and calculating the average percentage of inhibition in the exit of adults resulting from larvae treated for each concentration separately, given that the extracts were from compounds with delayed effects, the evaluation was done on the basis of calculating the percentage of cumulative mortality of larvae, pupae and adults.
2.4. Statistical analysis
Abbott's equation was used to correct the percentage of death in the treatments, according to its counterparts in the control, in the experiments in which the death rate at the control exceeded 5 %, and it was less than 20 % Abbott (1925). The results were analyzed using a specialized statistical program IC-p lines. Toxicity curves were drawn that show the relationship between the concentrations used and the percentage of inhibition of the exit of adults resulting from larval treatments by tested extracts and recording all Statistical parameters such as Chi -squared values; LC50; IC50 values; Fiducial limits; Slope and other statistical constants that help to interpret the results and compare between the tested compounds, according to the method of (Litchfield & Wilcoxon 1949).
3. The results
The sensitivity level of the fourth-instar larvae of Ae. aegypti and Cx. pipiens were measured for some marine grasses extracts (H. ovata, T. hemprichii, C. rotundata.) that grow on the Saudi Red Sea coast. The insecticidal annihilation effect of selected extracts against mosquito larvae was evaluated, whereas the death rates of larvae were recorded, with daily follow-up of experiments until they became pupae, as well as until the exit of the adults.
With the registration of the cumulative mortality ratios in larvae, pupae and adults of insects, as well as the calculation of the percentages of inhibition of the exit of adults and adults of larvae treated with different concentrations of extracts. The IC indicator was used because these compounds are not toxic or have rapid effects, as is the case with conventional chemical pesticides, but are compounds that act with delayed action as an inhibitor of chitin synthesis in insects or a similar effect of Juvenile hormone.
The results in Table 1 showed the effective concentrations of C. rotundata ranged from 50 − 130 ppm, the death rates of the fourth-instar mosquito larvae of Ae. aegypti and Cx. pipiens were in the range of (20–74) % and (16–70) %, respectively. Percent inhibition of exit of adult insects varied from (27–92) for Ae. aegypti and from (22–87) % for Cx. pipiens at the concentrations tested ranging from (50–130) ppm, with a mean death recorded in the control treatment of 2 %.
Table 1.
The biological effects of the Seagrasses extracts C. rotundata, T. hemprichii and H. ovata on the developmental stages of Ae. aegypti and Cx. pipiens.
| Seagrasses extracts | Mosquito Species | Effective Concentrations (ppm) |
Larval mortality * (%) |
Pupation (%) |
Adultemergence (%) |
Adult emergence Inhibition (%) |
|---|---|---|---|---|---|---|
| C. rotundata | Ae. aegypti | 50–130 | 20–74 | 80–26 | 73–8 | 27–92 |
| Cx. pipiens | 50–130 | 16–70 | 84–30 | 78–13 | 22–87 | |
| T. hemprichii | Ae. aegypti | 50–170 | 10–80 | 90–20 | 78–7 | 22–93 |
| Cx. pipiens | 50–170 | 6–76 | 94–24 | 83–12 | 17–88 | |
| H. ovata | Ae. aegypti | 50–170 | 18–88 | 82–12 | 78–3 | 22–97 |
| Cx. pipiens | 50–170 | 14–84 | 86–16 | 83–8 | 17–92 |
* Five replicates were used, with 20 larvae/repeat; control adult emergence Inhibition ranged from 0.0 − 2%.
The values of IC50 and IC90 were (70.78 & 128.4) ppm for Ae. aegypti and (77.47 & 141.5) ppm for Cx. pipiens. The (RR) values showed that C. rotundata extract was more effective against Ae. aegypti by 1.09 times than its effect on Cx. pipiens as shown in Table 2 and Fig. 6.
Table 2.
The values of inhibitory concentrations for the emergence of 50 & 90% of adult insects resulting from the treatment of fourth instar larvae and the different stages of Ae. aegypti and the Cx. pipiens by the extract of C. rotundata.
| Statical parameters | Mosquito Species |
Resistance Ratio (R.R) |
|
|---|---|---|---|
| Ae. aegypti | Cx. pipiens | ||
| IC50(ppm) 95 % (F. L.) |
70.78 66.09–75.10 |
77.47 72.77–82.03 |
1.095 |
| IC90 (ppm) 95 % (F. L.) |
128.4 117.6–144.4 |
141.5 128.7–161.2 |
|
| Slope | 4.9533 | 4.8954 | |
| Tabulated (Chi)2 | 7.81 | 7.81 | |
| calculate (Chi)2 | 3.4305 | 2.0527 | |
(Chi)2 Tabulated is larger than calculated, at a 0.05 level of significance which indicates the homogeneity of results.
Five replicates, 20 larvae for each.
The mortality rate in the control ranged from% (2–0).
Fig. 6.
The relationship between the tested concentrations of C. rotundata extract and the percentage of adult emergence inhibition resulting from the treatment of the fourth instar larvae of Ae. aegypti & Cx. Pipiens.
The effective concentrations of T. hemprichii extract ranged between (50–170) ppm, while the percent inhibition of adult insect emergence resulting from the treated larvae ranged between (22–93 %) for Ae. aegypti and (17–88) % for Cx. pipiens Table 1.
The IC50 and IC90 values were (86.98 and 178.9) ppm for Ae. aegypti and (95,86 and 198.08) ppm from Cx. pipiens, respectively. According to the resistance ratio values obtained, the fourth instar larvae of Cx. pipiens were more tolerant to the extract concentrations of T. hemprichii than those of Ae. aegypti by 1,102 times as shown in Table 3 and Fig. 7.
Table 3.
The values of inhibitory concentrations for the emergence of 50 & 90% of adult insects resulting from the treatment of fourth instar larvae and the different stages of Ae. aegypti and the Cx. pipiens by the extract of T. hemprichii.
| Statical parameters | Mosquito Species |
Resistance Ratio (R.R) |
|
|---|---|---|---|
| Ae. aegypti | Cx. pipiens | ||
| IC50(ppm) 95 % (F. L.) |
86.98 80.46–93.29 |
95.87 89.10–102.6 |
1.102 |
| IC90 (ppm) 95 % (F. L.) |
178.9 160.5– 206.8 |
198.08 198.08–232.05 |
|
| Slope | 4.0903 | 4.0661 | |
| Tabulated (Chi)2 | 7.81 | 7.81 | |
| calculated (Chi)2 | 5.3592 | 2.6408 | |
(Chi)2 Tabulated is larger than calculated, at a 0.05 level of significance which indicates the homogeneity of results.
Five replicates, 20 larvae for each.
The mortality rate in the control 1%.
Fig. 7.
The relationship between the tested concentrations of T. hemprichii extract and the percentage of adult emergence inhibition resulting from the treatment of the fourth instar larvae of Ae. aegypti & Cx. pipiens.
The level of sensitivity of fourth-instar larvae for Ae. aegypti and Cx. Pipiens to the H. ovata extract were evaluated, with the results as shown in Table 1 and Fig. 8 showing that the percentages of larval death ranged from (18–88) and (14–84) % when treated at concentrations between (50–170) ppm for both species. While the percent inhibition of emergence of adults resulting from larvae that were treated with H. ovata extract varied from (22–97) % for Ae. aegypti and (17–92) % for Cx. pipiens at the same concentrations.
Fig. 8.
The relationship between the tested concentrations of H. ovata extract and the percentage of adult emergence inhibition resulting from the treatment of the fourth instar larvae of Ae. aegypti & Cx. pipiens.
The IC50 and IC90 values were between (83.9 & 162.8) ppm for Ae. aegypti and (88.8 & 165.5) ppm for Cx. pipiens respectively. The results also indicate that fourth-instar larvae of Cx. pipiens were more tolerant when treated with H. ovata extract compared to Ae. aegypti with a value of 1,058 times, corresponding to the resistance ratio values in the Table 4.
Table 4.
The values of inhibitory concentrations for the emergence of 50 & 90% of adult insects resulting from the treatment of fourth instar larvae and the different stages of Ae. aegypti and the Cx. pipiens by the extract of H. ovata.
| Statical parameters | Mosquito Species |
Resistance Ratio (R.R) |
|
|---|---|---|---|
| Ae. aegypti | Cx. pipiens | ||
| IC50(ppm) 95 % (F. L.) |
83.94 77.76–0.117 |
88.82 82.98–94.52 |
1.058 |
| IC90 (ppm) 95 % (F. L.) |
162.83 147.1–186.2 |
165.52 151.1–186.1 |
|
| Slope | 4.4534 | 4.741 | |
| Tabulated (Chi)2 | 7.81 | 7.81 | |
| calculated (Chi)2 | 6.8805 | 3.9269 | |
(Chi)2 Tabulated is larger than calculated, at a 0.05 level of significance which indicates the homogeneity of results.
Five replicates, 20 larvae for each.
The mortality rate in the control 0.0%.
The results of this study show that there are differences in the sensitivity level of mosquito larvae to the tested extracts. Ae. aegypti is more susceptible to C. rotundata extract compared to H. ovata and T. hemprichii extracts by (1,186 & 1,229) fold, respectively, Table 5 and Fig. 9, while Cx. pipiens larvae were approximately (1,14&1.23) times more susceptible to the C. rotundata extract compared to the H. ovata and T. hemprichii extracts respectively, as shown in Table 6 and Fig. 10.
Table 5.
Comparison of the sensitivity level of fourth instar larvae of Ae. aegypti for tested seagrasses H. ovata, T. hemprichii, C. rotundata.
| No | Line name | IC50 (ppm) | RR |
|---|---|---|---|
| 1 | Cymodocea rotundata | 70.78 | 1 |
| 2 | Halophila ovata | 83.94 | 1.186 |
| 3 | Thalassia hemprichii | 86.98 | 1.229 |
Fig. 9.
IC-p lines that show the relationship between the concentrations of the tested extracts (C. rotundata, T. hemprichii & H. ovata) and the percentage of mortality of the fourth instar larvae of Ae. aegypti after continuous exposure to the extract for several days.
Table 6.
Comparison of the sensitivity level of fourth instar larvae of Cx. pipiens for tested seagrasses H. ovata, T. hemprichii, C. rotundata.
| No | Line name | IC50 (ppm) | RR |
|---|---|---|---|
| 1 | Cymodocea rotundata | 77.48 | 1 |
| 2 | Halophila ovata | 88.825 | 1.146 |
| 3 | Thalassia hemprichii | 95.865 | 1.237 |
Fig. 10.
IC-p lines that show the relationship between the concentrations of the tested extracts (C. rotundata, T. hemprichii & H. ovata) and the percentage of mortality of the fourth instar larvae of Cx. pipiens after continuous exposure to the extract for several days.
On the other hand, the results obtained confirmed that the sea-grasses extracts tested had biological effects against the different developmental stages of both Ae. aegypti- as well as Cx. pipiens species, and these abnormalities resembled those induced by insect growth regulators (IGR).
Through Fig. 11, Fig. 12, the results of this study demonstrated the failure of some mosquito larvae to moult to the pupal stage, where the extract-treated larvae gave intermediate stages combining characteristics of larva and pupa or between pupa and adult insect, in addition to the appearance of dwarfism and shrinkage of the body segment of the larvae, where all the intermediate stages die-off. The study also showed that some of the larvae, which appeared to have developed into a natural pupa, either died before reaching the adult stage or died as albino pupae immediately after moulting. In addition, some of the adults that emerged from the extract-treated larvae had wings that were folded out of the pupa or attached to the skin during moulting.
Fig. 11.
Morphological effects of the tested extracts against different stages of Cx.pipiens. A: (1) untreated larva; (2) Elongation in the neck; (3) Shrinking of the abdominal rings; (4) pigmentation B): (5) Untreated pupa; (6) An intermediate stage between adults and pupa; (7) An intermediate stage; (8) Failed to develop in to an adult insect C): (9) Untreated adult mosquitoes; (10–12) Failed to get the adult insect out of moulting skin.
Fig. 12.
Morphological effects of the tested extracts against different stages of Ae. aegypti A: (1) untreated larva; (2) Elongation in the neck; (3) Shrinking of the abdominal rings; (4) pigmentation B): (5) Untreated pupa; (6) An intermediate stage between adults and pupa; (7) Albino pupa; (8) Failed to develop into an adult insect C): (9) Untreated adult mosquitoes; (10–12) Failed to get the adult insect out of moulting skin.
4. Discussion
There is no doubt that the random and wasteful use of chemically manufactured pesticides has caused serious damage to the environment and to human and animal public health, that often outweighs the desired benefits of their use, in addition to the fact that many species of mosquitoes have it acquired resistance to many of them; therefore, the need arose to look for safer alternatives that would help control mosquitoes and reduce their harm. Using plant-based insecticides is one of the safest ways to overcome the problems associated with using synthetic compounds in mosquito control. In this study, the results showed that sea-grasses extracts tested under laboratory conditions were effective against two species of mosquitoes; Ae. aegypti which causes dengue fever and Cx. pipiens, which is prevalent species in Saudi Arabia.
The results showed late efficacy of the sea-grasses extract in the pupation process and exit of adults, therefore IC50 was used as a standard to assess the effectiveness of the extracts tested against selected mosquito species, and results of this study are consistent with many studies on the effect of plant extracts on various species of mosquito (Elimam and Ombabi, 2007, Elimam et al., 2009, Zahran and Abdelgaleil, 2011).
The results also showed that the sensitivity of the mosquito larvae and the resulting stages of the larvae treated with the tested sea-grasses extracts vary, which may be due to the levels of active substances contained in these plants, therefore differ in their effect, or maybe because to the active substances contained in the tested- extracts, which need to be separated and isolated in subsequent studies to determine their chemical composition and mode of action (Ghosh et al., 2012, Al-Hakimi et al., 2022b).
By analyzing the results, it was observed that there was a positive relationship between the concentrations tested and larval mortality rates, as well as the percentage of inhibition of adult insect emergence. The reason for this may lie in the increased binding of active ingredients to sensitive sites in the insect’s body with increasing concentration, and possibly the reason lies in a decrease in the enzymes that decompose toxic substances released, which are released by insects as a defense method for species preservation, at the low concentration) Mansour et al., 2010).
On the other hand, Cx. pipiens larvae are more tolerant to the tested marine extracts and this may be due to cross-resistance, as marine extracts have a mode of action quite similar to the group of insect growth regulators, that is the most common and used to control mosquito larvae in swamps, which are suitable environments for this species of mosquito, unlike the Ae. aegypti that prefers shaded water and indoors.
It is worth noting that there are many indicators confirming the breadth of mosquito resistance to all commonly used organophosphorus groups and pyrethroid compounds, as well as many evidence of emerging resistance against some of the IGRs according to (WHO, 1990).
Overall, the current study was consistent with many scientific researches conducted in most countries around the world, to confirm the effectiveness of many plants and sea-grasses extracts against different species of mosquitoes. These scientific studies showed the importance of using plant extracts as alternative methods in the field of mosquito control, which transmits many pathogens, to reducing the problems of traditional chemical pesticides causing the death of natural enemies, which alters the biotic balance in the environment. In addition to the emergence of a resistance mosquito strains to these pesticides. (Mahyoub et al., 2016a, Mahyoub et al., 2016b, Mahyoub, 2016c, Murugan et al., 2017, Barnawi et al., 2019, Mahyoub, 2021).
The results of this study showed that treatment of fourth-instar larvae of Cx. pipiens and Ae.aegypti with marine extracts resulted in intermediate instars having larval and pupa characteristics or between pupa and adult insect characteristics and some larvae evolved into albino pupae. In addition to that, some of the adult insects that evolved from the extract-treated larvae were related to the moulting skin of the pupae, and these results are consistent with much previous research (Bridges et al., 1977, Saleh and Aly, 1987, Al-Sharook et al., 1991).
The action of these extracts in all growth stages may be due to the fact that they contain compounds whose effect on mosquito larvae is similar to that of the mode of action of insect growth regulators, such that these compounds interfere with the physiological processes of the insect during its metamorphosis, or there may be an imbalance between stimulating or inhibiting the secretion of Eecdysone hormone or Juvenile hormone. or due to that these compounds can disrupt the work of hormones secreted by the endocrine glands, which leads to a defect in the growth process and death of the insect. These abnormalities arising from this study are similar to those resulting from the effect of growth regulators on mosquito larvae observed by many researchers (Silva and Mendes, 2007, Arivoli and Tennyson, 2011).
From the above, it can be said that conducting bioassay experiments against the prevalent mosquitoes in an area will provide baseline data on their level of sensitivity to compounds used in that area and will understand the nature of mosquito resistance to them. This is undoubted of paramount importance when planning mosquito control programs and making the right decisions about the best use of pesticides (Paeporn et al., 2005).
Declaration of Competing Interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Footnotes
Peer review under responsibility of King Saud University.
Contributor Information
Hayat S. Al-Rashidi, Email: Halrashidi0014@stu.kas.edu.sa.
Jazem A. Mahyoub, Email: jabdulrahman@kau.edu.sa.
Khalid M. Alghamdi, Email: Kalghamdy@kau.edu.sa.
Wafa Mohammed Al-Otaibi, Email: w.alotaibi@tu.edu.sa.
References
- Abbott W.S. A method of computing the effectiveness of an insecticide. J. Econ. Entomol. 1925;18(2):265–267. [Google Scholar]
- Al-Hakimi A.N., Alhag S.K., Abdulghani M.A., Aroua L.M., Mahyoub J.A. Evaluation of synthesized inorganic nanomaterials Plumeria alba against Aedes aegypti and in vivo toxicity. Main Group Chem. 2022:1–14. [Google Scholar]
- Al-Hakimi A.N., Abdulghani M.A., Alhag S.K., Aroua L.M., Mahyoub J.A. Larvicidal activity of leaf extract of Nerium oleander L. and its synthesized metallic nanomaterials on dengue vector, Aedes aegypti. Entomol. Res. 2022;52(3):148–158. [Google Scholar]
- Alkofahi A., Rupprecht J.K., Anderson J.E., Mclaughlin J.L., Mikolajczak K.L., Scott B.A. Search for new pesticides from higher plants. Insect. Plant Origin. 1989;387:25–43. [Google Scholar]
- Al-Sharook Z., Balan K., Jiang Y., Rembold H. Insect growth inhibitors from two tropical Meliaceae: Effect of crude seed extracts on mosquito larvae 1. J. Appl. Entomol. 1991;111(1–5):425–430. [Google Scholar]
- Arivoli S., Tennyson S. Larvicidal and adult emergence inhibition activity of Abutilon indicum (Linn.)(Malvaceae) leaf extracts against vector mosquitoes (Diptera: Culicidae) J. Biopesticid. 2011;4(1):27–35. [Google Scholar]
- Barnawi A.A.B., Sharawi S.E., Mahyoub J.A., Al-Ghamdi K.M. Larvicidal studies of Avicennia marina extracts against the dengue fever mosquito Aedes aegypti (Culicidae: Diptera) Int. J. Mosquito Res. 2019;6:55–60. [Google Scholar]
- Beach R.F., Cordon-Rosales C., Brogdon W.G. Detoxifying esterases may limit the use of pyrethroids for malaria vector control in the Americas. Parasitol. Today (Personal ed.) 1989;5(10):326–327. doi: 10.1016/0169-4758(89)90126-9. [DOI] [PubMed] [Google Scholar]
- Benelli G. Plant-borne ovicides in the fight against mosquito vectors of medical and veterinary importance: a systematic review. Parasitol. Res. 2015;114(9):3201–3212. doi: 10.1007/s00436-015-4656-z. [DOI] [PubMed] [Google Scholar]
- Bridges A.C., Cocke J., Olson J.K., Mayer R.T. Effects of a new fluorescent insect growth regulator on the larval instars of Aedes aegypti. Mosquito News. 1977;37(2):227–233. [Google Scholar]
- Choochote W., Tuetun B., Kanjanapothi D., Rattanachanpichai E., Chaithong U., Chaiwong P., Pitasawat B. Potential of crude seed extract of celery, Apium graveolens L., against the mosquito Aedes aegypti (L.)(Diptera: Culicidae) J. Vector Ecol. 2004;29(2):340–346. [PubMed] [Google Scholar]
- Elimam A.M., Elmalik K.H., Ali F.S. Larvicidal, adult emergence inhibition and oviposition deterrent effects of foliage extract from Ricinus communis L. against Anopheles arabiensis and Culex quinquefasciatus in Sudan. Trop. Biomed. 2009;26(2):130–139. [PubMed] [Google Scholar]
- Elimam M.E., Ombabi Y.A. Carcass characteristics of male Desert goats in Elobeid area in North Kordofan State, Sudan. Gezira J. Agri. Sci. 2007;5(2) [Google Scholar]
- Georghiou G.P. CTD/OPR/EC/91. Expert Committee on Insecticide Resistance Geneva. 1991. New developments in biochemistry and genetics of vector resistance to pesticides and their relevance to solving control problem. [Google Scholar]
- Ghosh A., Chowdhury N., Chandra G. Plant extracts as potential mosquito larvicides. Indian J. Med. Res. 2012;135(5):581. [PMC free article] [PubMed] [Google Scholar]
- Goellner E., Schmitt A.T., Couto J.L., Müller N.D., Pilz-Junior H.L., Schrekker H.S., da Silva O.S. Larvicidal and residual activity of imidazolium salts against Aedes aegypti (Diptera: Culicidae) Pest Manag. Sci. 2018;74(4):1013–1019. doi: 10.1002/ps.4803. [DOI] [PubMed] [Google Scholar]
- Govindarajan M., Benelli G. α-Humulene and β-elemene from Syzygium zeylanicum (Myrtaceae) essential oil: highly effective and eco-friendly larvicides against Anopheles subpictus, Aedes albopictus, and Culex tritaeniorhynchus (Diptera: Culicidae) Parasitol. Res. 2016;115(7):2771–2778. doi: 10.1007/s00436-016-5025-2. [DOI] [PubMed] [Google Scholar]
- Govindarajan M., Rajeswary M., Hoti S.L., Benelli G. Larvicidal potential of carvacrol and terpinen-4-ol from the essential oil of Origanum vulgare (Lamiaceae) against Anopheles stephensi, Anopheles subpictus, Culex quinquefasciatus and Culex tritaeniorhynchus (Diptera: Culicidae) Res. Vet. Sci. 2016;104:77–82. doi: 10.1016/j.rvsc.2015.11.011. [DOI] [PubMed] [Google Scholar]
- Litchfield J.T., Wilcoxon E. A simplified method of evaluating dose-effect experiments. J. Phar. Exp. Ther. 1949;96:99–113. [PubMed] [Google Scholar]
- Mahyoub J.A. Bioactivity of two marine algae extracts and their synthesized silver nanoparticles as safe controls against Musca domestica housefly. Entomol. Res. 2021;51(7):323–330. [Google Scholar]
- Mahyoub J.A., Alaa S.A., Khalid A.-G., Najat A.K., Al Thabiani A., Salman A.A., Chellasamy P., Kadarkarai M., Marcello N., Angelo C., Giovanni B. Effectiveness of seven mosquito larvicides against the West Nile vector Culex pipiens (L.) in Saudi Arabia Asian. Pac. J. Trop. Biomed. 2016;6(5):390–395. [Google Scholar]
- Mahyoub J.A., Al Thabiani A., Chellasamy P., Kadarkarai M., Mathath R., Subrata T., Marcello N., Usama W.H., Fekri M.S., Muneer A.B., Angelo C., Giovanni B. Seagrasses as Sources of Mosquito Nano- Larvicides? Toxicity and Uptake of Halodule uninervis-Biofabricated Silver Nanoparticles in Dengue and Zika Virus Vector Aedes aegypti. J. Clust. Sci. 2016 doi: 10.1007/s10876-016-1127-3. [DOI] [Google Scholar]
- Mahyoub J.A., Hawas U.W., Al-Ghamdi K.M., Aljameeli M.M.E., Shaher F.M., Bamakhrama M.A., Alkenani N.A. The Biological Effects of Some Marine Extracts Against Aedes aegypti (L.) Mosquito Vector of the Dengue Fever in Jeddah Governorate, Saudi Arabia. J. Pure Appl. Microbiol. 2016;10(3) [Google Scholar]
- Mansour S.A., Baker R.F.A., Hamouda L.S., Mohamed R.I. Toxic and synergistic properties of several botanical extracts against larval and adult stages of the mosquito Anopheles pharoensis. J. Biopesticid. Int. 2010;6(2):129–145. [Google Scholar]
- Matsumura F. Plenum Press; New York, U.S.A: 1985. Toxicology of Insecticides. [Google Scholar]
- Murugan K., Roni M., Panneerselvam C., Aziz A.T., Suresh U., Rajaganesh R., Mahyoub J.A., Benelli G. Sargassum wightii-synthesized ZnO nanoparticles reduce the fitness and reproduction of the malaria vector Anopheles stephensi and cotton bollworm Helicoverpa armigera. Physiol. Mol. Plant Pathol. 2017 doi: 10.1016/j.pmpp.2017.02.004. [DOI] [Google Scholar]
- Paeporn P., Kasin S., Sathantriphop S., Sangkitporn S. Department of Medical Sciences, Ministry of Public Health, National Institute of Health; Nonthaburi: 2005. Insecticides Susceptibility of Aedes aegypti in Tsunami-affected Areas in Thailand. [Google Scholar]
- Saleh M.S., Aly M.I. The biological effects of three insect growth regulators on Culex pipiens L. Anzeiger für Schädlingskunde. Pflanzenschutz, Umweltschutz. 1987;60(2):34–37. [Google Scholar]
- Silva J.J.D., Mendes J. Susceptibility of Aedes aegypti (L) to the insect growth regulators diflubenzuron and methoprene in Uberlândia, State of Minas Gerais. Rev. Soc. Bras. Med. Trop. 2007;40:612–616. doi: 10.1590/s0037-86822007000600002. [DOI] [PubMed] [Google Scholar]
- Sukumar K., Perich M.J., Boobar L.R. Botanical derivatives in mosquito control: a review. J. Am. Mosq. Control Assoc. 1991;7(2):210–237. [PubMed] [Google Scholar]
- World Health Organization (WHO), 1990. Handbook of environmental measures for mosquito control with special focus on malaria vectors. Regional Office for the Eastern Mediterranean, Alexandria, Egypt, pp. 297.
- Wink M. The plant vacuole: a multifunctional compartment. J. Exp. Bot. 1993:231–246. [Google Scholar]
- Zahran H.E.D.M., Abdelgaleil S.A. Insecticidal and developmental inhibitory properties of monoterpenes on Culex pipiens L. (Diptera: Culicidae) J. Asia-Pac. Entomol. 2011;14(1):46–51. [Google Scholar]