Insecticidal activity and phytochemical analysis of Pyrus communis L. extracts against malarial vector, Anopheles pharoensis Theobald, 1901 (Diptera: Culicidae)

We aimed at investigating the insecticidal activity of Pyrus communis L. against the malarial vector, Anopheles pharoensis Theobald, 1901 and its phytochemical constituents. Leaves were collected and the crude extracts were prepared using hexane (PCH) and methanol (PCM). Tested PCH and PCM possess larvicidal activity against A. pharoensis with LC50 and LC90 values of 179.9, 41.2 and 314.1, 68.9 ppm, respectively. A significant reduction in the number of eggs laid by females A. pharoensis that developed from larvae treated with PCH and PCM was noticed. Also, PCH treatment showed highest repellent activity compared with PCM. GC/MS analysis of the PCH revealed the presence of 55 identified compounds subdivided into 2 major classes viz. phenyl alkanes (38.65 %) and oxygenated sesquiterpenoids (36.41 %). LC/MS of PCM had led to the identification of 37 compounds, mainly flavonoids, chalcones, phenolic acids and tannins. The results demonstrate the insecticidal potential of leaves methanol and hexane extracts from P. communis as green insecticidal agents for the control of malarial vector, A. pharoensis.

Lethal and sublethal effects of bifenazate on the biological parameters of Tetranychus truncatus Ehara (Acari: Tetranychidae)

Tetranychus truncatus Ehara (Acari: Tetranychidae) is one of the serious pests that infests different agricultural crops in field and greenhouse crops, and its distribution is limited to mostly Asian countries. The experiments were conducted to know the effectiveness of different concentrations of bifenazate against the T. truncatus, and to evaluate and compare the demographic parameters of T. truncatus on host plant Lablab purpureus (L.) Sweet (Fabaceae), which were obtained from females treated with bifenazate. The LC15, LC30, LC50 and LC90 values are determined through the bioassay from the results of the first application of bifenazate on adult females of T. truncatus. The LC15, LC30, LC50 and LC90 concentrations of bifenazate were 0.417, 1.028, 2.591 and 24.792 ml/l, respectively. The response of adult females against the two lethal concentrations (LC15 and LC30) was mostly alike but had a little bit difference. The differences in life table parameters were observed between control and treated spider mites. The results demonstrated that LC15 and LC30 of bifenazate could reduce the survival rate, oviposition period, fecundity and longevity of females of T. truncatus and it significantly affected the developmental times, especially larval duration and fecundity of T. truncatus. Life-table parameters of T. truncatus were much reduced in LC15 and LC30 compared to the control and their growth and other factors showed significant differences. The present study showed that the lower lethal concentration (LC15 and LC30) of the tested acaricide showed negative effects on survivorship and life-table parameters of the subsequent generation of T. truncatus.

The effect of some insecticides on the larvae of Aedes aegypti in Jeddah Governorate, Makah Province, Kingdom Saudi Arabia

Mosquitoes can act as vectors for many disease-causing viruses and parasites through carrying these organisms from person to person. The objective of this study was to evaluate the susceptibility of Aedes aegypti larvae to some insecticides in Jeddah Governorate. Mosquito larvae were collected from all the available breeding sites in Jeddah municipalities using standard larval collection kits. The diagnostic doses (LC50 and LC90) were calculated from the mortality and concentration data. The larvicides Pirimiphos methyl, Fenitrothion, Bifenthrin and Cypermethrin were tested against the larvae of Ae. aegypti mosquito. The results showed positive correlation between the concentrations under investigation and mortality% of the treated larvae. Cypermethrin gave strong effect against Ae. aegypti larvae (LD50 0.0015 ml/L) followed by Pirimiphos methyl (LD50 0.0020 ml/L), Bifenthrin (LD50 0.039 ml/L), and at last rank Fenitrothion (0.041 ml/L). The same trend was obtained in LD90s. Ae. aegypti in Jeddah was susceptible to Bifenthrin, Cypermethrin, Pirimiphos methyl and Fenitrothion. Further studies should be run to conduct an intensive and appropriate vector control program in Jeddah Governorate.

Insecticidal efficacy of Rubus steudneri and Rubus apetalus against Aedes (Diptera: Culicidae) and Culex (Diptera: Culicidae) mosquitoes

Introduction and Aim: Rubus steudneri Schweinf. and Rubus apetalus Poir. belonging to the family Rosaceae is one of the ethnomedicinal plants used widely in Ethiopia as food, for construction and as medicine. To the best of our knowledge, insecticidal activity of R. steudneri and R. apetalus has not been investigated so far. In this study, we report insecticidal efficacy of R. steudneri and R. apetalus in terms of larvicidal effect against II and III instar larvae of Aedes and Culex mosquitoes. Materials and Methods: The shade-dried and powdered leaves were extracted using methanol by maceration process. Insecticidal activity of leaf extract was determined by larvicidal assay against II and III instar larvae of Aedes and Culex species. LC50 and LC90 values were calculated. Results: The leaf extract of both Rubus species exhibited concentration dependent larvicidal effect. II instar larvae were shown to be highly susceptible than III instar larvae. Among leaf extracts, extract of R. steudneri exhibited marked insecticidal activity when compared to extract of R. apetalus as revealed by lower LC50 and LC90 values. Culex larvae displayed marked susceptibility to leaf extracts when compared to Aedes larvae. Conclusion: Marked larvicidal effect was observed against larvae of Culex species when compared to Aedes species as indicated by lower LC50 and LC90 values. It is evident that the leaf extracts of both Rubus contain insecticidal principles.

Effectiveness of Ageratum conyzoides (Babandotan) Leaf Extract and Sapindus rarak (Lerak) Fruit Extract in Control of Myzus persicae in Chili Plants

Chili is one of the important agricultural commodities in Indonesia. Myzus persicae Sulz. is one of the important pests in Chili cultivation because it can cause damage up to 80%. Nabati insecticide utilization is one of the safer alternatives to control and more environmentally friendly than synthetic insecticides. One Nabati insecticide utilization that can be used in controlling pests are Ageratum conyzoides L extract and Sapindus rarak D.C extract . The purpose of this study was to determine the effectiveness of A. Conyzoides extract S. rarak extracts and extract S. rarak mixture of both in the control of M. persicae. This research was factorial, treatment consisted of 2 factors: 1 Nabati insecticide consists of A. Conyzoides and S. Rarak and factor of 2 each given concentration is 0 ml, 10 ml, 20 ml, 30 ml. Using a completely randomized design (CRD) with 16 treatments 3 replications. The results variance showed that the treatment performed with extracts from A. conyzoides effect on mortality, damage to crops, M. persicae life, and leaf greenness level after treatment. Extract treatment S. Rarak effect on mortality, M. persicae life and leaf greenness level after treatment. While treatment mix A. conyzoides leaf extracts and fruit extracts S. rarak effect on mortality, M. persicae life. The results showed that the treatment is effective in controlling pests aphids M. persicae are A. conyzoides leaf extract mixture of 30 ml and 30 ml S. rarak fruit extract with the highest mortality value of 96.14%, which gives a real influence in the control of aphids M. persicae and different real control. LC50 and LC90 showed the best application in the control extract are 18.46 ml and 51.86 ml.

Chemical Composition and Larvicidal Activity of Lavandula angustifolia Subsp. angustifolia and Lavandula dentata Spp. dentata Essential Oils against Culex pipiens Larvae, Vector of West Nile Virus

The Culex pipiens mosquito (Diptera: Culicidae) is highly suspected to be the vector responsible for the spread of several parasitic and viral diseases. The use of synthetic insecticides is generally the preferred method of controlling these mosquitoes’ proliferation. However, it has led to resistance problems in target mosquitoes and environmental damage. Hence, diverse plant extracts could be considered as an alternative and potential source as mosquito control agents. In this study, essential oils of Lavandula angustifolia subsp. angustifolia and Lavandula dentata spp. dentata that are growing in Morocco were examined for their insecticidal effects on Culex pipiens larvae. The bioassay was performed according to a methodology inspired by the standard protocol of the World Health Organization. The mortality rate was determined after 24 hours of exposure, and probit regression analysis was used to calculate LC50 and LC90. The chemical analysis revealed that the principal compounds of L. angustifolia subsp. essential oils include linalool, linalyl acetate, geraniol, lavandulyl acetate, camphor, β-caryophyllene, terpinen-4-ol, β-myrcene, and 1,8-cineole, while the essential oil of L. dentata spp. was mainly composed of 1,8-cineole, camphor, α-pinene, trans-pinocarveol, linalool, and borneol. These volatile compounds have shown a toxic effect against Culex pipiens larvae, with lethal concentrations LC50 and LC90 being, respectively, 140 µg/ml and 450 µg/ml, for the L. angustifolia subsp. essential oil. Meanwhile, they were estimated at 2670 µg/ml and 7400 µg/ml, respectively, for the L. dentata spp. essential oil. These results suggest using essential oils of two species of Lavandula to control the Culex pipiens mosquito. It could be useful for the study of new natural larvicidal compounds.

EVALUATION OF A NEW TRUCK-MOUNTED ULV SPRAYING MACHINE WITH BACILLUS THURINGIENSIS VAR. ISRAELENSIS AGAINST LARVAL CULEX QUINQUEFASCIATUS

A field study about the effectiveness of a new truck-mounted ultra-low-volume (ULV) machine against larval Culex quinquefasciatus Say was conducted at Anastasia Mosquito Control District of St. Johns County, St. Augustine, FL, during the summer of 2017. Cx. quinquefasciatus larvae were treated using a ground application at different concentrations of Bti using a new truck-mounted ULV sprayer with a horizontal nozzle. Mortality of larvae was recorded after 24 h, and droplet sizes were measured. Overall, Bti sprayed by the new truck-mounted ULV spraying machine at a concentration of 2.625 mg/L resulted in the highest mortality of mosquito larvae. The results indicate that the Bti concentrations of 0.875 mg/L and 0.065 mg/L resulted in a significant difference in mean larval mortality between each distance from the spray line (P < 0.05), while the mortality by the other 3 concentrations (0.477 mg/L, 2.625 mg/L, and 5.25 mg/L) tested did not. The LC50 and LC90 of Bti against larvae were 0.261 mg/L (0.239~0.286) and 1.687 mg/L (1.481~1.922), respectively. The coverage (swath) of the spray by the new ULV machine showed that the Bti could be sprayed at least 33 meters away with a 20 meter width. Therefore, the new truck-mounted ULV spraying machine with liquid Bti could be used to treat a large area effectively and efficiently and as an additional tool for the control of mosquito larvae.

Phytochemical Screening and Larvicidal Evaluation of Phyto-synthesized Silver Nanoparticles using Palmyra Palm Sprout Extract

One of the objectives of nanotechnology is to synthesize effective nanoinsecticides in a bid to reduce the prevalence of the numerous diseases caused by mosquitoes. This synthesis is even more vital in cases where phytochemicals from plants extracts are used as reducing agents. In this study, phytochemical screening of aqueous sprout extract of Palmyra palm (Borassus aethiopum) was performed, in accordance with some established methods and the results confirmed the presence of alkaloids, flavonoids, saponins, coumarins, glycosides, tannins, phenols as well as quinines, however, sterols, steroids and terpenoids were not detected. Subsequently, the sprout extract was used as a reducing agent in the synthesis of silver nanoparticles (AgNPs). Characterization with Fourier transform infrared and Ultraviolet-visible spectrometry was then carried out to confirm the synthesis. In addition, the AgNPs were further analyzed for larvicidal potency against 1st, 2nd 3rd and 4th instars Culex quinquefasciatus mosquito larvae, at interval concentrations of 5, 10, 20, 25 and 50 ppm. The LC50 and LC90 values discovered to be 9.103 ppm and 134.463 ppm with a correlation of 0.815, as well as 10.316 ppm and 118.810 ppm with a correlation of 0.801, for the 1st and 2nd instars, respectively. Meanwhile, the 3rd and 4th instars had LC50 and LC90 values of 17.585 ppm and 179.052 ppm, respectively, with a correlation of 0.807. This study provides a basis for extracting and analyzing the reduction potential of the phytochemicals present in the sprout extract, as well as the application of AgNPs, in controlling mosquito larvae population.

Efektivitas Campuran Ekstrak Daun Srikaya (Annona squamosal L.) dan Rimpang Kunyit (Curcuma domestica Val.) pada Mortalitas Larva Spodoptera litura F. (Lepidoptera: Noctuidae)

Spodoptera litura F. larvae (Lepidoptera: Noctuidae) are polyphagous insects that cause damages to many types of plantations and horticulture that need to be protected. One of environmentally friendly method to protect ecological balance is the use of botanical insecticides whose bioactive compounds come from plant extracts. This study used a mixture of two plant extracts from A. squamosa leaves extract and C. domestica rhizome exstract (the mixed of experimental extracts). The mixed of experimental extracts are synergistic so that they are more effective and need a lower concentration to cause the mortality of S. litura larvae than the use of a single extract. The aims of the research were to know the efficacy of the mixed of experimental extracts on the mortality of S. litura larvae and determine the value of LC50 and LC90 extract test on its mortality. The initial and efficacy test were conducted by bait dip into the mixed of experimental extracts. The mortality data were analyzed using ANAVA, then continued by Duncan test and Probit analysis. The results of this research showed that the mixed of experimental extracts were effective to kill S. litura larvae. The calculated result of LC50 and LC90 showed that the LC50 value of the experimental extracts on the second and the third instar larvae were 5.252 ppm and 10.559 ppm, respectively, and the LC90 value for both instar larvae were 11.124 ppm and 13.638 ppm, respectively. It could be concluded that the mixed of experimental extracts is effective in S. litura larvae mortality and more effective in the mortality of the second instar larvae than that of the third instar larvae. Therefore, this test extract mixture can be developed further in a greenhouse to evaluate the effectiveness in the mortality of S. litura larvae which can be used as an alternative to controlling S. litura larvae with an environmentally friendly material in farmers. Keywords: control, extract, mortality, Spodoptera litura

Chemical Composition and Larvicidal Activities of Essential Oils of Medicinal Plants, Artemisia Sieberi and Tanacetum Balsamita Against Malaria Vector, Anopheles Stephensi

Background: The country is suffering from malaria disease. There are several chemical control of mosquito. Due to resistant of vectors to different pesticides, this research was conducted to measure the chemical components and larvicidal activities of two native plants, Artemisia sieberi and Tanacetum balsamita against Anopheles stephensi.Materials and methods: Two species of medicinal plants were collected from different localities in in Iran. The plant samples were dried in shaded place and Essential Oils (EO) dried over anhydrous sodium sulfate. The EOs was maintained in the dark sealed vials until conduction larvicidal tests. The maximum storing of EOs was two days. The larvicidal tests were carried out based on the guideline of WHO. Results: The values of LC50 and LC90 of EOs were 47.9 and 178.8 ppm for Artemisia sieberi. The figure of 26.2and 52.4 ppm was observed for Tanacetum balsamita.The chemical constituents of Tanacetum balsamita and Artemisia sieberi which showed the highest efficacy for larviciding. A total of 39 constituents were isolated from Tanacetum balsamita .The main constituents were Thujone (52.37%) and Carvone (26.84%). Totally 57 constituents were detected in Artemisia sieberi and the main components were : camphor (23.6%) , 2-Ethyl-3- methyl maleic anhydride (15. 193%) and, Bombykal (10.32%) , Ethylbutenol (10.74%) .Conclusion: New formulations of plants should be prepared and then evaluated under semi-filed and filed conditions in a malrious areas.