Extraction, Chemical Composition and Insecticidal Activities of Lantana camara Linn. Leaf Essential Oils against Tribolium castaneum, Lasioderma serricorne and Callosobruchus chinensis

Storage pests and the food spoilage they cause are problems of great concern. Using essential oil obtained from different plants as an insecticide against these storage pests can be considered an environmentally friendly pest management option. Lantana camara Linn. (family Verbenaceae) is a flowering species, and is also a noxious weed that can proliferate well in nearly all geographical habitats. A biopesticide derived from the essential oil extracted from this plant can offer an effective solution for controlling storage pests. The goal of this study is to extract and analyse the chemical composition of essential oil obtained from L. camara leaves, and assess its effectiveness as a bioactive substance against three storage pests: Tribolium castaneum, Lasioderma serricorne, and Callosobruchus chinensis. The yield of essential oil extracted from L. camara leaves was about 0.24 ± 0.014%. By employing the GC-MS technique, the major phytochemicals contained in L. camara leaf essential oil were identified as caryophyllene (69.96%), isoledene (12%), and α-copaene (4.11%). The essential oil exhibited excellent fumigant toxicity (LC50 of 16.70 mg/L air for T. castaneum, 4.141 mg/L air for L. serricorne and 6.245 mg/L air for C. chinensis at 24 h), contact toxicity (LC50 of 8.93 mg/cm2 for T. castaneum, 4.82 mg/cm2 for L. serricorne and 6.24 mg/cm2 for C. chinensis after 24 h) along with effective repellent activity towards the test insects. In addition, the oil showed no significant phytotoxicity on the germination of paddy seeds. This presents the potential to utilize a weed in developing a biopesticide for effectively managing stored product insects because of its strong bioactivity

Preparation of Lambda-Cyhalothrin-Loaded Chitosan Nanoparticles and Their Bioactivity against Drosophila suzukii

The encapsulation of pesticides within nanoparticles is a promising approach of advanced technology in sustainable agriculture. Lambda-cyhalothrin (LC) was encapsulated by the ionotropic gelation technique into chitosan (CS)/tripolyphosphate (TPP) and CS/alginate (ALG) matrixes. CS-LC nanoparticles were characterized, and their efficacy was then evaluated against the key pest of soft fruits in Europe and the United States, Drosophila suzukii. The encapsulation efficiency (74%), nanoparticle yield (80%), polydispersity index (0.341), zeta potential (-23.1 mV) and particle size (278 nm) were determined at the optimum conditions. FTIR confirmed the cross-linkage between CS and TPP/ALG in the nanoparticles. The optimum formula recommended by the fractional factorial design was associated with the formulation variables of CS of high or low molecular weight, cross-linking agent (TPP), LC concentration (1.5% w/v) and stirring rate (1500 rpm), showing the highest desirability value (0.5511). CS-LC nanoparticles of the lowest particle size (278 nm) exhibited the highest percent mortality of D. suzukii males (86%) and females (84%), exceeding that caused by the commercial product (Karate-zeon® 10% CS) at 2 HAT. This is the first work to use the ionic gelation technique to make LC nanoparticles, to the best of our knowledge. The encapsulation of chemical pesticides within biodegradable polymeric nanoparticles could be helpful for establishing a sustainable IPM strategy with benefits for human and environmental health and the lifetime of pesticides

Efficiency of Bacillus thuringiensis and Bacillus cereus against Rhynchophorus ferrugineus

The Red Palm Weevil (Rhynchophorus ferrugineus (Oliv.) (Coleoptera, Dryophthoridae) is a well-known palm tree pest that has caused enormous economic damage all over the globe. Insecticides are still the primary method of controlling this pest at this period. However, field populations of RPW have been shown to be resistant to pesticides. Using Bacillus spp. might be one of the options for controlling R. ferruginous. In this study, 23 species of Bacillus spp. were isolated from the rhizosphere of date palm trees in Al Ahsa Oasis, Saudi Arabia. The isolates were identified using 16S rRNA gene sequencing. R. ferrugineus larvae and adults were tested on sugarcane pieces that were treated with the B. thuringiensis strain PDC-AHSAA1 and B. cereus strains (PDC-AHSAA2, PDC-AHSA3 and PDC-AHSA4). The LC50 values for larvae and adults were quite low when they were compared with those of the other isolated strains. The B. thuringiensis strain PDC-AHSAA1 was more effective against both the larvae and adults. The determined LC50 values for B. thuringiensis ranged from 4.19 × 107–3.78 × 109. After 21 days, the data on larval mortality and body weight were evaluated. The surviving larvae that were treated with the bacterial isolates did not acquire a substantial weight. For the RPW larvae and adults, the mortality and corrected mortality death rates were increased by increasing the concentration of B. thuringiensis. In conclusion, Bacillus-treated diets negatively influenced the growth and development of the RPW. This research reported on the interaction between the RPW and the rhizosphere Bacillus spp. and highlighted the tremendous potential for the development of microbial resource-based control strategies for this pest

Novel Pesticidal Efficacy of Araucaria heterophylla and Commiphora molmol Extracts against Camel and Cattle Blood-Sucking Ectoparasites

Botanical insecticides are promising pest control agents. This research investigated the novel pesticidal efficacy of Araucaria heterophylla and Commiphora molmol extracts against four ectoparasites through treated envelopes. Seven days post-treatment (PT) with 25 mg/mL of C. molmol and A. heterophylla, complete mortality of the camel tick, Hyalomma dromedarii and cattle tick, Rhipicephalus (Boophilus) annulatus were reached. Against H. dromedarii, the median lethal concentrations (LC50s) of the methanol extracts were 1.13 and 1.04 mg/mL and those of the hexane extracts were 1.47 and 1.38 mg/mL, respectively. The LC50 values of methanol and hexane extracts against R. annulatus were 1.09 and 1.41 plus 1.55 and 1.08 mg/mL, respectively. Seven days PT with 12.5 mg/mL, extracts completely controlled Haematopinus eurysternus and Hippobosca maculata; LC50 of Ha. eurysternus were 0.56 and 0.62 mg/mL for methanol extracts and 0.55 and 1.00 mg/mL for hexane extracts, respectively, whereas those of Hi. maculata were 0.67 and 0.78 mg/mL for methanol extract and 0.68 and 0.32 mg/mL, respectively, for hexane extracts. C. molmol extracts contained sesquiterpene, fatty acid esters and phenols, whereas those of A. heterophylla possessed monoterpene, sesquiterpene, terpene alcohols, fatty acid, and phenols. Consequently, methanol extracts of C. molmol and A. heterophylla were recommended as ecofriendly pesticides

Data from: Experimental swap of Anopheles gambiae's assortative mating preferences demonstrates key role of X-chromosome divergence island in incipient sympatric speciation.

Although many theoretical models of sympatric speciation propose that genes responsible for assortative mating amongst incipient species should be associated with genomic regions protected from recombination, there are few data to support this theory. The malaria mosquito, Anopheles gambiae, is known for its sympatric cryptic species maintained by pre-mating reproductive isolation and its putative genomic islands of speciation, and is therefore an ideal model system for studying the genomic signature associated with incipient sympatric speciation. Here we selectively introgressed the island of divergence located in the pericentric region of the X chromosome of An. gambiae s.s. into its sister taxon An. coluzzii through 5 generations of backcrossing followed by two generations of crosses within the introgressed strains that resulted in An. coluzzii-like recombinant strains fixed for the M and S marker in the X chromosome island. The mating preference of recombinant strains was then tested by giving virgin recombinant individuals a choice of mates with X-islands matching and non-matching their own island type. We show through genetic analyses of transferred sperm that recombinant females consistently mated with matching island-type males thereby associating assortative mating genes with the X-island of divergence. Furthermore, full-genome sequencing confirmed that protein-coding differences between recombinant strains were limited to the experimentally swapped pericentromeric region. Finally, targeted-genome comparisons showed that a number of these unique differences were conserved in sympatric field populations, thereby revealing candidate speciation genes. The functional demonstration of a close association between speciation genes and the X-island of differentiation lends unprecedented support to island-of-speciation models of sympatric speciation facilitated by pericentric recombination suppression

SNP Data Mopti, RbMM, RbSS strains and 2 field populations

SNPs identified by full-genome sequencing for Mopti, RbMM, RbSS strains and targeted sequencing of X-island for 2 An. coluzzii and gambiae s.s. populations from Ghana. The files were generated by GATK (VCF format)

Field population frequency distribution of protein coding SNPs identified in RbSS.

<p>A region covering the X-island and flanking region up to reference position 17Mbp was captured and re-sequenced in sympatric <i>An</i>. <i>gambiae</i> s.s. and <i>An</i>. <i>coluzzii</i> populations from Ghana. The frequency of alleles coding for unique protein differences in the RbSS recombinant strain was measured in the field <i>An</i>. <i>gambiae</i> s.s. population. The proportion of alleles occurring at high 0.8 (orange bars) and very high (freq >0.95: red bars) frequency increased towards the centromere suggesting a potential role in speciation whilst other alleles (blue bars) were not conserved (see text for details).</p

Genomic structure of recombinant strains.

<p>The genomes of the assortatively-mating RbMM, RbSS and parental Mopti strains were compared using <i>F</i>_ST estimates at ~3x10⁶ SNP marker loci (left Y-axis and red, blue and black lines). The genomic region introgressed from Kisumu into the Mopti genetic background and differing between the RbMM and RbSS recombinant strains is characterized by high <i>F</i>_ST values (blue shade) and extends from position ~14.5Mb to the centromere on chromosome X. The RbMM and RbSS differed at 160 protein-changing positions all of which located within the introgressed island and flanking region (right Y-axis, grey histogram bars). The pericentromeric region sharing conserved fixed differences with the field <i>Anopheles coluzzii and gambiae s</i>.<i>s</i> populations starts at position ~18.1Mb (orange shade). The position of inversions <i>c</i>, <i>u</i> and <i>a</i> on chromosome 2 is indicated (pink shade).</p

Recombinant and parental strains genotypes at the X, 2L and 3L divergence islands, and 2L and 2R inversion karyotypes.

<p>Genotypic and inversion frequencies and sample sizes are shown for the M Mopti and S Kisumu parental strains as well as the RbMM and RbSS recombinant strains.</p><p>Recombinant and parental strains genotypes at the X, 2L and 3L divergence islands, and 2L and 2R inversion karyotypes.</p