Production of Natural Insecticide on Management of Plutella xylostella (Linnaeus, 1758) (Lepidoptera: Plutellidae) in Family Farming

Collard greens are commonly grown in family farming systems; however, damage caused by the diamondback moth Plutella xylostella (Lepidoptera: Plutellidae) reduces yields, leading to successive applications of insecticides and consequently, environmental and toxicological problems. Therefore, it is essential to search for alternatives that reduce the use of pesticides and are economically viable and accessible to small farmers. This study was aimed at evaluating the insecticidal activity of aqueous extracts of neem and tobacco on P. xylostella. First instar caterpillars were offered collard leaf discs treated with different concentrations (30 caterpillars per treatment) and after the third day, mortality was evaluated. To evaluate ovicidal properties, collard leaves with 30 eggs were immersed in extracts and after 48 h, viability was measured. Oviposition deterrent activity was assessed with 23 couples of P. xylostella released in cages (repetitions) containing treated collard plants and after 48 h, the number of eggs per plant was recorded. Neem and tobacco extracts exhibited larvicidal, ovicidal, and oviposition deterrent properties against P. xylostella, indicating that the use of these extracts may be promising alternatives in family farming systems.

Transcriptome Analysis of Aedes albopictus (Diptera: Culicidae) Larvae Exposed With a Sublethal Dose of Haedoxan A

Aedes albopictus is the vector of arbovirus diseases including yellow fever, dengue, Zika virus, and chikungunya fever, and it poses an enormous threat to human health worldwide. Previous studies have revealed that haedoxan A (HA), which is an insecticidal sesquilignan from Phryma leptostachya L., is a highly effective natural insecticide for managing mosquitoes and houseflies; however, the mechanisms underlying the response of Ae. albopictus after treatment with sublethal concentrations of HA is not clear. Here, high-throughput sequencing was used to analyze the gene expression changes in Ae. albopictus larvae after treatment with the LC30 of HA. In total, 416 differentially expressed genes (DEGs) were identified, including 328 upregulated genes and 88 downregulated genes. Identification and verification of related DEGs were performed by RT-qPCR. The results showed that two P450 unigenes (CYP4C21 and CYP304A1), one carboxylesterase, and one ABC transporter (ABCG1) were induced by HA, which indicated that these detoxifying enzyme genes might play a major role in the metabolic and detoxification processes of HA. Additionally, acetylcholine receptor subunit ɑ2 (AChRα2), AChRα5, AChRα9, and the glutamate receptor ionotropic kainate 2 (GRIK2) were found to be upregulated in HA-treated larvae, suggesting that HA affected the conduction of action potentials and synaptic transmission by disrupting the function of neural receptors. These results provide a foundation for further elucidating the target of HA and the mechanism of detoxification metabolism in Ae. albopictus.

Spanish chamomile (Anacyclus pyrethrum) and pyrethrum (Tanacetum cineraiifolium): organic and natural pesticides and treasure of medicinal herbs

Pyrethrum (Tanacetum cineraiifolium) which is a natural insecticide has many properties, but the most important are raid action, very low toxicity for mammalian, lack of insect immunity, broad of activity, lack of persistence and degraded quickly by UV in sunlight and very effective insect repellent. Organic farmers can use pyrethrins as an insecticide for fruit and vegetable crops. Easily degraded by oxygen, light and temperature, pyrethrum compounds are environmentally friendly and compatible with organic farming. A. pyrethrum roots contain anacyclin, pellitorine, hydrocarolin, inulin, traces of volatile oil and seasamin. The roots of A. pyrethrum are used in traditional medicine of different countries to treat epilepsy, rheumatism, cephalalgia, paralysis and hemiplegia. N-alkylamids and ester pyrethrine are the main constituents of roots which have tremendous medicinal values. The plant is also a natural pesticide with considerable antimicrobial properties. It has also possessed antidepressant, anti-inflammatory, anticonvulsive, antimicrobial, local anaesthetic, oxidative DNA damage preventive, immunostimulatory, saliva-stimulating, male libido enhancing, anti-mutagenesis and insecticidal activities.

Insecticidal activity ofGallesia integrifolia (Phytolaccaceae) essential oil

This study evaluated the insecticidal activity of Gallesia integrifoliaessential oil from fruits, leaves, and flowers against Aedes aegyptilarvae and pupae. The essential oil was obtained by hydrodistillation and characterized by gas chromatography-mass spectrometry. Sulfur compounds represented 95 to 99% of the essential oil from fruits, leaves, and flowers. Essential oil major compounds were 2,8-dithianonane (52.6%) in fruits, 3,5-dithiahexanol-5,5-dioxide (38.9%) in leaves, and methionine ethyl ester (45.3%) in flowers. The essential oils showed high activity against larvae, and low for pupae withLC99.9of 5.87 and 1476.67μg/mL from fruits; 0.0096 and 348.33 μg/mL from leaves and 0.021and 342.84 μg/mL from flowers, respectively. The main compound with insecticide activity is probably n-ethyl-1,3-dithioisoindole, from isoindole organothiophosphate class, found in greater amount in flower and leaf essential oil. The great insecticide activity of G. integrifoliaessential oil suggests that this product is a natural insecticide.

EFFECTS OF HIBISCUS ROSA SINENSIS AND CYMBOPOGON CITRATUS AGAINST APHIDS : A REVIEW

Aphids are the major pest on crops. Use of chemical pesticides create problems. Chemical pesticides affect the human health, environment and also affects non target organisms. Natural insecticide produced from plants are more promising. The Cymbopogon citratus and Hibiscus rosa sinensis are very important plant which have great effect on insects. The aim of this review to tell about essential oil and extracts which affects insect growth and how much it is effective. The problem of agriculture crop was pests and these pests are responsible for damaging crops and effect nutritive value. Lemon grass oil repels insects like mosquitoes, aphids due to which it contains citral and also myrcene, citronella, citronellol, and geraniol. The essential oil is derived from aromatic plants has observed as risk free alternatives.

Derris elliptica (tuba root).

Derris elliptica is a large and fast-growing climber that is cultivated primarily across tropical regions of the world for its roots, which are used as fish poison and as the source of the natural insecticide rotenone. This species is adapted to a wide range of climates and soil types and spreads sexually by seed and vegetatively by stem fragments. It has successfully escaped from cultivation to become naturalized principally in disturbed areas and secondary forests. D. elliptica often behaves as an aggressive weed and, once established, climbs over other trees and shrubs forming a dense canopy that smothers vegetation, fences, forests, pastures, plantations and cultivated land. D. elliptica is now listed as invasive in Fiji, French Polynesia, Hawaii, Palau, Japan and Cuba.