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The fall armyworm, Spodoptera frugiperda (J. E. Smith), is a destructive pest of Zea mays (maize) and other agricultural crops. The synthetic insecticides predominantly used against this pest lead to pest resistance, environmental contamination and health hazards. This study evaluated nanoformulated aqueous extracts of some promising local plant species against third instar larvae of S. frugiperda under laboratory and field conditions. The initial screening bioassay showed highest larval mortality with a 20% extract of Nicotiana tabacum L. (66.67%), followed by Azadirachta indica A. Juss. (53.33%), Withania somnifera L. (46.67%), Melia azedarach L. (40%) and Dodonaea viscosa Jacq. (33.33%). The two most effective plant extracts (A. indica and N. tabacum) were further nanoformulated with silver nitrate (AgNO3) and bioassayed against S. frugiperda larvae using different concentrations. The results showed that these nanoformulated extracts caused significant larval mortality, with LC50 (lethal concentration that kills 50% of the population) and LT50 (lethal time to kill 50% of the population) values of 37.36 and 28.21% at 72 h, and 52.19 and 33.25 h at 80% concentration, respectively. Field experiments on Zea mays L. (maize) plants showed maximum larval reduction by nanoformulated A. indica extract (48%), followed by N. tabacum extract (36%), whereas 80% and 20% larval reduction was noted for the positive (SuperLock®, emamectin benzoate and tebufenozide) and the negative (water) controls, respectively. Furthermore, characterization of both silver nanoparticles‐based plant extract formulations was performed using ultraviolet–visible (UV–vis) spectroscopy, Raman spectroscopy and scanning electron microscopy (SEM) techniques, which confirmed the formation of silver nanoparticles. It is concluded that nanoformulated plant extracts can be an effective alternative to synthetic pesticides in combatting S. frugiperda and other lepidopteran pests. [ABSTRACT FROM AUTHOR]

This study was conducted to investigate weed infestations of cotton (Gossypium hirsutum) fields in the region of Tarim River. Forty‐nine species among 17 families were identified in these cotton fields, and 24 of them were annuals. The eight dominant weed species in the cotton fields of Tarim River basin included Chenopodium glaucum, Solanum nigrum, Chenopodium album, Chenopodium hybridum, Bolboschoenus planiculmis, Sonchus arvensis, Phragmites australis, and Mulgedium tataricum. The number of weed species in the Aksu River tributary area, Yeerqiang River tributary area, and the upper and lower reaches of the Tarim River reached 29, 36, 35, and 33, respectively. Twenty species were found widely distributed among each basin. The dominant weeds in the cotton fields in the Aksu River basin and upper reaches of the Tarim River were S. nigrum and C. glaucum, those in the cotton fields in the Yarkand River basin included C. album and C. hybridum, and those in the cotton fields in the lower reaches of the Tarim River were C. glaucum and C. album. Notably the 20 common surveyed species of C. glaucum, S. nigrum, C. album, C. hybridum, B. planiculmis, S. arvensis, P. australis, M. tataricum, and others, could pose a serious challenge to regional crop production if not adequately controlled. As such, each cotton field should adopt a suitable weeding scheme with strengthened weed monitoring according to the local conditions, especially the weed distribution area characteristics. [ABSTRACT FROM AUTHOR]

Mosquitoes are unquestionably the important arthropod vectors of diseases such as malaria, dengue, filariasis and systemic allergic reactions in humans. Southern house mosquito Culex quinquefasciatus Say is found in tropical and subtropical regions of the world and transmits many zoonotic diseases in humans and in wild and domestic animals. It is primarily controlled by the extensive use of conventional synthetic insecticides against most of which it has developed resistance. This study was aimed at determining the toxicity of selected microbial and synthetic insecticide formulations and botanical extracts against C. quinquefasciatus larvae. Among the n-hexane extracts of 40 indigenous plant species collected from Soon Valley and surrounding salt range of Pakistan bioassayed against C. quinquefasciatus larvae, eighteen botanicals exhibited more than 50% larval mortality in 48 h exposure. The most effective botanical extracts were Maerua arenaria Forsk, Nerium indicum Mill., Withania coagulans Dunal, Suaeda fruticosa (L.) Delile, Olea ferruginea Wall., Adiantum capillus-veneris L. and Dicliptera bupleuroides Nees exhibiting 87, 84, 83, 81, 79, 78 and 77% larval mortality, respectively with minimum LC50 and LC90 values. Among the microbial and synthetic insecticides, the highest larval mortality was recorded by Metarhizium anisopliae NCIM 1311 (83%) and Bacillus thuringiensis subsp. israelensis (63%), and by pyriproxyfen (86%) and indoxacarb (85%), respectively. Hence, these botanical, microbial and synthetic insecticides are recommended for the efficient control of C. quinquefasciatus larvae in field to reduce the environmental pollution caused by persistent synthetic insecticides. [ABSTRACT FROM AUTHOR]

Fruit fly (Bactrocera zonata) is a destructive pest of citrus fruits. Use of synthetic insecticides against fruit fly infestations has created different ecological problems such as the development of insecticide resistance, eradication of beneficial fauna and human health hazards. This situation necessitates looking for alternate biorational fruit fly management tools such as botanical insecticides. This laboratory study was aimed at determining the toxicity of some selected plant extracts (i.e. Azadirachta indica A. Juss., Nigella sativa L. and Citrullus colocynthis (L.) Schrad) alone and as binary combinations against B. zonata adults. The study was conducted in the at Department of Entomology, University of Sargodha, Pakistan in July to September, 2019. Bioassay results showed that aqueous extract of A. indica was most toxic to B. zonata adults with a median lethal concentration (LC50) of 383.3 μl/g of artificial diet, followed by C. colocynthis and N. sativa with LC50 values of 656.3 and 734.2 μl/g of artificial diet, respectively. Bioassays with binary combinations revealed that A. indica with C. colocynthis (ratio 1:1) showed a synergistic effect exhibiting a LC50 value of 293.1 μl/g of artificial diet. However, all other treatment combinations showed an antagonistic effect. It is suggested that the mixture of botanical extracts should be used carefully as they may sometimes reduce the efficacy of each other upon mixing. These results can thus be used in the development of potential botanical formulations against insect pests such as fruit flies. [ABSTRACT FROM AUTHOR]

Sap-sucking insect pests have been a severe threat to horticultural and agricultural crops all over the world. Asian citrus psyllid Diaphorina citri Kuwayama (Psyllidae: Hemiptera) and cotton aphid Aphis gossypii Glover (Aphididae: Hemiptera) are destructive sap-sucking pests of citrus and cotton, respectively. Extensive use of persistent synthetic insecticides against these pests poses issues of environmental contaminations and health hazards and suggests looking for alternate biorational plant protection measures such as botanical pesticides. This study evaluated the potential toxicity of acetone extracts of 40 indigenous plant species of Soon valley and surrounding salt range (Punjab, Pakistan) against D. citri and A. gossypii using standard twig-dip and leaf-dip bioassay methods, respectively. Results of initial screening bioassay showed the highest mortality of D. citri by 10% extracts of Mentha longifolia (L.) Huds. (93%), Melilotus officinalis (L.) Pall. (91%), Nerium indicum Mill. (89%), Datura alba L. (88%) and Salvia officinalis L. (81%). Second bioassay conducted against A. gossypii using different concentrations (5, 10, 20 and 40%) of the most effective botanical extracts revealed that the extract of S. officinalis was most toxic (LC50 = 18.59%), followed by N. indicum (LC50 = 20.27%) and M. longifolia (LC50 = 20.73%). Similar trend of effectiveness was observed regarding their LT50 values. Overall study results demonstrated the biocidal potential of the extracts of indigenous plant species of Soon valley against D. citri and A. gossypii, and suggest their further biochemical characterization and practical implication in future IPM programs against these and other sap-feeding insect pests. [ABSTRACT FROM AUTHOR]

Biopesticides are emerging as eco-friendly control practice against many insect pests. Termites are notorious pests of crops, timber, and trees and the chemical insecticides, hazardous to environment, are used for their control. The current study was aimed at determining the toxicity potential of plants present in Salt Range of Pakistan against subterranean termite, Odontotermes obesus. The extracts of identified plants were prepared with Soxhlet apparatus and rotary evaporator. Screening bioassays were performed to determine the most potent plants under laboratory conditions and toxicity bioassays were carried out to determine the LT50 and LC50 against termites. Out of 40 plant extracts assayed, seven extracts were toxic with more than 50% combined mortality against termites. Salvia officinalis with LC50 of 71 mg/L after 72 h followed by Mentha longifolia, Maerua arenaria, Periploca aphylla, and Rhamnus smithii, Sonchus asper and Nerium indicum were determined as antitermite species. Repellent activity of the extracts was also determined and higher termite control was linked both with toxicity and repellent action of plant extracts. These plants have potential to control the termites and could be used for non-chemical control of termites. [ABSTRACT FROM AUTHOR]

Current study was designed to determine toxicity of heartwood extractives of Albizia lebbeck (L.) Benth. (sirin kala) against subterranean termites. Heartwood was extracted in four solvents and tested to compare mortality, antifeedant/repellency and field protection of poplar wooden stakes treated with these extractives. The highest concentration of ethyl acetate extractive proved to be significantly toxic and repellent to termites when compared with other extractives. Poplar stakes were also protected in field exposure to termites when treated with extractive of ethyl acetate whether dip or vacuum-pressure treated. Organic solvent extractives imparted significant low weight loss than control and water extractives in dipping and vacuum-pressure application. Ethyl acetate protected >2 fold as compared to water and other extractives. [ABSTRACT FROM AUTHOR]