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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]

Subterranean termites are devastating pests of many agricultural and horticultural crops, forest plantations and wooden infrastructures. Farmers rely primarily on direct applications of liquid insecticides which usually get off the target site resulting in unsatisfactory and short-term termite eradication along with environmental contaminations. This situation necessitates looking for more target-oriented and ecologically safer strategies such as baiting insecticides with some cellulose attractant. In this study, 5% technical grade fipronil was formulated as small beads (3.5 mm) made by a matrix composed of 65% maize cob powder (as source of natural cellulose for termite attraction), 18% starch, 6% sodium alginate, 4% sodium silicate, and 2% urea. Termites infested monitoring stations installed in a sugarcane field were treated with the formulated bait beads and were inspected for termite activity at 15 and 30 days post-treatment. Results of initial in-vitro trials indicated that formulated beads remained intact and did not disintegrate by consecutive episodes of wetting and drying and were able to attract more than 50% termite individuals exposed. This formulation suppressed the termites in field as no termite foraging was recorded inside the bait-treated monitoring stations for about a month post-treatment, while the termites fed on all beads in the control monitoring stations. Overall study findings validate the effectiveness of fipronil and formulated beads for their potential incorporation in the management of subterranean termites in agricultural crops. However, further studies are needed to get more empirical data regarding the formulation's effectiveness and to determine the insecticide (fipronil) release kinetics from the formulated beads under laboratory and field conditions. [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]

Subterranean termites are destructive pests of agricultural crops, forest and orchard plantations and wooden infrastructures. A wide range of persistent synthetic chemicals are employed to prevent and control the infestations of subterranean termites. Most of these chemicals have high mammalian toxicity and environmental hazards. This study was, therefore, aimed to evaluate the efficacy of some promising botanical extracts (Dodonaea viscosa, Gardenia jasminoides and Nerium indicum), plant essential oils (Allium sativum, Citrus aurantium and Cymbopogon citratus) and differential-chemistry insecticides (chlorantraniliprole, chlorfenapyr, emamectin, indoxacarb, pyriproxyfen and triflumuron) against subterranean termites (Odontotermes obesus) attacking sugarcane crop. Setts of sugarcane variety HSF555 were sown on the ridges under RCB design after treating them with 20% botanical extracts, 2.0% essential oils and differential-chemistry insecticides with their field recommended dose rates. Results revealed that as compared to control plots, all treatment plots exhibited reduced bud and shoot damage with maximum bud germination and minimum termite infestation. Maximum bud germination was recorded in chlorantraniliprole (92.99%) and chlorfenapyr (92.03%), followed by C. aurantium (92.84%) and A. sativum (85.78%) as compared to minimum bud germination in control (40.85%). Highest bud and shoot damage was recorded in control (61.92 and 48.15%, respectively), while the lowest was recorded in C. aurantium (16.18 and 15.56%, respectively). Similarly, minimum per sett termite counts was recorded in chlorantraniliprole (16.25) treated plots, followed by chlorfenapyr (22.83), pyriproxyfen (30.04), A. sativum (28.50) and C. aurantium (29.00), while maximum termite infestation was recorded in control (68.50 individuals per sett). In brief, chlorantraniliprole, chlorfenapyr and pyriproxyfen among differential-chemistry insecticides and A. sativum, C. aurantium and G. jasminoides among botanicals were the most effective at preventing the upsurge of termite infestation till 90 days of sett sowing, and are recommended to be used as eco-friendly options for controlling subterranean termites in sugarcane. [ABSTRACT FROM AUTHOR]