Ayesha Afzal

Fall armyworm, Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae), is a polyphagous insect pest of many important crops. To evaluate the influence of host plants on the biology and survival of the Pakistani population of S. frugiperda, we examined life table parameters of S. frugiperda raised on maize, sorghum, wheat, and rice. The development rate was significantly higher on the maize crop than on the other three host plants. Different larval diets affected development time and fecundity. S. frugiperda attained the fastest larval development (16 days) on maize and the slowest development (32.74 days) on rice. Adult females from maize-fed larvae laid 1088 eggs/female, those from sorghum-fed larvae laid 591.6 eggs/female, those from wheat-fed larvae laid 435.6 eggs/female, and those from rice-fed larvae laid 49.6 eggs/female. Age stage-specific parameters also indicated the higher fecundity, higher life expectancy, and higher survival of S. frugiperda on maize plants than on the other three hosts. Larval diets had a significant varying effect on the finite and intrinsic increase rates, reflecting that maize was the most suitable diet. The findings of the present study are useful for predicting population dynamics especially in areas cultivating Poaceae crops, except maize, to develop sustainable integrated pest management strategies for this pest.

Fall armyworm [Spodoptera frugiperda (J. E. Smith, 1797)] was first reported in the Americas, then spread to all the continents of the world. Chemical insecticides are frequently employed in managing fall armyworms. These insecticides have various modes of actions and target sites to kill the insects. Chlorantraniliprole is a selective insecticide with a novel mode of action and is used against Lepidopteran, Coleopteran, Isopteran, and Dipteran pests. This study determined chlorantraniliprole’s lethal, sub-lethal, and trans-generational effects on two consecutive generations (F₀, F₁, and F₂) of the fall armyworm. Bioassays revealed that chlorantraniliprole exhibited higher toxicity against fall armyworms with a LC₅₀ of 2.781 mg/L after 48 h of exposure. Significant differences were noted in the biological parameters of fall armyworms in all generations. Sub-lethal concentrations of chlorantraniliprole showed prolonged larval and adult durations. The parameters related to the fitness cost in F₀ and F₁ generations showed non-significant differences. In contrast, the F₂ generation showed lower fecundity at lethal (71 eggs/female) and sub-lethal (94 eggs/female) doses of chlorantraniliprole compared to the control (127.5–129.3 eggs/female). Age-stage specific survival rate (S_xj), life expectancy (E_xj) and reproductive rate (V_xj) significantly differed among insecticide-treated groups in all generations compared to the control. A comparison of treated and untreated insects over generations indicated substantial differences in demographic parameters such as net reproduction rate (R₀), intrinsic rate of increase (r), and mean generation time (T). Several biological and demographic parameters were shown to be negatively impacted by chlorantraniliprole. We conclude that chlorantraniliprole may be utilized to manage fall armyworms with lesser risks.

Sucking pests of cotton (Gossypium hirsutum L.), such as thrips, or Thrips tabaci Lindeman, and jassid, or Amrasca biguttula Ishida, are among the most threatening insect pests to young cotton plants in Pakistan. New chemical insecticides have been trialed to control their damage in commercial fields. Formulations that show good suppression of these pest’s populations, while sparing bio-controlling agents, are always preferred for obtaining better crop yield. Six different commercially available insecticides, namely Fountain^® (fipronil and imidacloprid), Movento Energy^® (spirotetramat and imidacloprid), Oshin^® (dinotefuran), Concept Plus^® (pyriproxyfen, fenpyroximate, and acephate), Maximal^® (nitenpyram), and Radiant^® (spinetoram) were evaluated in the present study to shortlist the best available insecticide against targeted pests. Harmful impacts of selected insecticides were also evaluated against naturally occurring predators, such as spiders and green lacewings (Chrysoperla carnea). Radiant^® (spinetoram) and Movento Energy^®, respectively, were best at controlling thrips (with 61% and 56% mortality, respectively) and jassid (62% and 57% mortality, respectively) populations during 2018 and 2019. Radiant^® proved itself as the best option and showed minimal harmful effects on both major arthropod predators of cotton fields i.e., spiders (with 8–9% mortality) and green lacewings (with 12–16% mortality). Movento Energy^® also showed comparatively less harmful effects (with 15–18% mortality) towards natural predatory fauna of cotton crops, as compared to other selective insecticides used in the study. The findings of current study suggest that the judicious use of target-oriented insecticides can be an efficient and predator-friendly management module in cotton fields. However, the impact of these chemicals is also depended on their timely application, keeping in consideration the ETL of pests and the population of beneficial arthropods.

The physiological and biochemical characterization of the “Halloween” genes has fundamental importance in the biosynthesis pathway of ecdysteroids. These genes were found to catalyze the final phases of ecdysteroid biosynthesis from dietary cholesterol to the molting hormone 20-hydroxyecdysone. We report the characterization of the Cs-Phm in a major insect pest in agriculture, the rice striped stem borer, Chilo suppressalis (C. suppressalis). A full-length transcript of Cs-Phm was amplified with an open reading frame (ORF) of 478 amino acids through 5′ and 3′ RACE. Cs-Phm shows five insect-conserved P450 motifs: Helix-C, Helix-I, Helix-K, PERF, and heme-binding motifs. Phylogenetic analysis clearly shows high similarity to Lepidoptera and evolutionary conservation in insects. The relative spatial and temporal transcript profile shows that Cs-Phm is highly expressed in the prothoracic glands and appears throughout the larval development, but with low expression at the start of the larval instar. It seems to peak in 3–4 days and decreases again before the larvae molt. Double-stranded RNA (dsRNA) injection of Cs-Phm at the larval stage efficiently knocked down the target gene and decreased its expression level. The dsRNA-treated group showed significantly decreased ecdysteroid titers, which leads to delayed larval development and higher larval mortality. Negative effects of larval development were rescued by treating 20E in the dsRNA-treated group. Thus, in conclusion, our results suggest that Cs-Phm is functionally conserved in C. suppressalis and encodes functional CYP that contributes to the biogenesis of 20E.

The control of Spodoptera frugiperda, the key invasive pest of maize, is a serious concern due to its biology and the current global restriction on applying synthetic pesticides. Entomopathogenic fungi are considered to be a potential biological control strategy. The pathogenicity of 12 isolates of Beauveria bassiana in the immature stages and feeding efficacy of S. frugiperda were evaluated. The B. bassiana isolates QB-3.45, QB-3.46 and QB-3.428 caused the highest egg mortality rates of 87.3, 82.7 and 79.3%, respectively, when applied at a concentration of 1 × 10⁸ conidia/mL and measured at 7 days post-treatment. Neonate mortality rates of 45.6 to 53.6% were observed with the same isolates. The B. bassiana isolates caused significant cumulative mortality rates ranging from 71.3 to 93.3% at 14 days post-treatment and reduced larval feeding efficacy from 69.4 to 77.8% at 48 h post-treatment. This study supports using the effective B. bassiana isolates as a biological control agent against S. frugiperda. The significant mortality of the eggs and neonatal larvae and the reduction in the feeding efficacy of the second instar larvae of the S. frugiperda that were treated with isolates of B. bassiana supports the application of entomopathogenic fungi as a biocontrol agent for the effective control of the S. frugiperda population.

Fall armyworm, Spodoptera frugiperda (JE Smith) (Lepidoptera: Noctuidae), is a destructive pest of a wide array of agricultural and horticultural crops worldwide. This in vitro research assessed the combined effect of methanolic extracts of indigenous flora of Soone Valley (Khushab, Pakistan) and nine commonly used synthetic insecticides against 3rd instar larvae of S. frugiperda using the leaf-dip bioassay method. Toxicity bioassays with twelve plant extracts revealed that the extracts of Withania somnifera (L.) Dunal, Sophora mollis (Royle) Baker and Rhazya stricta Decne. were the most effective, exhibiting minimum LC₅₀ and LT₅₀ values. Bioassays with synthetic insecticides revealed a significantly higher mortality of S. frugiperda larvae by emamectin benzoate (45%), chlorpyrifos (40%) and chlorantraniliprole (38%). Further bioassays with 10 binary combinations of these most effective botanical and synthetic insecticides showed that seven pesticidal combinations exhibited synergistic toxicity, and three combinations comprising emamectin benzoate exhibited an additive effect on the mortality of S. frugiperda larvae. GC–MS analyses of methanolic extracts of W. somnifera, S. mollis and R. stricta revealed 1,2,4-trimethyl-benzene and 3,5-dimethyl-octane, 1-ethyl-2-methyl-benzene, and 1-monolinoleoylglycerol trimethylsilyl ether, decane, and lupeol as major bioconstituents, respectively. Our results demonstrated that combining botanicals with synthetic insecticides can synergize their toxicity against S. frugiperda larvae, suggesting their potential incorporation into future IPM programs against S. frugiperda and other lepidopterous pests.

Maize is the most essential crop of China and its productivity has been recently endangered by the fall armyworm (FAW),Spodoptera frugiperda. Chemical pesticides are one of the most important strategies for managing FAW on a short-term basis. The seven synthetic insecticides including novel and conventional belong to four chemical group, spinetoram and spinosad (spinosyns), lambda-cyhalothrin, cypermethrin and bifenthrin (pyrethroids), abamectin (avermectins), broflinilide (diamides), were assessed for their efficiency in causing mortality to second instarS.frugiperdalarvae at 24, 48 and 72 h post-treatment at five different serial concentrations (10 to 0.625 mg liter^-1). The second instarS.frugiperdalarvae were susceptible to the tested synthetic insecticides, however, the toxicity index of synthetic insecticides was estimated based on lethal concentration 50 (LC₅₀), while, LC₅₀was calculated from the data of larval mortality. The broflanilide and abamectin proved to be the most toxic having the highest toxicity index of 100 and 78.29%, respectively, followed by cypermethrin and bifenthrin were showed toxicity index of 75.47 and 66.89%, respectively. The LC₅₀values were 0.606 and 0.774 mg liter^-1for broflanilide and abamectin, respectively, followed by cypermethrin and bifenthrin were showed LC₅₀values of 0.803 and 0.906 mg liter^-1at 72 h post-treatment. Rest of the other synthetic insecticides were showed moderate toxicity index of 42.11 to 62.09%, based on LC₅₀values were 1.439 to 0.976 mg liter^-1at 72 h post-treatment. The efficiency of synthetic insecticides was increased by increasing concentration level and exposure time. The screened synthetic insecticides among seven insecticides perhaps, provide basis for the development of novel insecticides for controllingS.frugiperdapopulation after further research to evaluate and validate the laboratory results in the field.

Maize is a major staple crop in China, and the sustainable productivity of this primary crop has been recently threatened by fall armyworm (FAW), Spodoptera frugiperda, invasion. The five fungal isolates, Aspergillus sp. BM-3 and SE-2-1, Cladosporium tenuissimum SE-10, Penicillium citrinum CTD-24, and Beauveria bassiana ZK-5 were assessed for their efficacy in causing mortality against first to sixth instar eggs and neonate larvae seven days post-treatment, and their effects on the feeding performance of sixth instar S. frugiperda larvae at 48 h post-treatment at three concentrations (1 × 10⁶, 1 × 10⁷, and 1 × 10⁸ conidia mL⁻¹) were also assessed. The six instar S. frugiperda larvae were not susceptible to the five tested fungal isolates. However, B. bassiana ZK-5 caused the highest egg mortality of 40, 70, and 85.6% at 1 × 10⁶, 1 × 10⁷, and 1 × 10⁸ conidia mL⁻¹, respectively, followed by P. citrinum CTD-24 (30.6, 50, and 75.6%) and C. tenuissimum SE-10 (25.6, 40, and 55.6%). In addition, B. bassiana ZK-5 caused the highest neonate mortality of 54.3% at 1 × 10⁸ conidia mL⁻¹. B. bassiana ZK-5 and P. citrinum CTD-24 caused cumulative mortality, including 93.3 and 83.3% mortality of eggs and neonates, respectively, at 1 × 10⁸ conidia mL⁻¹. Furthermore, B. bassiana ZK-5 reduced the feeding efficacy of first to third instar S. frugiperda larvae by 66.7 to 78.6%, while P. citrinum CTD-24 and C. tenuissimum SE-10 reduced larval feeding by 48.3 to 57.1% at 1 × 10⁸ conidia mL⁻¹. However, these fungal isolates were less potent in reducing the feeding activity of fourth to sixth instar S. frugiperda larvae (>46% with B. bassiana at 48 h post-treatment). The tested fungal isolates could play an essential role as microbial biopesticides in suppressing the S. frugiperda population in China after further investigations on their efficacy are obtained in the field.

Background: To study the hepatoprotective effect of Ethanolic extract of Stem Bark of Berberis lycium Royale in isoniazid (INH) induced hepatotoxicity in mice model.Methods: The study design was lab based randomized controlled in-vivo study in mice conducted from 9th April 2014 till 9th May 2014 at animal house of National Institute of Health, Islamabad. Group A was on normal diet and water and hepatotoxicity was produced by giving isoniazid (50mg/kg BW) in mice of Group B. Group C and D were given isoniazid (INH) plus low dose and high dose of Ethanolic extract of stem bark of Berberis Lycium Royle respectively.Results: INH induced hepatotoxicity was depicted by elevated serum LFT’s, hepatocytic ballooning, severe steatosis and inflammation. Mice getting concurrent treatment of INH, low and high dose of Ethanolic extract of Berberis Lycium Royle showed decreased serum levels of biomarkers and their liver sections manifested improved histological picture but more significant reduction in toxic effects were observed in animals receiving high dose.Conclusions: High dose of Ethanolic extract of stem bark of Berberis lycium Royale showed more marked hepatoprotective activity as compare to low doses. The hepatotoxicity of INH can be reduced by concurrent use of INH with ethanolic extracts of Berberis Lycium Royle.