Wafa Abdullah Hamad Alkherb

Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) is a polyphagous insect pest that is responsible for significant financial losses in important crops. Insect growth regulators (IGRs), such as lufenuron, diflubenzuron, and methoxyfenozide, may function as selective pesticides in an integrated pest management (IPM) program for S. frugiperda and other lepidopteran pests. Thus, this study examined the toxicity and biochemical effectiveness of 3 IGR insecticides against second-instar S. frugiperda larvae in laboratory testing. Furthermore, molecular docking analysis was used to assess each compound's binding to the enzymes glutathione-S-transferase (GST) (PDB ID: 1jlv), α-esterase (PDB ID: 4fng), and acetylcholine esterase (AChE) (PDB ID: 6tt0) to identify the molecular mode of action of the IGRs. Toxicity results indicated that lufenuron and diflubenzuron were the most toxic of the 3 IGRs tested against S. frugiperda, followed by methoxyfenozide, based on the median lethal concentration (LC50) values and 95% confidence interval limits. Furthermore, findings showed that treatment with lethal concentrations (LC50) of methoxyfenozide and lufenuron drastically shortened the duration of the larval and pupal stages of S. frugiperda. Compared to the control group, all tested pesticides had an inhibitory impact on AChE, α-esterase, and GST at 24 and 96 h after treatment. The molecular docking analysis revealed that each IGR tested presented a noteworthy propensity for binding to AchE, α-esterase, and GST, with energy scores varying between –4.927 and –7.115 kcal/mol. In addition to offering more effective pest control options for S. frugiperda, these findings should aid in the advancement of knowledge regarding the biochemical and molecular mechanisms of action of the evaluated IGR insecticides.

When stored grains are infested by post-harvest insects, they become unfit for human consumption and cause significant financial losses. We present in our work structural and functional characterization of proteases secreted from Tribolium castanueum (TricaPRO) that was investigated biochemically and by PCR and sequence analysis. Understanding the kinds of enzymes found in Tribolium castanueum is essential for effective management of insect control with appropriate proteinase inhibitor. Serine and cysteine proteinases are the two main kinds of proteinases found in this insect digestive system. An open reading frame of 792 bp translated to 263 amino acid residues was revealed by analyzing the results of the protease gene amplification from the entire adult genome using specific primers based on the NCBI projected sequence. The bioinformatics analyses showed that the deduced amino acid sequence likely corresponds to protease closely related to insect. The sequence analysis by BLAST in the NCBI databases showed high similarity scores revealing that the TricaPRO sequence shares identity rates of 72.69 % with brachyurin-like of Tribolium madens (XP_044267572.1) and 58 % with brachyurin-like of Zophobas morio XP_063913854.1 suggesting that these species may belong to the same category. The conserved domain, the secondary and three-dimensional structures of Tribolium castanueum were also predicted with iterative threading assembly refinement (I-Tasser) software. Phylogenetic analysis was carried out using Molecular Evolutionary Genetic Analysis software. The TricaPRO add to the Bank of insect protease suggest an important biocontrol applications.

This study was carried out with the aim of understanding how farmers perceive and deal with fall armyworm (FAW) infestations in maize crops. Data based on a questionnaire were collected across nine districts of the Punjab province in Pakistan. Findings revealed that about 38% of farmers had medium-sized landholdings and had been cultivating maize crop for the last 11–20 years. Hybrid maize seed was used by 55% of the farmers, and 60% of the maize grown was used as fodder, as well as a cash crop. Surprisingly, only 39% of farmers were able to correctly identify FAW; however, the majority (72%) recognized the larvae as the most damaging stage. Although most of the farmers (71%) grew maize crops during both seasons, only 34% of the farmers recognized autumn as the peak infestation period of FAW. However, despite limited awareness, a high percentage (86%) of farmers managed FAW effectively using various chemical treatments. This study also highlighted the influence of some factors on farmers’ perception of FAW such as: age, farming experience, and maize cultivation practices. Overall, the findings emphasize the need for increased awareness of the basic biology and targeted management strategies for FAW to safeguard maize crops in the region.

The melon fruit fly, Bactrocera cucurbitae, is an important insect pest responsible for significant yield losses in vegetables. Conventional control methods, like pesticide applications, have certain limitations, including environmental contamination. This study evaluated the chemosterilant potential of five new insect growth regulators (IGRs)—Pyriproxyfen; Novaluron; Lufenuron; Buprofezin; and Flubendiamide—at concentrations ranging from 50 to 300 ppm in a 5 mL diet against B. cucurbitae. Laboratory trials identified Lufenuron as the most effective IGR, which reduced fecundity by 68.4% and adult emergence by 70.97% at a 300 ppm concentration. Other IGRs, Pyriproxyfen; Novaluron; Buprofezin; and Flubendiamide, also significantly reduced fecundity and adult emergence at higher concentrations. Based on laboratory performance, Lufenuron was selected for field trials using six bait traps per 0.4 hectares. The field trials demonstrated a higher number of B. cucurbitae adult captures in Lufenuron-based bait traps compared to the control and reductions in crop damage, with fruit fly damage decreasing by 7.01% in August and 4.25% in September. This study highlights the potential of chemosterilant baited traps as a promising approach for integrated fruit fly management programs in cucurbitaceous vegetables.

Tomato leaf miner Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) has gained the status of major pest globally. Integrated pest management (IPM) consists of different control methods. This field study was conducted to evaluate the influence of different pheromone-based traps to attract the male population and the potential of sticky pads of four different colors in capturing the adults in the absence of pheromone lures. The trials were conducted in Khyber Pakhtunkhwa (Pakistan) for two consecutive years, 2020 and 2021. The Delta trap with rubber septum type lure was significantly more attractive in both years, with mean number of capturing 76.0 and 86.17, as compared to polymer wax (32.83 and 28.2) and polymer vial (10.37 and 11.77), lures. The highest mean number of capturing of T. absoluta adults were noted as 17.93 and 21.73 with black color sticky trap without pheromone, whereas the lowest number of adults, i.e., 1.33 and 1.47, were captured during the first and second year of the study, respectively, with yellow color sticky traps. However, a significant difference was found in pheromone lures and among black, red, green, and yellow color sticky pads. Hence, Delta traps equipped with rubber septum pheromones lures and black colored sticky pads were more useful for the control of T. absoluta than any other colored sticky pads and pheromone lures alone. These findings could be helpful for the integrated management of T. absoluta.

This study investigates the nematicidal efficacy of Purpureocillium lilacinum strain (AUMC 10620) combined with avermectin (B1a and B1b) against the citrus nematode Tylenchulus semipenetrans, both in vitro and in vivo. Laboratory experiments tested four concentrations of P. lilacinum (2.5, 5, 10, and 15 × 10⁷ spores/mL) mixed with 250 ppm avermectin, assessing their effects on nematode juveniles (J2) and eggs. Results showed significant increases in juvenile mortality and egg hatching inhibition with the combined treatments compared to individual applications. The highest concentration (15 × 10⁷ spores/mL + 250 ppm avermectin) achieved 100% juvenile mortality and 83.33% egg hatching inhibition after 72 h. Field trials confirmed the superior efficacy of the combined treatment, with P. lilacinum (15 × 10⁷ spores/mL) and avermectin (1000 ppm) reducing nematode populations by 70.85% in mandarin trees and 70.77% in sweet orange trees after three weeks, compared to the 83.59% and 81.76% reduction, respectively, achieved by oxamyl. These findings suggest that mixtures of P. lilacinum and avermectin can serve as effective, eco-friendly alternatives for controlling nematodes in citrus orchards.