Insects

The first species of herbivore to colonize the plant can obtain advantages and displace other organisms to less favorable substrates. This study evaluated whether the colonization order of the herbivores Tetranychus ludeni Zacher and T. urticae Koch (Tetranychidae) influences their population dynamics and antioxidant enzymatic activity of bean plants (Phaseoulus vulgaris L.). Experiments manipulating the colonization priority were performed, and the activities of the enzymes ascorbate peroxidase (APX), catalase (CAT), and superoxide dismutase (SOD) were evaluated. The results indicated priority for T. urticae led to a significant reduction in T. ludeni abundance, suggesting that the order of species influences the total abundance of mites. The presence of mites affected the antioxidant enzymatic activities APX, CAT, and SOD. These findings provide important insights into the response of bean plants to herbivorous mite infestation, highlighting the role in plant defense against T. ludeni and T. urticae.

Western flower thrips (WFT; Frankliniella occidentalis (Pergande)) is a major pest of greenhouse ornamental crops in Ontario, Canada, and recent surveys indicate onion thrips (OT; Thrips tabaci Lindeman) is becoming increasingly prevalent. This study investigates primary routes of entry for WFT and OT in the Niagara region of Ontario. Imported plant material (chrysanthemum cuttings) was sampled from 2016 to 2019 to confirm thrips presence and species identity. Entry from outside was evaluated from June to November in 2019 at three commercial greenhouses that produced chrysanthemums year-round with a mix of vegetative, budding, and flowering plants present. Sticky cards were mounted inside and outside from June to November, and plant taps were conducted bi-weekly to evaluate thrips establishment in the crop. Cuttings consistently harboured thrips, averaging 0.04 thrips per cutting. In 2019, all but one adult specimen collected on cuttings were WFT, confirming this is an important route of entry for WFT. Onion thrips were not found on cuttings but was prevalent on cards both outside and inside greenhouses. More OT was caught on outside cards and a significant correlation between inside and outside cards (Efron’s pseudo-R² = 0.64) indicates outside populations are a likely source of OT. Additionally, eastern flower thrips (EFT; Frankliniella tritici Fitch) was abundant on cards, but uncommon in the crop. Indoor cards were poor indicators of species composition within the crop, significantly underrepresenting WFT by 71% and overrepresenting EFT by 246%, compared to plant taps. These findings support the use of cutting dips for imported cuttings, in addition to physical control measures to reduce infestation from outdoor populations. This study also highlights the importance of plant inspections for gathering accurate data when making pest management decisions as sticky cards alone may not reliably reflect thrips populations.

This study aimed to biosynthesize silver nanoparticles (AgNPs) using aqueous leaf extract of Galega officinalis and to evaluate their insecticidal activity against key stored-product pests. AgNP formation was confirmed through UV–vis spectroscopy, which showed a surface plasmon resonance peak at 380 nm. FTIR analysis indicated the presence of plant-derived functional groups likely involved in the reduction and stabilization of Ag⁺ ions. Dynamic light scattering revealed an average hydrodynamic diameter of 25.07 nm, a PDI of 0.39, and a zeta potential of −22 mV, while TEM images showed predominantly spherical and polydisperse particles ranging from 4.3 to 42.4 nm. Insecticidal bioassays performed on Sitophilus granarius, Tribolium confusum, Plodia interpunctella, and Ephestia kuehniella revealed concentration-dependent mortality. The highest mortality rates were recorded at 1000 ppm, reaching 100% in T. confusum, 83.33% in P. interpunctella, and 76.67% in both S. granarius and E. kuehniella. These findings demonstrate the potent insecticidal activity of G. officinalis-mediated AgNPs and support their potential as environmentally friendly alternatives for stored-product pest management, warranting further studies on safety, large-scale synthesis, and integration into pest-control programs.