Molecular Entomology 2024, Vol.15, No.5, 179-191 http://emtoscipublisher.com/index.php/me 182 indica), one of the most commonly used botanical biopesticides, contains compounds like azadirachtin that disrupt the hormonal balance of insects, affecting their feeding behavior, reproduction, and molting. These compounds act as growth regulators, preventing the pest from completing its life cycle and eventually leading to death (Lengai and Muthomi, 2018). Another effective botanical pesticide is pyrethrum, which acts on the nervous system of insects, leading to paralysis and death. Pyrethrum binds to sodium channels in nerve cells, keeping them open longer than normal, which disrupts nerve signaling and eventually kills the pest (Reddy and Chowdary, 2021). This makes it a fast-acting insecticide that is used widely in IPM programs for maize and other crops. Furthermore, plant-derived essential oils such as those from eucalyptus or citronella function as repellents, masking the odor cues that pests use to locate their host plants. These oils affect the sensory receptors of insects, making it difficult for them to feed or reproduce, thereby reducing pest populations over time (Parajuli et al., 2022). 2.3 Biochemical biopesticides and disruption of pest behavior Biochemical biopesticides, including pheromones, function primarily by disrupting the behavior of insect pests. Pheromones are used in traps or are released in fields to confuse male insects, making it difficult for them to locate females and mate, effectively reducing the population over time. For example, pheromone traps are widely used in maize fields to control the European corn borer by interfering with the insect's reproductive cycle (Nazir et al., 2019). Another mechanism involves the use of kairomones, which attract natural enemies of pests to crops, enhancing biological control efforts. These chemical signals can lure parasitoids or predators that naturally feed on pest species, helping to keep pest populations in check without the need for chemical pesticides. This is particularly effective when used in conjunction with other IPM methods, such as microbial or botanical biopesticides (Reddy and Chowdary, 2021). In addition, certain biochemical pesticides act as Insect Growth Regulators (IGRs), which interfere with the normal development of insect pests, preventing them from reaching adulthood and reproducing. These compounds disrupt hormonal pathways, such as juvenile hormone regulation, which is crucial for insect growth and molting, effectively controlling pest populations by limiting their reproductive capabilities (Kumar et al., 2021). 2.4 Synergistic effects with other IPM methods Biopesticides are often used in combination with other IPM methods to enhance their effectiveness. For example, microbial biopesticides can be used alongside botanical pesticides to create a synergistic effect. This combination can target multiple stages of the pest's life cycle, increasing the overall efficacy of the pest management strategy. Research has shown that combining Metarhizium fungi with neem products can significantly reduce pest populations, as neem weakens the pest's immune system, making them more susceptible to microbial infection (Reddy and Chowdary, 2021). Additionally, the integration of biopesticides with cultural control methods, such as crop rotation or intercropping, helps to disrupt pest habitat and reduce pest pressure. The combined approach not only minimizes pest outbreaks but also improves the sustainability of the pest management program by reducing reliance on chemical pesticides (Singh et al., 2019). Finally, combining biopesticides with precision agriculture technologies, such as drone-based pest monitoring, can optimize the application of biopesticides, ensuring that they are applied in the right amounts at the right time. This integration helps reduce the overall cost of pest management while increasing the precision and effectiveness of control measures (Nephali et al., 2021). 3 Benefits of Biopesticides in IPM 3.1 Environmental benefits and reduced chemical use Biopesticides provide a sustainable alternative to synthetic chemical pesticides, which have been associated with
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