Molecular Entomology 2024, Vol.15, No.5, 179-191 http://emtoscipublisher.com/index.php/me 180 produces toxins lethal to various insect pests. In maize cultivation, Bt has been used extensively to manage lepidopteran pests, particularly corn borers. When ingested by pests, the Bt toxin disrupts the midgut lining, leading to paralysis and death. The specificity of Bt makes it an ideal candidate for integrated pest management (IPM), as it targets specific pests while leaving beneficial insects unharmed (Mnif and Ghribi, 2015). Another important microbial biopesticide used in maize is Metarhizium rileyi, a fungus that infects pests like the fall armyworm (Spodoptera frugiperda). Metarhizium species are known for their ability to parasitize a wide range of insect pests, making them a powerful tool in maize IPM. Studies have shown that formulations of Metarhizium rileyi remain stable under various environmental conditions, with high efficacy in reducing pest populations. The fungus infects pests through direct contact, penetrating their exoskeleton and proliferating within, leading to death (Grijalba et al., 2018). In addition to Bacillus thuringiensis and Metarhizium rileyi, other microbial agents such as entomopathogenic nematodes and viruses are also used as biopesticides in maize cultivation. These organisms attack pest larvae or adult insects, disrupting their development and leading to reduced pest populations. The widespread adoption of microbial biopesticides in maize cultivation is driven by their low toxicity to humans and animals, as well as their ability to decompose rapidly, minimizing environmental impact (Lengai and Muthomi, 2018). 1.2 Botanical biopesticides Botanical biopesticides are derived from plant extracts and are widely used in pest management due to their natural origin and lower environmental impact compared to synthetic chemicals. Neem (Azadirachta indica) is one of the most extensively studied and used botanical pesticides in maize cultivation. Neem contains several active compounds, including azadirachtin, which acts as an insect growth regulator and feeding deterrent. It is particularly effective against pests such as aphids, leafhoppers, and corn borers. Neem-based biopesticides are safe for non-target organisms and break down quickly in the environment, making them ideal for sustainable agriculture (Lengai and Muthomi, 2018). Another well-known botanical biopesticide is pyrethrum, which is derived from the flowers of Chrysanthemum species. Pyrethrins, the active ingredients in pyrethrum, are potent insect neurotoxins that cause paralysis and death in a wide range of pests, including those affecting maize. Pyrethrum is used in maize cultivation as a contact insecticide and is favored for its rapid action against pests like the European corn borer (Ostrinia nubilalis). Its low toxicity to mammals and birds further enhances its appeal in integrated pest management strategies (Kumar et al., 2021). Botanical biopesticides are also derived from a variety of other plant sources, such as garlic, pepper, and eucalyptus. These plants contain natural compounds that repel or inhibit the growth of pests. For instance, garlic extract has been used as a repellent against insects like aphids and mites in maize fields. The use of botanical pesticides, while offering a more eco-friendly alternative to chemical pesticides, also faces challenges such as inconsistent efficacy and the need for frequent application due to rapid degradation in the environment (Parajuli et al., 2022). 1.3 Biochemical biopesticides Biochemical biopesticides include naturally occurring substances that control pests through mechanisms other than direct toxicity. Pheromones, one of the most commonly used biochemical biopesticides, play a crucial role in pest control by disrupting the mating behavior of pests. In maize cultivation, pheromone traps are used to control pests like the European corn borer (Ostrinia nubilalis) by confusing male moths and preventing them from locating females, thus reducing reproduction rates and subsequent pest infestations. This method is species-specific, minimizing harm to non-target organisms (Lengai and Muthomi, 2018). In addition to pheromones, other biochemical biopesticides include plant growth regulators and insect growth regulators (IGRs). IGRs work by interfering with the normal development of insect pests, preventing them from reaching adulthood and reproducing. In maize IPM programs, IGRs are used to manage pest populations such as
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