Field Crop 2025, Vol.8, No.6, 274-283 http://cropscipublisher.com/index.php/fc 278 Meanwhile, the activity of the soil has increased, and the resilience of the ecosystem is also recovering. Ultimately, diversification has brought the cotton fields back to life. Not only have there been fewer pests, but the system itself has also become more stable and better at adapting to changes. 4.3 Interactions with other pest control strategies Companion cultivation itself is not a "panacea". It is very difficult to completely solve the pest problem in cotton fields by relying on it alone. The real effect often emerges when it is combined with other prevention and control measures. For instance, in an integrated pest management (IPM) system, companion plants are often used in conjunction with biological control agents and selective pesticides, forming a complementary relationship. Some companion plants can attract natural enemies, making biological control more effective. Some have reduced the dependence of pests on a single population through diversified planting structures (Quan and Wu, 2023; Razzaq et al., 2023). In genetically modified cotton systems, farmers sometimes interplant non-genetically modified crops as "refuge zones", which can slow down the emergence of pest resistance. There are exceptions. In some areas where the climate or the types of pests are special, the control effect of co-planting is not obvious. Overall, it is more like a part of a complete management plan and needs to be coordinated with other strategies to maintain ecological balance and stable yields while controlling pests. 5 Case Study: Field Applications of Biocontrol and Companion Planting 5.1 India: community-based biological control programs In India, pest control is no longer as simple as spraying pesticides. In many places, the power of "people" has begun to be relied on. Integrated Pest management (IPM) projects involving farmers, communities and technicians have become a new way to control cotton bollworms and whiteflies. Some areas in the north are typical examples. Farmers do not merely rely on pesticides but have learned to monitor the number of pests, select cotton varieties with stronger resistance, decide whether to intervene based on economic thresholds, and combine it with the precise application of biopesticides (Kumar et al., 2020). The result was unexpected: the amount of pesticide used decreased significantly, but the output increased instead. Each hectare can save two to three thousand rupees. Even in the year when whiteflies broke out, the output of cotton down set a record. Similar experiences have also been replicated in Karnataka, where pheromone traps have been employed. Coupled with farmer training and timely intervention, the control effect has become more stable. With less input and less environmental burden, farmers' confidence has also significantly increased (Shreevani et al., 2024). 5.2 Africa: intercropping cotton with cowpea and maize In Africa, farmers tend to deal with pests in a simple way by intercropping. Cotton, cowpeas and corn are planted in the same field. It seems messy, but in fact, there is a pattern. Researchers found in Zambia and Cameroon that such combinations could significantly reduce the number of pests, especially cotton bollworms and aphids. The number of aphids even decreased by more than 40% (Farsia Djidjonri et al., 2021; Silberg et al., 2024). Meanwhile, the number of natural enemies such as predatory beetles is increasing, the cotton bolls are developing more fully and the yield is more stable. Some statistics have shown that intercropping can increase the yield by an average of about 23%, and farmers' income also grows accordingly. Of course, this is not the same everywhere. The effects vary greatly due to differences in climate, soil conditions and management levels. It is worth mentioning that in some areas, intercropping of corn and cowpeas is no longer merely a pest control measure; it is regarded as a long-term strategy that balances yield and ecology. 5.3 Australia: combining Beauveria bassiana with pigeon pea rows There are actually not many local studies on this aspect in Australia, but from the experiences of other regions, some practices worth learning from can still be found. Some people attempted to combine Beauveria bassiana with associated crops, and the results were quite satisfactory (Figure 2) (Mantzoukas et al., 2023). This fungus itself is a "natural enemy" of pests, capable of infecting insects such as lepidoptera larvae and rendering them inactive within a short period of time. If cardamom is planted simultaneously in cotton fields, the activity space of natural enemies will increase, and the number of pests will also decrease accordingly (Papantzikos et al., 2024). Although it seems to be just a simple combination, it has brought about a chain reaction, reducing the reliance on
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