Banker plant systems are a biological control method that pairs secondary plants to main crops. The secondary plants support parasite (or predator) colonies that have either been reared or brought in on the secondary plants. Thus, banker plant systems play an active and dynamic role in mediating the interaction between herbivorous insects and their natural enemies (Paré and Tumlinson, 1997). In fact, the addition of secondary plants to crops is a promising method for pest management (Parolin et al., 2012), as the dissimilarity of the banker plants in comparison to the main crops ensures that the parasites have more pests to feed on, which results in them remaining in the field longer.
Plants release volatile compounds as a response to pests feeding on them. These chemical signals attract the natural enemies (parasites or predators) of these pests and operate in several agricultural species, including cotton (Gossypium hirsufum L.; McCall et al., 1993, 1994; Loughrin et al., 1995), corn (Zea mays L.; Turlings et al., 2000), and okra (Abelmoschus esculentus). The moment that a parasitoid has located a host larva, it injects its eggs into the host, which shortens the feeding life of the host and terminates its reproductive cycle so that the parasitoid (or predator) can propagate (Tumlinson et al., 1993; Turlings et al., 1993). Although the connection between damage-released plant volatiles and the attraction of the parasites or predators of herbivorous insects has been demonstrated in diverse conditions, the sequence of plant biochemical reactions that trigger volatile release as a response to pest feeding is not yet well understood (Paré and Tumlinson, 1996).
Banker plants are a biological control method that can sustain the management of common pests used in crop production (Kuo-Sell, 1987; Jacobson and Croft, 1998; Schoen et al., 2000). These systems consist of arthropod natural enemies (i.e., predators and/or parasitoids), alternative prey or hosts for the natural enemies, and plants (banker plants) that support the alternative prey or host (Huang et al., 2011). Banker plants increase the effect of biological control conservation strategies (Parella and Lewis, 2017; Frank, 2010; Huang et al., 2011) by providing an optimal habitat for the natural enemies of pests, thus promoting its survival, longevity, and reproduction by providing food and shelter (Arnó et al., 2000; Gurr et al., 2000; Huang et al., 2011). Banker plants that do not require a large production space and that can easily conform to good agricultural practices are preferred. In addition, banker plants can help avoid the need for pesticide sprays (Frank, 2010).
Recent studies reviewed the use of secondary plants in crops and the area surrounding crops and highlighted their most important functional characteristics to improve pest management (Parolin et al., 2012a, b
Pests can be added to the list of anticipated negative effects of climate change, with increased floods, droughts, and wildfires. Longer growing seasons and a warmer climate allow weeds and insect pests to proliferate, which will most likely lead to increased pesticide use, which further increases the harmful emissions that further exacerbate climate change. This cycle could potentially be broken by embracing regenerative methods (e.g., banker plant system) in agricultural pest control that could reduce pesticide use.
The report from the Intergovernmental Panel on Climate Change found that about 30% of global emissions leading to climate change are attributable to agricultural activities, including pesticide use Californians for Pesticide Reform (CPR). More than 200 million pounds of agricultural pesticide active ingredients are applied to California fields each year, of which more than 40 million pounds are fumigants, which are among the most hazardous and greenhouse gas-producing pesticides (CPR).Fumigant use has been shown to contribute to nitrous oxide, a greenhouse gas 300 times more potent than carbon dioxide (IAASTD, 2009). Koleva et al. (2010) found that climate change likely increases the toxicity risk to aquatic species by 47% due to the increased application of agricultural pesticides, with more than 90% of climate change in the aquatic environment induced by impacts of pesticide pollution.
Countries around the world are now recognizing the unique role that agriculture can play in sequestering carbon. Nearly the entire European Union has joined a host of nations in signing the international initiative “4 per 1000” in the Lima-Paris Action Agenda, which is officially recognized by the Paris Climate Accord. The initiative recognizes that a 4% annual growth rate of soil carbon stock would make it possible to stop the present increase in atmospheric CO2. The participating countries are called on to achieve this goal by scaling up their regenerative farming, grazing, and land-use practices with a focus on soil health.
Increased awareness of the importance of biological control as an alternative to chemical control in crop production is needed (Bompard et al., 2013; Desneux et al., 2010; Kleespies et al., 2013; Ragsdal et al., 2011; Zappala et al., 2012). Alternative methods safer for the environment than traditional pest control methods are required, since traditional methods further exacerbate climate change. Thus, this study effectively contributes to reducing environmental pollution from the harmful emissions caused by pesticides; thereby, indirectly reducing global warming and climate change.