**4. New sources of resistance**

**•** Use the postharvest management: use the association of herbicides with different modes of

**•** Monitor the results of the implemented management strategy, preventing the establishment

**•** Use the best agronomic practices to maximize crop competitiveness with weeds, also

Regarding the management of volunteer plants after the maize crop, it is common the

The amount and timing of germination of these maize kernels, producing crop residues (also known as "tigueras"), depends on many factors, being the quality of the previous harvest one of the most important; herbicides called graminicides are the main management tool of these plants. Volunteer plants are controlled until the V3/V4 stage to obtain consistent and quick controls. Weed competition is prevented with subsequent soybean crop, making the early

Seed treatment (ST) is a practice that seeks control of underground and initial culture pests, a period of great susceptibility to pests. The damage caused by these pests results in crop failures due to the attack on the seeds after planting, damage to roots after germination, and shoots of newly emerged plants. The correct choice of chemical is essential to the success of this operation. We recommend using products from broad spectrum to provide efficient control of the initial pests of the crop complex, which will bring results as the protection of plants in the initial development phase, broad-spectrum pest control, and maintenance of the initial

Crop rotation consists of alternating the planting of different species of crops in the same agricultural area. The choice of species for crop rotation should take into account economic

To obtain maximum efficiency, improving productivity capacity of the soil, the planning of crop rotation must consider, preferably commercial plants and, whenever possible, involving species that produce large amounts of biomass and rapid development, cultivated singly or

Among the benefits of crop rotation in pest management in *Bt* maize, the highlights are as follows: improved physical and chemical properties of the soil, reduction of disease inoculum source for subsequent crops, reduction of the initial population of some insect pests of the crop, aid in weed management, and ability to switch herbicides for the control and increase in the

occurrence of germinação of remaining grains from previous crop spontaneously;

action.

74 Insecticides Resistance

of remnant populations of weed in the crop.

management of volunteer plants.

**3.4. Seed treatment**

stand of the crop.

**3.5. Crop rotation**

system productivity.

avoiding seed dispersal by agricultural implements.

factors, pests, diseases, and fertilization, among others.

intercropped with commercial crops.

The interaction of plant-herbivore insects occurs in various combinations of genotypes and environments, which makes its coevolution process broad and diverse. For this reason, plants and insects can provide a wide range of mechanisms, which make them resistant to attack or able to circumvent the acquired resistance. Thus, when considering the coevolution as a dynamic process, we must be sure that the natural resistance or artificially acquired by an organism may be short-lived or long-lasting, but difficultly can occur permanently. On the other hand, the duration of plant resistance will be greater as lower the speed on the evolution of resistance in the insect target, in other words, we must focus on strategies to reduce the selection pressure on the target. It is precisely in this aspect that the search for new genes that may confer resistance to insects fits. For example, using more than one resistance gene in a genetically modified plant, it is possible to prolong the emergence of resistant individuals, especially if these genes relate to different sources of resistance as a toxin and a compound that attracts a natural enemy target.

The prospect of important genes in plant–insect interaction has the fundamental objective of assisting in the preparation of new alternatives, both with the identification of genes that make plants resistant or susceptible to insect attack, as with the identification of genes that are associated with the insect's ability on circumvent the defenses of their hosts. Knowledge of the physiology of insects resistant to *Bt* toxins, for example, is important to the discovery of new targets (genes or genetic polymorphisms).

Otherwise, other *Bt* toxin proteins or other natural enemies of herbivorous insects may also represent new alternatives resistance.

In this sense, studies aiming at prospecting for new important genes in plant-herbivore insect interactions can concentrate on the plant by identifying mRNA expressed (transcriptome) [31], proteins (proteomics) [32], or metabolites (metabolomics) synthesized in specific tissues and moments of the interaction, or they may focus on the insect by the use of the same tools applied to tissues or moments fundamental to the success of interaction, such as the study of the digestive proteins secreted in the midgut and that enable herbivores [31] or the study of regulatory elements of metamorphosis [34]. Alternatively, prospecting studies can focus on the interaction of model organisms for which there is already high amount of generated knowledge (genomic knowledge and tools to produce genetic alterations), such as *Arabidop‐ sis*–*Scaptomyza flava* interaction (*Drosophila*) [35], or may focus on a single study or specific response mechanism by, for example, the application of a compound that is known to cause a direct defense response in plants [36].

Different strategies can be useful for gene prospecting, including comparative analyzes of transcriptoma, proteomics, metabolomics, and the functional study of genes by mutagenesis, overexpression, and gene silencing. Indeed, comparative analyzes can be exploited as ideal strategies for global exploration of important genes in plant–insect interaction. Such analyzes can be conducted in order to compare important genes in plant–insect interaction in different environmental conditions [37] in resistant and susceptible plants [38] in injured plants by different insects [39] and others.

Global prospection strategies achieved particular prominence with the use of new technologies of DNA sequencing to characterize transcriptoma (RNA-seq). With RNA-seq strategies, it is possible to generate billion bases of information in single runs (at a much lower cost than Sanger sequencing), which allows access to regulatory genes, represented by one or a few mRNAs [40] and covering full-length cDNAs [41].

Although the global strategies of gene prospecting are potentially unlimited, the success of identifying real candidates depends on the development of an efficient experimental design. On the work of Li et al. [37], the defense mechanisms of two soybean varieties, that is, resistant and susceptible to an aphid, were studied using microarrangements of cDNA, and the collection period after an infection determined by the time necessary to the insect reaches the xylem vessel elements in the plant, about 8 hours in the resistant cultivar and 3.5 hours in the susceptible cultivar.

The large-scale study of metabolites produced by plants in the presence of insect pests also consists in an innovative possibility of seeking alternatives for its control and the identification of genes or important metabolic pathways. In soybean leaves [42], it was observed that constitutively leave extracts of PI 227687 contain the isoflavonoid genistein and seven flavonol glycosides, including rutin [43], by studying the leaf extract resistant to insect genotypes PI 274454, "IAC-100," and PI 229358, which identified and quantified the flavonol rutin and the isoflavonoid genistein.

Their identification and their role in the interactions of insects with soybean plants can guide geneticists in order to keep them in descendant generations as part of the defense armory of plants against herbivores. To study if the insect resistance of genotypes PI 227687, PI 274454, and "IAC 100" is due to chemicals present in their constitution, they used extracts of these genotypes mixed to artificial diet. By the results obtained, Piubelli et al. [43, 44] found that those strata negatively affect the biology of *Anticarsia gemmatalis*. Additionally, studies have shown that the flavonol rutin causes antibiosis in *Trichoplusia ni* (Hübner) [45, 46].

In general, although the *Bt* strategy to control lepidopteran still is the world's most important in controlling pests, new sources of resistance may operate independently or may also be added to the *Bt* strategy so as to promote their own maintenance of *Bt* resistance in commer‐ cialized transgenic plants.

Molecular biology tools have supplemented the information generated by morphological and behavior studies, contributing to the elucidation of issues in the fields of taxonomy, ecology, pests population genetics, parasitoids, predators, and entomopathogenic bacteria. Its resolving power has allowed increased knowledge on the occurrence of cryptic species, differentiation of insect races, and separation of microorganisms species indistinguishable by morphological characters. These tools also have wide application in genetic studies of resistance to insecticides and toxins and in the determination of genes associated with these phenomena. On the other hand, they have facilitated the breeding works to plant resistance to insects, as well as the transformation of the beneficial organisms to increase pest control potential. Considering its potential and reducing reagent costs and simplifying processes, we expect a growing appli‐ cation in basic and applied fields of entomology and its related areas.
