**2. The cultivation of maize in Mexico**

Maize (*Zea mays*) is native to Mexico, and from the evidence found in Tehuacan, Puebla, it is known that its cultivation began seven thousand years ago. Its domestication allowed the nomadic groups to become sedentary, thus becoming the livelihood of the Mesoamerican peoples.

In Mexico, corn is part of the daily diet, it is the crop with the greatest presence in the country, and it constitutes an input for livestock and for obtaining numerous industrial products, therefore, from the food, economic, political, and social, it is the most important agricultural crop [14].

Mexico is the center of origin of maize. Here, most likely, the greatest diversity of maize in the world is concentrated and here its wild relatives, the teocintles, and another set of related grasses, species of the genus *Tripsacum* (maicillos) have evolved and live [15].

Its production is divided into white and yellow maize; white corn is mainly for human consumption, while yellow corn production is for industry or the manufacture of balanced feed for livestock production.

*Genetic Delimitation of Fall Armyworm Parasitoids Isolated in Maize in Durango, Mexico DOI: http://dx.doi.org/10.5772/intechopen.112612*

Corn is the most widely produced maize in the world [4, 16]; the most important countries in terms of planting area in the 2021 agricultural cycle were: China, with an area of 42 million hectares and a production of 273 million tons, followed by the United States and Brazil, with an area of planting of 34.43 and 20.8 million ha and production of 382.6 and 118 million tons, respectively; Mexico ranked sixth in terms of planting area with 7.3 million ha and eighth in terms of production with 28.00 million ha. tons [17]; in Mexico, the main maize-producing states are: Sinaloa, Jalisco, State of Mexico, Guanajuato, and Michoacan [18].

#### **2.1 Main maize pests in Mexico**

The primary pests that attack maize are fall armyworm *Spodoptera frugiperda* (FAW), corn earworm *Heliothis zea* (Boddie), blind hen *Phyllophaga* sp., thrips *Frankliniella* sp./*Thrips tabaci* Lindeman [4], maize leafhopper *Dalbulus maidis* (Delong & Wolcott), corn weevil *Geraeus senilis, and* Gyllenhal and *Nicentrites testaceipes* (Champion). The genera and species that appear depend on the region, climatic conditions, and planting season (spring–summer) (winter–spring). Although generally, pests are specific to their host.

#### **2.2 Fall armyworm**

The fall armyworm (FAW) (*Spodoptera frugiperda*) has been a consistently important insect pest for several crop species, especially maize, in America for centuries. FAW prefers maize, but it is also common on sorghum and rice and is sporadically important on a vast array of additional crops and plants, including cotton and vegetables [19].

FAW has high fecundity, can rapidly develop resistance to insecticides, and has the capacity to migrate long distances, characteristics which have allowed it to rapidly disperse and establish in different regions (America, Australia, Africa, Asia, E.U. Oceania, Nepal, over 70 countries) [20–22].

#### **2.3 Biological control**

Biological control is a component of an integrated pest management strategy. It is defined as the reduction of pest populations by natural enemies, using natural enemies such as parasitoids, predators, pathogens, antagonists, or competitors to suppress pest populations [19].

Biological weed control includes insects and pathogens. Biological control agents for plant diseases are often referred to as antagonists. Parasitoids are species whose immature stage develops on or within a single insect host, ultimately killing the host. Many species of wasps and some flies are parasitoids. Pathogens are disease-causing organisms, including bacteria, fungi, and viruses. They kill or debilitate their host and are relatively specific to certain insect groups [23].

**Parasite.** It is an organism that lives at the expense of another organism.

**205 Parasitoid.** The insect in its immature stage acts as a parasite; when they are adults, they usually fly; parasitoids can kill their host in this case the armyworm. Parasitoids are natural enemies, which are widely used in biological control programs because when an arthropod is parasitized, the female parasitoid inserts its eggs with the help of an ovipositor inside the body of the host or attaches them outside of it, and instead of as long as the pest insect (in this case) continues to develop, it dies and the parasitoid(s) (Diptera and/or Hymenoptera) emerge from its body. The main types of insects that act as parasitoids are wasps, flies, some beetles, mantis flies, and twisted-wing parasites [24].
