Maize, also called corn in some countries, is very importance animal feed and human food in some regions. It's also used as material to produce bio-fuel ethanol. Starch from maize can also be made into plastics, fabrics, adhesives, and many other chemical products. Due to its wide uses and consumptions, maize always stands as top 3 staple cereals in the world.

Maize is susceptible to many insects and diseases.

Insects:

African armyworm (Spodoptera exempta)

Common armyworm (Pseudaletia unipuncta)

Common earwig (Forficula auricularia)

Corn delphacid (Peregrinus maidis)

Corn leaf aphid (Rhopalosiphum maidis)

Corn rootworms (Diabrotica  spp) including Western corn rootworm (Diabrotica virgifera virgifera LeConte), Northern corn rootworm (D. barberi) and Southern corn rootworm (D. undecimpunctata howardi)

Corn silkfly (Euxesta stigmatis)

European corn borer (Ostrinia nubilalis) (ECB)

Fall armyworm (Spodoptera frugiperda)

Corn earworm/Cotton bollworm (Helicoverpa armigera)

Lesser cornstalk borer (Elasmopalpus lignosellus)

Maize weevil (Sitophilus zeamais)

Northern armyworm, Oriental armyworm or Rice ear-cutting caterpillar (Mythimna separata)

Southwestern corn borer (Diatraea grandiosella)

Stalk borer (Papaipema nebris)

Diseases

Rust

Corn smut or common smut (Ustilago maydis)

Northern corn leaf blight (Purdue Extension site) (Pioneer site)

Southern corn leaf blight

Maize dwarf mosaic virus

Maize streak virus

Stewart's Wilt (Pantoea stewartii)

Goss's Wilt (Clavibacter michiganensis)

Grey leaf spot

Mal de Rio Cuarto virus (MRCV)

Stalk rot

Ear rot