Kingdom: Animalia
Phylum: Arthropoda
Subphylum: Hexapoda
Class: Insecta
Infraclass: Neoptera
Subclass: Pterygota
Order: Diptera
Suborder: Brachycera
Infraorder: Acalyptratae
Superfamily: Carnoidea
Family: Chloropidae
Subfamily: Chloropinae
Genus: Meromyza
Subject: Meromyza americana Fitch, 1856

The adults are yellowish-white flies about 1/5 inch long, with three conspicuous black stripes on the thorax and abdomen and with conspicuous bright-green eyes. The larvae are greenish maggots about 1/4 inch in length.

Host Range
Wheat stem maggots attack cereal crops, including wheat, rye, barley, and oats. Other hosts include bluegrass, millet, timothy, and a range of other native and introduced grass species. Corn is some times damaged when planted into infested cereal crop residue that has been grazed or sprayed out in early spring.

Wheat stem maggot larvae tunnel into the upper portions of the wheat stem just above the upper node, resulting in the severing of stems at this point. Subsequently, the wheat head will die and turn white. The appearance of these damaged heads is dramatic, and infestations of only one to two percent will be very apparent. Damage from this insect in some years is much more apparent than in other years, but the reasons for this are not known. In most years, damage is limited to less than one to two percent infested stems. Damage is more likely to occur in field margins next to wild grasses where the insect will be present. Wheat stem maggot populations may increase in no-till situations because larvae survive better in the undisturbed stems; however, the fly population is probably limited by its survival in host grasses during the mid-summer generation when wheat is not present.

The use of delayed planting, following the dates recommended to escape Hessian fly infestations, is an effective management practice. Destruction of volunteer plants is also recommended. The effectiveness of chemical control is unknown. Currently, we do not have the knowledge to time such applications properly. Fortunately, damage rarely exceeds 1 to 2 percent of the heads and is usually considered inconsequential.
https://entomology.k-state.edu/extension/crop-protection/wheat/wheat-stem-maggot.html

https://bioone.org/journals/journal-of-the-kansas-entomological-society/volume-81/issue-3/JKES-709.12.1/Occurrence-of-the-Wheat-Stem-Maggot-Meromyza-americana-Fitch-Diptera/10.2317/JKES-709.12.1.short

https://www.cabidigitallibrary.org/doi/10.1079/cabicompendium.33465

There are few options available for managing the wheat stem maggot. No-till production practices may increase damage potential, but rotations that include non-host (non-grass) crops will reduce the potential for the buildup of wheat stem maggot populations. Also, control of volunteer wheat eliminates this host for insect buildup. Where practical, planting after the Hessian fly ‘fly-free’ dates will also reduce damage potential by avoiding the fly activity period in the early fall. Insecticidal control is impractical because of the difficulty in determining the optimum timing for control