Hessian fly | |
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Scientific classification ![]() | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Arthropoda |
Class: | Insecta |
Order: | Diptera |
Family: | Cecidomyiidae |
Genus: | Mayetiola |
Species: | M. destructor |
Binomial name | |
Mayetiola destructor (Say, 1817) | |
Synonyms | |
Cecidomyia destructor Say, 1817 |
The Hessian fly or barley midge, Mayetiola destructor, is a species of fly that is a significant pest of cereal crops including wheat, barley and rye. Though a native of Asia, upon its discovery it was believed to have been transported into North America in the straw bedding of Hessian troops during the American Revolution (1775–1783), thus the origin of its common name. However, the report of an inquiry made in 1788 by Sir Joseph Banks states that "no such insect could be found to exist in Germany or any other part of Europe". Nonetheless, it appears that this species, or one exactly like it in habits, had been known for at least a century prior to the American Revolution from a locality near Geneva, and also for a long time from some regions in France. [1]
There are usually two generations a year but may be up to five. In the spring the dark-coloured female lays about 250 to 300 reddish eggs on plants, usually where the stems are covered by leaves; the larvae feed on the sap and weaken the plants so that they cannot bear grain.
The Hessian fly was described by Thomas Say in 1817. It is a very harmful insect. It mainly attacks the stem, although if it is especially hungry it will eat any part of the plant it can find.[ citation needed ]
In 1836, a severe infestation of Hessian flies resulted in a crop shortage aggravating the financial problems of farmers prior to the Panic of 1837. [2]
M. destructor is one of the most destructive wheat pests worldwide, hence its name. [3] This has brought it much attention from wheat breeder and genetics researchers. [3] As a result the highest number of mapped R genes for resistance to insects in wheat are R genes for this pest specifically, with the unrelated Russian wheat aphid (Diuraphis noxia) also being of serious interest. [3]
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Rice is a cereal grain, and in its domesticated form is the staple food for over half of the world's human population, particularly in Asia and Africa, due to the vast amount of soil that is able to grow rice. Rice is the seed of the grass species Oryza sativa or, much less commonly, O. glaberrima. Asian rice was domesticated in China some 13,500 to 8,200 years ago, while African rice was domesticated in Africa some 3,000 years ago. Rice has become commonplace in many cultures worldwide; in 2021, 787 million tons were produced, placing it fourth after sugarcane, maize, and wheat. Only some 8% of rice is traded internationally. China, India, and Indonesia are the largest consumers of rice. A substantial amount of the rice produced in developing nations is lost after harvest through factors such as poor transport and storage. Rice yields can be reduced by pests including insects, rodents, and birds, as well as by weeds, and by diseases such as rice blast. Traditional polycultures such as rice-duck farming, and modern integrated pest management seek to control damage from pests in a sustainable way.
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Stem rust, also known as cereal rust, black rust, red rust or red dust, is caused by the fungus Puccinia graminis, which causes significant disease in cereal crops. Crop species that are affected by the disease include bread wheat, durum wheat, barley and triticale. These diseases have affected cereal farming throughout history. The annual recurrence of stem rust of wheat in North Indian plains was discovered by K.C. Mehta. Since the 1950s, wheat strains bred to be resistant to stem rust have become available. Fungicides effective against stem rust are available as well.
The Russian wheat aphid is an aphid that can cause significant losses in cereal crops. The species was introduced to the United States in 1986 and is considered an invasive species there. This aphid is pale green and up to 2 mm long. Cornicles are very short, rounded, and appear to be lacking. There is an appendage above the cauda giving the aphid the appearance of having two tails. The saliva of this aphid is toxic to the plant and causes whitish striping on cereal leaves. Feeding by this aphid will also cause the flag leaf to turn white and curl around the head causing incomplete head emergence. Its host plants are cereal grain crops including wheat and barley and to a lesser extent, wild grasses such as wheatgrasses, brome-grasses, ryegrasses and anything in the grass family.
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