Sunn pest
Encyclopedia
A sunn pest is an insect belonging to a group representing several genera of the 'shield bug
' (Scutelleridae
) and 'stink bug' (Pentatomidae
) Families, with the species Eurygaster integriceps
being the most economically important. Sunn pests are found in parts of North Africa
, throughout West Asia and many of the New Independent States of Central Asia
.
The sunn pest is one of the most serious pests of wheat
and barley
in West Asia, where over $42 million (U.S.) is spent for its control. Yield loss from its damage has been estimated at 20-30% in barley and 50-90% in wheat. This insect damages these crops by feeding on leaves, stems and grains. During feeding they also inject chemicals that greatly reduce the baking quality of flour made from damaged wheat. If 2-3% of the grain is damaged, entire lots may be ruined because the flour will be unpalatable and the bread won't rise. Heavy attack causes wheat stems to break before harvest.
Large areas of wheat sometimes remain unharvested because sunn pest damage is so severe. These insects also attack barley, though damage is usually low. Large outbreaks of sunn pests generally occur every 6 to 8 years and can potentially cause yield losses of tens of millions of dollars.
Selective insecticides should only be used when pest populations reach economically damaging levels. Applications should be made when adults move into cereal fields. Research has been ongoing for decades to develop and improve management of the sunn pest. In 1997, scientists from ICARDA, the University of Vermont
, and national agricultural researchers throughout the infested region began working together to develop a model sunn pest integrated management plan.
, Syria, Kazakhstan
, Kyrgystan, Uzbekistan
and Russia
. In laboratory bioassays, they were tested against sunn pests, tarnished plant bug and western flower thrips. Several were highly pathogenic to all of these insects, and selected for further evaluation.
The next step in the development of these biological agents is to determine at what stage in the pests' life cycle fungi could best be used. Two possibilities are
Six of the most promising isolates were tested in on-plant and in-litter bioassays in January 2000. Several of the tested isolates provided 80-100% mortality within 10 days. Though sunn pest mortality occurred more rapidly among the in-litter assays, by day 15 sunn pest mortality was equally high in the on-plant assays. These results demonstrate the great potential of fungi for sunn pest IPM. It may be possible to use them both in over wintering sites and on plants in the field. Plans are underway to conduct small scale pilot tests to further evaluate their efficacy under field conditions. The compatibility of fungi with non target organisms and chemical pesticides are also planned for the future.
This work has been done in close cooperation with Dr. Mustapha El Bouhssini, Head of the Entomology Department at ICARDA. He is currently conducting research to evaluate the impact of egg parasitoids on sunn pest field populations.
Shield bug
Pentatomoidea is a superfamily of insects in the Heteroptera suborder of the Hemiptera order and, as such, share a common arrangement of sucking mouthparts...
' (Scutelleridae
Scutelleridae
Scutelleridae is a family of true bugs. They are commonly known as jewel bugs or metallic shield bugs due to their often brilliant coloration. They are also known as shield-backed bugs due to the enlargement of the last section of their thorax into a continuous shield over the abdomen and wings...
) and 'stink bug' (Pentatomidae
Pentatomidae
Pentatomidae, Greek pente meaning five and tomos meaning section, is a family of insects belonging to order hemiptera that includes some of the stink bugs and shield bugs. Their antennae are 5-segmented, which gives the family its scientific name. Their bodies are usually shield-shaped...
) Families, with the species Eurygaster integriceps
Eurygaster integriceps
Eurygaster integriceps is a species of shield bug in the family Pentatomidae, commonly known as the sunn pest or corn bug. It is native to much of northern Africa, the Balkans and western and central Asia. It is a major pest of cereal crops especially wheat, barley and oats.-Morphology and...
being the most economically important. Sunn pests are found in parts of North Africa
North Africa
North Africa or Northern Africa is the northernmost region of the African continent, linked by the Sahara to Sub-Saharan Africa. Geopolitically, the United Nations definition of Northern Africa includes eight countries or territories; Algeria, Egypt, Libya, Morocco, South Sudan, Sudan, Tunisia, and...
, throughout West Asia and many of the New Independent States of Central Asia
Central Asia
Central Asia is a core region of the Asian continent from the Caspian Sea in the west, China in the east, Afghanistan in the south, and Russia in the north...
.
The sunn pest is one of the most serious pests of wheat
Wheat
Wheat is a cereal grain, originally from the Levant region of the Near East, but now cultivated worldwide. In 2007 world production of wheat was 607 million tons, making it the third most-produced cereal after maize and rice...
and barley
Barley
Barley is a major cereal grain, a member of the grass family. It serves as a major animal fodder, as a base malt for beer and certain distilled beverages, and as a component of various health foods...
in West Asia, where over $42 million (U.S.) is spent for its control. Yield loss from its damage has been estimated at 20-30% in barley and 50-90% in wheat. This insect damages these crops by feeding on leaves, stems and grains. During feeding they also inject chemicals that greatly reduce the baking quality of flour made from damaged wheat. If 2-3% of the grain is damaged, entire lots may be ruined because the flour will be unpalatable and the bread won't rise. Heavy attack causes wheat stems to break before harvest.
Large areas of wheat sometimes remain unharvested because sunn pest damage is so severe. These insects also attack barley, though damage is usually low. Large outbreaks of sunn pests generally occur every 6 to 8 years and can potentially cause yield losses of tens of millions of dollars.
Sunn pest management
Currently, there is not a pest management strategy to control the sunn pest on a national or global scale. However, there are a number of methods that farmers can utilize to help limit the damage caused by these insects.- Monitor pest populations; sunn pest populations vary from year to year in response to climatic conditions. Pest populations should be monitored annually to determine if it is necessary to spray for the insect. Keeping records of population levels is beneficial.
- Plant early-maturing wheat varieties and harvest early; damage is less if wheat is harvested before sunn pest reach adulthood. Growing early-maturing varieties and establishing a regional uniform planting date minimizes damage. Early harvesting methods must be developed in relation to local production methods and weather conditions.
- Maintain shelter belts around wheat fields. Natural enemies reduce sunn pest populations and should be encouraged. Cereal crops should not be grown on marginal lands in the foothills. These areas should remain as uncultivated habitats where flowers and grow undisturbed, providing shelter and alternative food sources, which improve survival of these beneficial insects.
- Use chemical insecticides only if needed.
Selective insecticides should only be used when pest populations reach economically damaging levels. Applications should be made when adults move into cereal fields. Research has been ongoing for decades to develop and improve management of the sunn pest. In 1997, scientists from ICARDA, the University of Vermont
University of Vermont
The University of Vermont comprises seven undergraduate schools, an honors college, a graduate college, and a college of medicine. The Honors College does not offer its own degrees; students in the Honors College concurrently enroll in one of the university's seven undergraduate colleges or...
, and national agricultural researchers throughout the infested region began working together to develop a model sunn pest integrated management plan.
Sunn pest research
A cooperative program between the University of Vermont Entomology Research Laboratory http://www.uvm.edu/~entlab and the International Center for Agricultural Research in the Dry Areas (ICARDA), in Aleppo, Syria was initiated in 1997. Several strains of entomopathogenic fungi have been isolated from insects in their over wintering sites in TurkeyTurkey
Turkey , known officially as the Republic of Turkey , is a Eurasian country located in Western Asia and in East Thrace in Southeastern Europe...
, Syria, Kazakhstan
Kazakhstan
Kazakhstan , officially the Republic of Kazakhstan, is a transcontinental country in Central Asia and Eastern Europe. Ranked as the ninth largest country in the world, it is also the world's largest landlocked country; its territory of is greater than Western Europe...
, Kyrgystan, Uzbekistan
Uzbekistan
Uzbekistan , officially the Republic of Uzbekistan is a doubly landlocked country in Central Asia and one of the six independent Turkic states. It shares borders with Kazakhstan to the west and to the north, Kyrgyzstan and Tajikistan to the east, and Afghanistan and Turkmenistan to the south....
and Russia
Russia
Russia or , officially known as both Russia and the Russian Federation , is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects...
. In laboratory bioassays, they were tested against sunn pests, tarnished plant bug and western flower thrips. Several were highly pathogenic to all of these insects, and selected for further evaluation.
The next step in the development of these biological agents is to determine at what stage in the pests' life cycle fungi could best be used. Two possibilities are
- As they migrate to the fields in the early spring
- In their over wintering sites among the foothills surrounding the fields.
Six of the most promising isolates were tested in on-plant and in-litter bioassays in January 2000. Several of the tested isolates provided 80-100% mortality within 10 days. Though sunn pest mortality occurred more rapidly among the in-litter assays, by day 15 sunn pest mortality was equally high in the on-plant assays. These results demonstrate the great potential of fungi for sunn pest IPM. It may be possible to use them both in over wintering sites and on plants in the field. Plans are underway to conduct small scale pilot tests to further evaluate their efficacy under field conditions. The compatibility of fungi with non target organisms and chemical pesticides are also planned for the future.
This work has been done in close cooperation with Dr. Mustapha El Bouhssini, Head of the Entomology Department at ICARDA. He is currently conducting research to evaluate the impact of egg parasitoids on sunn pest field populations.