Eurygaster integriceps (Puton)
Taxonomic placing: Insecta, Hemimetabola, Hemiptera,Heteroptera, Scutelleridae.
Common name: Sunn pest, a name that refers to a complex of Hemipteran bugs, of which the dominant species is Eurygaster integriceps.
Morphology: The adult, which is 11-13 mm long, is grayish-yellow to black. Such color polymorphism may be due to genetic variability or in response to environmental conditions. The male has ten spiracles, its last abdominal segment is larger than in that of the female, which has 12 spiracles and is larger than the male.
Geographical distribution: Eurygaster integriceps occurs throughout the Mediterranean basin, in North Africa, and the northern regions of the Middle East, which include Turkey, Syria, Lebanon and Jordan. (CIE Map Series A #40).
Host plants: Wheat, barley and other cultivated or wild species of graminaceous plants.
Life cycle: The adult bug undergoes seasonable adult diapause in the winter after migrating to mountain sites. Diapause terminates in the spring and the pest returns to areas with cereal crops, where field populations gradually increase due to continued invasions. Females oviposit in clusters of 5-15 eggs, mostly on the undersides of smooth leaves. The sex ratio may vary between different cohorts, depending on environmental conditions during embryonic development. High temperatures and humidities promote pest outbreaks whereas harsh winters adversely affect adults in diapause, decreasing the extent of pest outbreaks.
Economic importance: The Sunn pest is a serious pest of graminaceous crops like wheat and barley. In central and western Asia it accounts for annual barley losses of 20-30% and up to 100% losses for wheat, its main host. An entire crop may be destroyed in the absence of control measures. Subsequent damage to surviving, developing cereal seed kernels may result in “white ears”, and in reductions of seed weight and germination rates. In addition, the baking quality of the flour can be adversely affected by the degradation of the wheat. In the Middle East the sunn pest complex is composed of other bugs that accompany E. integriceps. Their numbers vary from year to year, a significant attack occurring about once in seven years, causing yield losses worth tens of millions of dollars.
Management
Horticultural methods: The early application of fertilizers on winter crops, the early sowing of spring crops, and the autumnal ploughing of crop residues.
Plant resistance: Selecting wheat varieties that are resistant to the pest and/or varieties that ripen early and can be harvested early. Varieties with a strong gluten index have some tolerance to the pest.
Chemical control: If necessary, the optimal time to apply chemicals (such as organophosphates or pyrethroids is when 40% of the immature pest population consists of second-instar larvae. IGRs prevent the emergence of adults and decreases their damage. However, pest populations frequently remain low enough so that spraying is unnecessary.
Biological control: Several generalist spiders and predatory beetles prey on the pest. A tachinid fly attackes the late instar nymphs and adults, castrating them. In some parts of Turkey hymenopterous egg parasitoids of the genus Trissolcus effectively control the pest. When only small populations of the first-generation adults occur and when at least 40% of first instar larvae, 50% of second instar or 70% of third are parasitized, chemical control is unnecessary. Entomopathogenic nematodes and various isolates of entompathogenic fungi also infect and kill the pests.
References
Amir-Maafi, M. and Parker, B.L. 2011. Biological parameters of the egg parasitoid Trissolcus grandis (Hym.: Scelionidae) on Eurygaster integriceps (Hem.: Scutelleridae). Journal of Entomological Society of Iran 30: 67-81.
Bandani, A.R., Alizadeh, M. and Talebi, K. 2005. Toxicity of fenitrothion, an organophosphorus pesticide, against summer population of Sunn pest, Eurygaster integriceps Put. (Hemiptera: Scutelleridae). Communications in Agricultural and Applied Biological Sciences. 70: 775-777.
Canhilal, R. Reid, W., Kutuk, H. and El-Bouhssini, M. 2008. Susceptibility of Sunn pest, Eurygaster integriceps Puton (Hemiptera: Scutelleridae), to various entomopathogenic nematodes (Rhabditida: Steinernematidae and Heterorhabditidae). Journal of Agricultural and Urban Entomology 24: 19–26.
Critchley, B.R. 1998. Literature review of Sunn pest Eurygaster integriceps Put. (Hemiptera, Scutelleridae). Crop Protection 17: 271–287.
Kostyukovsky, M. (and 7 co-authors) 2010. Management of Sunn pest for better wheat quality and stable profitability. Israel Agriculture 2010.
Malipatil, M. 2015. Diagnostic methods for Sunn pest Eurygaster integriceps. Eurygaster integriceps . At http://www.padil.gov.au/pbt.
Mojaver, M. and Bandani, A. R. 2010. Effects of the insect growth regulator pyriproxyfen on immature stages of Sunn Pest, Eurygaster integriceps Puton (Heteroptera: Scutelleridae). Munis Entomology & Zoology 5: 187-197.
Parker, B.L., Skinner, M., Costa, S.D., Gouli, S., Reid, W. and El Bouhssini, M. 2003. Entomopathogenic fungi of Eurygaster integriceps Puton (Hemiptera: Scutelleridae): collection and characterization for development. Biological Control 27: 260-272.