Acanthomytilus sacchari (Hall)

Taxonomic placing: Insecta, Hemimetabola, Hemiptera, Sternorrhyncha, Coccomorpha, Coccoidea, Diaspididae.

Common name: scale insect.

Distribution: Africa, Cyprus, Turkey, Iran, Hungary, Italy, Eastern Asia, Mauritius and Australia.

Morphology: Shield of female oystershell-like, brown, about 2-3 mm in length, juvenile exuvium pale-brown, located at the narrow end, male shield shorter and narrower than female cover, similar color. Body of female white, elongate. Four or five two-barred macroducts present on each side of pygidium, which also bears 2 definite pairs of lobes, third and fourth lobes minute. Perivulvar pores in 5 clusters, about 25 pores all together.

Host plants: Several Poaceae, including Arundo donax (L.), Imperata cylindrical (L.) P.Beauv., Phragmites australis (Cav.) Trin ex Steud, Saccharum officinarum (L.), Sorghum halepense (L.) Pers., as well as Dasylirion sp. (Asparagaceae).

Life history: This scale raises 4 annual generations between late May and mid-December. It appeas on sugarcane in early May, settling on stems under leaf sheaths and on the leaves, and sometimes colonizing the rhizomes. Average generation time was 30 days at a mean temperature of 29.0°C., a female producing about 50 progeny.

Economic importance: Acanthomytilus sacchari is an importance pest of sugar cane in Egypt.

Management

Monitoring: Pulling back sugarcane leaf sheaths (or other susceptible grasses) and searching for the brown scale covers on the exposed stems.

Biological control: The encyrtid Metaphycus flavus is an important endoparasitoid of A. sacchari, causing close to 30% mortality. Several Aphelinidae also attack the pest.

References

Doĝanlar, M.A., Yiĝit ,Y., Ben-Dov Y., Űremiş I. and Arslan, M. 2010. Preliminary studies on two Diaspididae (Hemiptera) species feeding on Johnsongrass (Sorghum halepense) in Turkey. Phytoparasitica 38: 231–236.

Watson, G.W. and El-Serwy, S.A. 2008. Aspects of the biology, ecology and parasitism of Acanthomytilus sacchari (Hall) (Hemiptera: Diaspididae) on sugarcane in Egypt. Proceedings of the XI International Symposium on Scale Insect Studies, 322 pp.