Pest categorisation of Blissus insularis

Abstract

The EFSA Panel on Plant Health performed a pest categorisation of Blissus insularis (Hemiptera: Heteroptera: Blissidae) for the European Union (EU) territory. B. insularis, known in the US as the southern chinch bug, primarily feeds on St. Augustine grass (Stenotaphrum secundatum, Poaceae, subfamily Panicoideae). This is a lawn grass grown in warm, tropical and subtropical regions of the world and which is widely grown in the southern US and also used in southern EU as a lawn and amenity grass. Adults and nymphs aggregate to feed at the base of the grass. B. insularis occurs in the southern continental US, Hawaii, Guam, Mexico, Central and South America, and across the Caribbean. In the EU, B. insularis was first detected in Portugal in 2019, where following a national survey, it has now been found in 10 municipalities across the central and southern parts of the country. The pathway for entry into Portugal is unknown. B. insularis is not a regulated pest in the EU. It could further enter and spread within the EU via the import and movement of host plants for planting. S. secundatum is vegetatively propagated because seed is largely sterile. Many Poaceae plants for planting are prohibited from entering the EU, other than some ornamental perennial grasses. Whether S. secundatum is considered an ornamental grass within phytosanitary legislation is not clear. Host availability and climate suitability suggest that southern EU regions extending from the Atlantic coast of Portugal through the Mediterranean would be suitable for B. insularis establishment. The introduction of B. insularis to such areas of the EU would likely cause impacts to St. Augustine grass, as already seen in Portugal. Measures to prevent further entry and spread are available. Options to reduce the impact of established populations are also available. B. insularis satisfies all the criteria that are within the remit of EFSA to assess for it to be regarded as a potential Union quarantine pest.

Keywords: St. Augustine grass; pest risk; plant health; plant pest; quarantine; southern chinch bug.