Detection of Striga asiatica near Mackay, mid east coast, Queensland

Date de publication

lun, 22 Jul 2013, 00:00

Dernière mise à jour effectuée le

juil. 6, 2023, 5:54 matin

Report Number

AUS-56/4

Pays

Australia

Identité de l'organisme nuisible

Striga asiatica - (STRLU)

Situation du signalement

Préliminaire

Hôtes

Sugarcane (Saccharum officinarum)

Pest Status (old values from ISPM 8 -1998 )

• Present: only in some areas
• Present: subject to official control

Pest Status (ISPM 8 - 2021)

• Present: not widely distributed and under official control

Distribution géographique

Detected on a single sugarcane property near Mackay, in an isolated part on the mid east coast of Queensland, 1000 kilometres north of Brisbane. S. asiatica has not been detected in any other area in Australia during routine surveillance of all grain crops which include specific surveys targeting S. asiatica.

Résumé

Symptoms in host plants include stunting, chlorosis, and wilting. Seedlings are not visible above ground, but white succulent shoots can be found attached to host roots. Underground stems are round with scale-like leaves and white, turning blue when exposed to air. The roots are succulent, round, without root hairs and found attached to a host species root system. Mature plants have green foliage above ground which is sparsely covered with coarse, short, white, bulbous-based hairs. Plants are normally 15–30cm tall. Leaves are nearly opposite, narrowly lanceolate, about 1–3cm long, with successive leaf pairs perpendicular to one another. It flowers in summer and autumn, with small (less than 1.5cm in diameter) flowers, which are sessile and axillary, occurring in loose spikes. Flower colour varies from bright red to white, yellow or pink. Flowers self-pollinate before opening. S. asiatica is distinguishable from Australian native species as its calyx has 10 ribs, whilst native species have calyces with 5 ribs. Capsules can contain up to 1400 seeds (550 average). Brown seeds about 0.2mm long are dispersed by wind, water, soil movement, human activities and by clinging to the feet, shoes and clothing, animals, farm machinery, tools. It is native to tropical parts of Asia and Africa, including the Philippines, Cambodia, Indonesia, China, Malaysia, Thailand, Vietnam, Mauritius, India and the Arabian peninsula. It has been introduced to the United States.

Danger

S. asiatica is an obligate parasitic of Poaceae, especially crop plants maize, sorghum, rice and sugarcane, and sometimes wheat, barley, millet and others. Other genera may also be hosts: Digitaria, Paspalum, Echinochloa, Imperata, Pennisetum, Cynodon, Chrysopogon, Elionurus, Eleusine, Eragrostis, Loudetia, Hyparrhenia.

Contact pour demandes d'information

Australian Chief Plant Protection Officer Australian Government Department of Agriculture, GPO Box 858 Canberra ACT 2601 Australia [email protected]

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