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

Publication Date
Mon, 22 Jul 2013, 02:00
Last Updated
June 30, 2015, 8:28 a.m.
Report Number
AUS-56/4
Country
Australia
Pest Id
Striga asiatica - (STRLU)
Report Status
Preliminary
Hosts
Sugarcane (Saccharum officinarum)
Pest Status
  • Present: only in some areas
  • Present: subject to official control
Geographical Distribution
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.
Summary

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 for info
Australian Chief Plant Protection Officer Australian Government Department of Agriculture, GPO Box 858 Canberra ACT 2601 Australia ippc.contactpoint@agriculture.gov.au
Issue keywords
Pest reporting
Commodity keywords

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