Australasian Association of Nematologists

Quarantinable nematodes

A draft list of quarantinable plant pathogens was recently circulated by AQIS to quarantine plant pathologists in each State for comment. This list included bacteria, fungi, viruses, phytoplasmas and plant parasitic nematodes. The nematode list was notable for its brevity. It included only seven nematode species whereas there were several hundred species of quarantinable fungi.

The quarantinable nematodes included on the list were Aphelenchoides besseyi (white tip of rice), Bursaphelenchu xylophilus (pinewood nematode), Ditylenchus angustus (Ufra disease of rice), Globodera pallida (potato cyst nematode), Globodera rostochiensis (potato cyst nematode), Heterodera glycines (soybean cyst nematode) and Heterodera zeae (maize cyst nematode).

Organisms included on the final list will have an important status. Some of the implications of an organism being classed as quarantinable are: the species will be considered in the development of protocols for importation of agricultural commodities, the species will included in pest risk assessments, the species will be considered for targeted surveillance, the species will be considered for active containment or eradication following the detection of an incursion, and there will be a notification obligation following the detection of an incursion so the States are informed and can take appropriate action on interstate quarantine if justified.

To highlight the point that the draft list was grossly under-worked for plant parasitic nematodes, the following list of Heterodera species and their potential pest status was prepared. The assessment is based on a brief and limited review of the literature and is intended only to illustrate that the quarantine status of Heterodera spp. has not been adequately addressed.

Heterodera sp.	Common name	Hosts	Present in Australia	Quarantine pest status
H. avenae	Cereal cyst nematode	Wheat, barley	NSW, SA, TAS, VIC, WA	Races are likely
H. bifenestra		Grasses and cereals	Not present	Apparently of low pest status
H. cajani	Pigeonpea cyst nematode	Pigeonpea, Cowpea, Mungbean	SA	Limited distribution in Australia
H. carotae		Carrot	Not present	Potential serious pest
H. ciceri	Chickpea cyst nematode	Chickpea and some other legumes	Not present	Potential pest
H. cruciferae		Cruciferous hosts	Not present	Minor pest
H. cynodontis		Cynodon dactylon	Not present	?
H. cyperi		Ligustrum japonicum	Not present	Low pest status
H. daverti		Subclover	Not present	Serious in Tunisia
H. elachista		Rice	Not present	Potential pest
H. fici		Ficus spp.	NSW	?
H. galeopsidis			Not present	?
H. glycines	Soybean cyst nematode	Soybean	Not present	Quarantine
H. goettingiana	Pea cyst nematode	Pisum sativum	Not present	Considered a serious pest
H. graminis			Not present	?
H. hordecalis		Cereals and grasses	Not present	Apparently of low pest status
H. humuli	Hop cyst nematode	Humulus lupulus	TAS	Host limited
H. iri		Grasses, including turf grasses	Not present	Potential pest
H. latipons		Cereals and grasses	Not present	Potentially a serious pest
H. lespedeza		Lespedeza spp.	Not present	?
H. leucilyma		Stenotaphrum secundatum	Not present	?
H. longicaudata			Not present	?
H. mani		Agrostis spp. and ?other	Not present	?
H. marioni			Not present	?
H. maydis			Not present	?
H. medicaginis		Lucerne	Not present	Potential pest
H. oryzae	Rice cyst nematode	Rice	Not present	Serious pest, limit distribution
H. oryzicola		Rice, banana	Not present	Potential pest
H. sacchari	Rice cyst nematode	Rice	Not present	Potential pest
H. salixophila		Salix sp.	Not present	?
H. schachtii	Sugarbeat cyst nematode	Various	NSW, QLD, SA, VIC, WA	Should be non-quarantinable
H. sorghii		Sorghum	Not present	?Pest, limited distribution
H. trifolii	Clover cyst nematode		NSW, QLD, VIC, WA	Should be non-quarantinable
H. urticae	Nettle cyst nematode		Not present	?
H. vigna		Cowpea	Not present	?
H. zeae	Corn cyst nematode	Maize and other cereals	Not present	Quarantine

Given that the above list is restricted to Heterodera spp., it suggests that there is likely to be a large number exotic plant parasitic nematodes identified as potential quarantine pests if a wider analysis was done. Although few nematodes are likely to be introduced through normal agricultural trade, there are many routes of entry, most outside the control of Australian quarantine authorities. Without adequate recognition of the potential pest status of exotic plant parasitic nematodes, it is possible for new pest to become widely established before its importance is recognised and the option for response considered.

I would pleased to hear comment of members on the above situation and to explore options by which the association can bring to the attention of AQIS the need for giving exotic plant parasitic nematodes due consideration.

Ian Riley, Agriculture Western Australia

	July 1997: contents	July 1997: Radopholus