Chickpea cyst nematode

Chickpea cyst nematode (Heterodera ciceri) is an exotic plant pest not present in Australia. This nematode is a serious threat to Australia’s pulse industry.

Chickpea cyst nematode (Heterodera ciceri) is a plant-parasitic nematode that is an aggressive pest of chickpeas. Young chickpea cyst nematodes infest the roots of chickpea crops while the adult female nematodes become egg filled cysts.

Notifiable status

Chickpea cyst nematode (Heterodera ciceri) is not a notifiable plant pest in NSW.

However, if you suspect chickpea cyst nematode (Heterodera ciceri):

• Call the Exotic Plant Pest Hotline 1800 084 881
• Email biosecurity@dpi.nsw.gov.au with a clear photo and your contact details

A full list of notifiable plant pests and diseases can be found in Schedule 2 of the NSW Biosecurity Act 2015.

Description

Chickpea cyst nematodes are small worms which live on plant roots. Female nematodes look like small white or yellow lemon-shaped balls sticking out of the root. These pinhead-sized balls are about 1 mm wide. Male nematodes are hard-to-see tiny, threadlike, transparent worms.

The yellowing or stunting of chickpea crops is an early sign of infestation (Figure 1).

Patches of stunted plants may also appear in the infested crop. Poor canopy closure, few flowers or pods, reduced seed size, plant dieback or early plant death are other signs of infestation.

Chickpea cyst nematodes cause dark coloured streaks or lesions on the crop roots. Infestations may be confirmed by sighting white or yellow female nematodes or brown cysts on the roots. Female nematodes or cysts are smaller than the Rhizobium nodules on the plant roots (Figure 2).

Damage

Chickpea cyst nematode crop losses range from 20% in fertile soils to complete crop failure under low rainfall conditions. Yield losses of 20, 50 and 100% can be expected in chickpea fields infested with 8, 16 and 32 or more eggs per cubic centimetre of soil.

The chickpea cyst nematodes damage the plant roots and reduce root nodulation, causing nutrient deficiency symptoms to increase and requiring extra fertilizer to curb yield losses. When looking for this pest care needs to be exercised as chickpea cyst nematode damage can appear similar to the effects of drought stress, nutrient deficiency or herbicide damage.

Lifecycle

The chickpea cyst nematodes have three lifecycle stages: eggs, juveniles and adults.

Juvenile nematodes emerge from the eggs after rain. The juvenile females invade the host plant root tips and establish feeding sites. Egg hatch-ing and root penetration are suppressed at soil temperatures below 8°C and at or above 30°C.

As they grow the female nematodes swell up with eggs and rupture the plant root. When the adult females die their egg-filled bodies harden and become nematode cysts, which change colour from yellow to brown.

The average egg decline in cysts in soil without host plants is about 50% per annum. As the egg-filled cysts are resistant to dehydration, the eggs inside them can remain viable for several years.

Chickpea cyst nematodes complete one lifecycle in a cropping season and each female nematode lays up to 400 eggs.

Host range

The major host plant of chickpea cyst nematode is chickpeas.

Minor hosts include cowpea, field pea, garden pea, grass pea and lentil.

Beans, broad bean, crimson clover, lucerne, lupins, red clover and vetch are also infested by chickpea cyst nematode.

Spread

Chickpea cyst nematodes can be spread in cyst infested plant material or soil particles by water, wind, farm machinery, vehicles, humans, footwear and livestock.

Juvenile nematodes can move through the soil from their eggs to host plants.

Distribution

Chickpea cyst nematodes have been found in Italy, Jordan, Lebanon, Spain, Syria and Turkey.

Actions to minimise risks

Put in place biosecurity best practice actions to prevent entry, establishment and spread of pests and diseases:

• practice “Come clean, Go clean”
• ensure all staff and visitors are instructed in and adhere to your business management hygiene requirements
• source seed of a known high health status from reputable suppliers
• monitor your crop regularly
• keep records