IS14027

Information Sheet

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Managing nematodes in sugarcane production: Burdekin

Nematodes

The two species of nematodes that cause serious damage to sugarcane are root lesion nematode Pratylenchus zeae. (RLN) and root knot nematodes Meloidogyne spp. (RKN). There are many other types of nematodes that can affect sugarcane, such as dagger and spiral nematodes, particularly if they are present in very high numbers. Distribution

Plant-parasitic nematodes (PPN) are widely distributed in cane growing soils, with at least five different species likely to be present in every cane field. The abundance and proportion of species will vary with soil type, climate and crop history. RKN are mainly found in the lighter, sandy soils, whereas lesion nematodes can be found in every cane-growing region in Queensland.

Damage

RKN and RLN enter through the root tips, while most other nematodes feed on the outer surface of the roots. Damage to the roots will depend on the species present. Typical symptoms are short, thickened and blackened primary roots with very few fine secondary or tertiary roots. RKN produces distinctive symptom of swelling and gall formation on the root tips. RLN produces the presence of many red lesions on root surface. It is believed that yield losses across all sugarcane soil in Australia are as high as 10 per cent (Plant) and 7 per cent (Ratoon). Where high nematode populations occur these figures are significantly higher.

Varieties

There are no known nematode resistant varieties in the suite of varieties recommended for the Burdekin region.

The Introgression project is a collaborative project between SRA and CSIRO that aims to develop nematode-resistance sugarcane varieties. In the program sugarcane is crossed with wild relatives of sugarcane that are resistant to nematodes.

Promising clones have been selected and will be evaluated in the field to verify the reliability of glasshouse tests, and also for productivity in the 2014 final assessment trials.

Above: This graph shows a number of promising clones in the introgresssion project.

Root knot Pratylenchus

Above: Root lesion nematode damage – red lesions.

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IS14027

Information Sheet

Management

• Monitor crops: a soil test which can confirm the species of nematode present can be arranged through your local productivity services group. Nematode counts are conducted at the SRA Tully assay laboratory.

A guide to nematode threshold levels:

• Avoid plough-out/replant where possible.

• Harvest plough-out blocks early to give a maximum break before planting legume crops.

• Include a legume rotation in your crop cycle. Soybean and peanut crops can reduce PPN numbers by 80-90 per cent.

A guide to the legume resistance to these two species of nematodes:

HS: Highly susceptible. Nematodes will multiply to high population densities

MS: Moderately susceptible: Nematodes will multiply readilyMR: Moderately resistant: Nematodes will multiply to some extent R: Resistant: Limited nematode reproductionHR: Highly resistant: No reproduction

• Ensure fallow crops are kept free of weeds and volunteer cane.

• Green cane trash blanket (GCTB). High populations of root lesion and root knot nematodes re-establish if a trash cover is not maintained. GCTB provides a better environment for beneficial organisms such as free living nematodes and predators of plant-parasitic nematodes.

• Minimum tillage systems which preserve the trash blanket between crops to help minimise populations of PPNs. Tillage operations kill beneficial nematodes, allowing PPNs to quickly re-establish.

• A number of chemicals are registered for nematode control in sugarcane. These includes Rugby® 100G, Nemacur® 100G (granules) and Nemacur® 400 (liquid). These nematicides also kill natural nematode enemies, and only reduce nematode populations for a short period of time.

Legume Root lesion nematode

Root knot nematode

Lablab (all cultivars) R HS

Cowpea (most cultivars) R HS

Cow Pea Meringa R MS

Soybean – Leichardt R HS

Soybean – A6785 R R

Soybean – Stuart R R

Soybean (most cultivars) R HS

Peanut (all cultivars) R HR

Velvet Bean (all cultivars) R R

Species

Common name

Threshold for plant & 1st ratoon

Threshold for older ratoons

Pratylenchus Root lesion 300 900 +

Meloidogyne Root knot 200 600 +

Above: Root knot nematode damage – galls.