Cabbage growers from the Northern Adelaide Plains have teamed up with TriCal Australia and the South Australian Research and Development Institute to conduct soil fumigation trials that focus on suppression of beet cyst nematode. Vegetables Australia has been provided with the results from the preliminary survey and trial, which were conducted in late 2019 and throughout 2020.

TriCal Australia General Manager Matthew Stein has been investigating the effectiveness of soil fumigation using Strike 35 (35 per cent Chloropicrin, 65 per cent Telone) as an effective suppression agent against beet cyst nematodes.

Located in Virginia, South Australia, Frank and Rocco Musolino’s farms were surveyed in November 2019 after growers – through AUSVEG SA – approached TriCal Australia and the South Australian Research and Development Institute’s (SARDI) nematology group, headed by Michael Rettke. This was part of a preliminary project that evaluated the effectiveness of Strike 35 in increasing cabbage yields and returns to growers located on the Northern Adelaide Plains.

Preliminary survey results showed that beet cyst nematode cysts ranged from 5-54 cysts per 250 grams of soil. These levels were producing wastage levels of up to 60 per cent in cabbage crops.

Image 1: Stunted cabbage plant growth due to high beet cyst nematode numbers (54/250g soil).

Case study: Virginia, South Australia

A 2-ha soil fumigation trial was established in June 2020 on Chris Musolino’s farm at Virginia, with three fumigation treatment blocks and a no fumigation control. Soil samples were taken on each treatment block in June – before the trial began – and further soil samples were collected in August and later in October. These soil samples were sent to SARDI’s nematology group, and samples were visually analysed for cyst and egg numbers.

Image 2: Three-metre-wide soil fumigation rig.

The 2-ha trial was located on a clay loam soil that is on the Gawler River flood plain. This soil is prone to water inundation and periodic flooding. The trial area was divided into three fumigation treatment blocks (2 x 300kg/ha of Strike 35; 1 x 500kg/ha of Strike 35), and a control block that was rotary hoed on three separate occasions to control weeds before being planted to cabbage seedlings. The plantings were staggered, with the 300kg/ha area planted first followed by the 500kg/ha block then the second 300kg/ha block, and finally the control block. Irrigation was applied via standpipe sprinkler irrigation using Bolivar recycled water.

The soil was fumigated by applying the fumigant via injection tines to a depth of 40cm and then rolling the soil to form a seal in one pass (see Image 2). The fumigated ground was then left 14 days before seedlings were planted.

Before soil fumigation was started, soil samples were collected from each treatment for analysis of beet cyst nematode numbers. The trial site had a wide variability of cyst numbers as can be seen in the treatments.

Preliminary results

Image 3: Strike 35 300kg/ha – Excellent plant health.

The fumigation blocks have seen cabbage plant growth exceed expectations, with harvest yields increasing from 60 per cent to over 80 per cent. Head size of the cabbages for green smooth, green rough, and red have increased by one-third.

Soil sampling is continuing to quantify the level of beet cyst nematode populations and initial results have indicated that the Strike 35 300kg/ha (see Image 3), and 500kg/ha (see Image 4), have produced excellent results.

At present, it appears that the Strike 35 300kg/ha rate gives the best economic outcome and best cabbage yield thresholds.

It has been seen that without soil fumigation, plant sizes are stunted, plant harvested material has dropped back below 60 per cent and beet cyst nematode numbers have dramatically increased (see Image 5).

SARDI is continuing to test both soil and plant samples to verify that there are no other pests and diseases involved in reducing yield potentials. This trial was due to conclude in December 2020.

Image 4: Strike 35 500kg/ha – Excellent plant health.

Find out more

Please contact AUSVEG SA Chief Executive Officer Jordan Brooke-Barnett on 0404 772 308 or at jordan.brooke-barnett@ausveg.com.au or TriCal Australia General Manager Matthew Stein on 1300 FUMIG8 (1300 386 448) or at mstein@trical.com.au.

Image 5: Control unfumigated – Poor plant health.