The most commercially significant trial we have run. TR4 appeared on every treated lot. The difference was in degree.
Tropical Race 4 has spread rapidly and destroyed Cavendish banana farms. It is the strain of most concern to the Australian industry.
This trial ran on a 50 hectare Cavendish farm at Ban Vang Mieng, Vang Vieng, verified TR4-affected throughout, in co-operation with the Lao PDR Department of Agriculture. Agronomist: Moukdavanh Chanthavong.
The area was cleared of infected plants, contoured and fenced. Disease-free tissue-cultured Musa acuminata seedlings were planted at 2 m spacing, rows 3 m apart.
The Black Stuff was spread across the whole trial area at 3 tonnes per hectare. Within that, four sub-treatments:
| Lot | Additional treatment per plant |
|---|---|
| T1A | 400 g NPK |
| T1B | 400 g The Black Stuff |
| T1C | 200 g NPK + 200 g The Black Stuff |
| T4 | Control — no product at all |
Ordinary commercial practice. NPK 15:15:15 monthly at 150 g per plant. Data collected by the Department of Agriculture.
Signs of TR4 were found in T1A, T1B and T1C. Yellowing leaves and some split trunks across all treated lots. Black spot and yellow sigatoka were also present.
| Lot | Observed |
|---|---|
| T1A — NPK only | 30% of plants showing TR4 indications, yellowing leaves, some rotting trunks |
| T1B — humate only | Some yellowing leaves |
| T1C — split NPK and humate | Some yellowing leaves. Healthiest plants. Producing a crop. |
| T4 — control | All plants affected. All dead or dying. |
Plants on 3 tonnes per hectare and above showed strong growth and resilience under TR4 pressure that killed the untreated control outright. The best lot was the split treatment — half NPK, half humate — which was both the healthiest and the only one producing a crop.
The report's own conclusion is a four-part strategy, not a product claim:
TR4 was present on every treated lot. Nothing here prevented infection. What the trial records is that plants on treated ground kept growing and one lot carried a crop, while the untreated control died.
Note: the report should be read in full. Problems in the trial execution compromised results. Details are in the report.
The Black Stuff is a soil conditioner. It is not a fungicide, it is not registered as an agricultural chemical product, and it should not be bought as a treatment for Tropical Race 4. The trial ended early in March 2020 with the Covid-19 lockdown.
Cavendish TR4, Vang Vieng 2019–2020 · 15 pp. The Black Stuff is a soil conditioner and is not a registered agricultural chemical product. Nothing in this report is a claim that it controls, prevents or treats any plant disease.
Location — Ban Vang Mieng, Vang Vieng
Crop — Cavendish, Musa acuminata, tissue cultured
Farm — 50 ha, verified TR4 affected
Soil — sandy loam, pH 4.4
Rainfall — 3,300 mm annual
Spacing — 2 m × 3 m
Base rate — 3 t/ha across whole area
Agronomist — Moukdavanh Chanthavong, DoA
Ended — March 2020
