RESEARCH & EVENTS
Integrated disease management update: Agriculture Victoria team assessing for hull rot
By Tonya Wiechel and Simone Kreidl Agriculture Victoria Research, AgriBio Centre for AgriBiosciences, Bundoora
THIS season, Agriculture Victoria researchers continued monitoring hull rot expression in rootstock and planting density trials at the Almond Centre of Excellence( ACE). The focus remained on understanding how rootstock selection and orchard design influence hull rot development under Australian conditions. Last season demonstrated that both planting density and rootstock vigour play important roles in hull rot risk. This research forms part of the broader AL22001 Integrated Disease Management project funded by Hort Innovation. The second season of hull rot disease assessment data from Non pareil trees has recently been collected( Table 1 and 2). In the Low to Medium Density Optimisation Trial( SARDI Trial 3) the mean incidence of hull rot in 2026 was substantially lower( 1 – 3 hull rot strikes per tree) than in 2025( 4 – 20)( Table 1). Maximum values were also markedly reduced, five to 10 strikes in 2026 compared with up to 92 in 2025. This trend was consistent across all tree densities( 308 – 615 trees / ha), indicating a significant overall reduction in disease symptoms in 2026 relative to the previous season. In SARDI Trial 5 that focuses on evaluating rootstock
A
C
B
D
Figure 1. Nuts from hull rot strikes before( A & C) and after moist incubation( B & D).
Table 1. Hull rot strikes on NP across 6 planting densities in SAR- DI Trial 3.
compatibility and planting density there was an average of two hull rot strikes per tree in H2 plantings and three strikes per tree in H3( Table 2). This low level of hull rot makes it difficult to determine the best performing rootstocks this season. Last year, the denser H3 spacing consistently produced more strikes( average of 31 vs. 17 in H2). This pattern persisted, although at lower overall levels. Several rootstocks— notably Atlas, Controller7, RootPacR and RootPac40— recorded higher strikes in H3 compared with H2, showing that canopy structure remains a key risk factor.
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Table 2. Hull rot strikes on NP across 14 rootstocks in SARDI trial 5.
34 In A Nutshell- Autumn 2026 Vol 27 Issue 1