Field assessment of calcium, copper and zinc ions on plant recovery and disease severity following infection of Huanglongbing (HLB) disease
Keywords:
Huanglongbing, candidatus liberibacter asiaticus, field assessment, micronutrients and macronutrients.Abstract
The effect of Ca, Cu and Zn ions on plant recovery and disease severity following infection of
huanglongbing disease was carried out at a commercial citrus orchards belonging to Lembaga
Pertubuhan Peladang (LPP) Terengganu, situated at Durian Mentangau, Dungun, Terengganu.
Application of Zn or Cu ions in combination with Ca was able to delay disease incidence and severity of
hunglongbing disease. These treatments (C/Ca/Cu and C/Ca/Zn) also showed slightly reduction of
AUDPC value on infected citrus trees. In general, analysis of macronutrients and micronutrients content
in citrus leaves showed significantly different at the beginning of the stud y (0 to 6 months after
treatment) but no significant different were observed at the end of the study period (6-9 months after
treatment) as noted on Mg, P, Ca and Zn analysis. Results for specific leaf area showed no significant
different among treatment as observed in leaf area, total leaf length and total leaf width. However,
specific leaf area was increased gradually in all treatments over the period of the study. The overall
results of field trial showed that infected citrus trees treated with combination of Ca and Zn ions at 600
and 10 ppm, respectively resulted in significant increase (P≤0.05) in terms of fruit production and total
soluble solid (TSS) content only.
