Challenge your understanding of arecanut disorders impacting leaf coloration, growth, and productivity. Review key symptoms, causes, and management strategies relevant to arecanut cultivation.
What is the most likely cause of widespread yellowing of arecanut palm leaves starting from the older leaves and progressing to younger ones?
Explanation: Nitrogen deficiency in arecanut causes progressive yellowing from older to younger leaves because nitrogen is mobile in plants and gets translocated to new growth. Bud rot typically affects the crown with softening tissues, not general leaf yellowing. Mites cause localized spots or streaks, and sun scorch results in patches of bleached tissue rather than uniform yellowing.
Arecanut leaf spots with brown necrotic centers and yellow halos are indicative of which disorder?
Explanation: Leaf spot caused by Phyllosticta features characteristic spots with brown centers and yellow margins, differentiating it from yellow leaf disease, which results in more generalized yellowing, and koleroga, which primarily affects fruits and spikes. Iron toxicity generally leads to marginal leaf burn, not such distinct spots.
Which factor is most closely associated with the onset of Yellow Leaf Disease in arecanut plantations?
Explanation: Yellow Leaf Disease is linked to phytoplasma infection, which disrupts normal growth and produces yellowing and decline. Overwatering can cause root problems but is not the main cause of this disease. Magnesium toxicity and calcium deficiency present different symptoms, not the classic leaf yellowing with necrosis seen in this disorder.
If the youngest leaves of an arecanut palm show interveinal yellowing while older leaves remain green, which nutritional deficiency is most probable?
Explanation: Iron deficiency primarily affects the younger leaves, resulting in interveinal yellowing as iron is immobile in plants. Boron deficiency causes deformed growth rather than specific leaf yellowing. Potassium and phosphorus deficiencies appear first on older leaves due to their mobility, rather than on young foliage.
Which management practice is most effective in correcting zinc deficiency-induced leaf yellowing in arecanut?
Explanation: Soil application (or foliar spray) of zinc sulfate is effective for correcting zinc deficiency in arecanut, addressing the root cause. Foliar calcium nitrate addresses calcium issues but not zinc. Simply watering more won't solve nutrient deficiency, and urea supplies nitrogen, not zinc.