Pests & Diseases
While there are few pests and diseases that affect turmeric, the most serious pest is the shoot borer. Other pests of concern include thrips, rhizome scale, and nematodes. The few diseases to which turmeric is susceptible include rhizome rot, leaf spot, and leaf blotch.
Storage & Packaging
Harvested rhizomes are soaked in water to remove excess dirt. Mother rhizomes are usually saved for planting and stored in well-ventilated rooms, covered with dry leaves to prevent both rot and dehydration. For rhizomes going to market, long roots and leaf scales are removed before curing.
Rhizomes are cured 2 to 3 days after harvest and boiled until soft enough to yield to finger pressure or be pierced. Steam boiling can be an alternative to immersion. Cured rhizomes dry faster than uncured and are less wrinkled and easier to polish.
Cured fingers or bulbs are dried to about 5 to 10% moisture level either via sun or mechanically; the latter is preferred as rhizomes are sensitive to light and moisture.
Drying temperature is about 140°F. After drying, rhizomes are sorted into grades of fingers, bulbs, and splits before polishing to improve appearance. Polishing consists of mechanical rubbing, sometimes with a mixture of turmeric powder and water sprinkled in during the last phase.
References: Florida Gulf Coast University, Food and Agriculture Organization of the United Nations, Tamil Nadu Agricultural University, University of Florida/IFAS Extension, University of Maryland Medical Center, USDA.