Dates (Phoenix dactylifera) are the sweet fruit of a palm tree and believed to have originated in the Middle East centuries ago. They were brought to the Americas, specifically California and Mexico, in the 1760s and have been cultivated ever since.
Types & Varieties
Dates are categorized as soft, semisoft, and dry depending on moisture content at the time of ripeness or harvest. Dry dates are also called ‘bread dates.’
Exterior color of the fruit can vary from yellow to red or amber, as well as dark brown and nearly black. Skin thickness, texture, and sweetness depend on variety. Size generally ranges from 1 to 3 inches.
Well over a thousand varieties of dates can be found around the world; among the prevalent are Abada, Amhat, Bahri, Barthee, Bentaisha, Halawy, and Honey for soft dates (those with up to 30% moisture).
Amry, Dayri, Deglet Noor, Khalasa, the well-known Medjool (very popular in the United States), Sewy, and Zahidi are semisoft varieties (from 20 to 30% moisture). Badraya, Bartamoda, Deglet Beida, Horra, Saokoty, and Thoory for dry dates (less than 20% moisture content).
Fruit growth is usually divided into five stages of development known by the Arabic terms hababouk, kimri, khalal, rutab, and tamr. Most dates are harvested at the tamr stage, when the fruit has about 60 to 80% sugar content.
At this stage, fruit can be harvested soft, semisoft, or dry, depending on destination and use. Some varieties with low tannins but rich in sugar can be harvested at the khalal stage.
High-quality fresh dates should have small pits and thick flesh. They should be free of dirt, sand, and leaf particles; bird, insect, and rodent damage; fungi and mold infestation; sugar crystal formation; or any other apparent alterations. The skin of dates should be smooth, with little or no shriveling; and a gold-brown, amber, green, or black color depending on variety.
The texture may be soft and syrupy or firm and dry, depending on the cultivar.
Pests & Diseases
Since most date palms grow in hot, dry regions, major pest problems are rare. A few examples include scale, which affects leaves, fruit stalks, or roots. Heavy infestations can completely cover leaf surfaces and prevent growth. Carob moths lay eggs on dates and larvae bore into the fruit, while other types of moths have been found in stored dates, causing damage. Beetles feed on leaves and fruit stalks, affecting growth, and can kill the palm, while termites can feed on roots and bore their way through offshoots, killing them, and can tunnel through trunks, weakening palms so they eventually collapse. Other pests can include mites, mealybugs, palm weevils, and worms.
Black scorch is evidenced by blackened leaves and will stunt growth and cause rot in trunks and buds. Diplodia produces yellow-brown streaks on leaves and can weaken and kill newer, young leaves. Leaf spot also affects leaves, which can reduce yields and lifespans by half. Various types of fusarium can cause wilting in leaves and lead to other diseases.
Root rot is responsible for the premature death of palm fronds, preventing growth and eventually leading to root destruction. Lethal yellowing is a pathogen common to coconut trees, but in date palms, fronds turn greyish brown and slimy with soft rot, eventually falling off the tree. Heavy rain or excessive moisture can cause fungal growth, though it is uncommon. Other diseases can include blight and white rot.
Storage & Packaging
At the optimal storage temperature of 32°F with 75% humidity, soft dates can be stored for up to 6 months, while semisoft dates can last up to a year. Dates are not sensitive to chilling injury, but do produce ethylene.
References: Purdue University, UC Davis Postharvest Technology Center, University of Arizona, University of California Cooperative Extension, USDA.