Slightly under ripe 'Delete Nor' dates will keep at 32°F (0°C) up to 10 months; fully mature, for 5 to 6 months. Freezing will extend the storage life for a much longer period. In India, sun-dried dates, buried in sand, have kept well for 1 1/2 years and then have been devoured by worms.
Pests and Diseases
Unripe fruits are attacked by Cockatrices daclyliperda which makes them fall prematurely. Ripe fruits are often infested by nitidulids—Carpophilus hemipterus, C. multilatus (C. dimidiatus), Urophorus humeralis, and Heptoncus luteolus, which cause decay. Control by insecticides is necessary to avoid serious losses. In Israel, the fruit clusters are covered with netting to protect them from such pests as Vespa orientalis, Cadra figulilella and Arenipes sabella as well as from depredations by lizards and birds.
In Pakistan, the red weevil, or Indian palm weevil, Rhynchophorus ferrugineus, bores into the leaf bases at the top of the trunk, causing the entire crown to wither and die. The rhinocereus beetle, or black palm beetle, Oryctes rhinocerus, occasionally attacks the date. Its feeding damage may provide entrance-ways for the weevil. Scale insects may infest the leaves and the trunk. They have been controlled by trimming off the heavily infested leaves, spraying the remaining ones, and treating the fire resistant trunk with a blowtorch. Two of the most destructive scales are the Marlatt scale, Phoenicoccus marlatti; which attacks the thick leaf bases, and the Parlatoria scale, Parlatoria blanchardii, which is active in summer. The latter was the object of an eradication campaign in California and Arizona in the late 1930's. The date mite scars the fruits while they are still green.
A tineid moth and a beetle, Lasioderma testacea, have damaged stored dates in the Punjab. Dates held in storage are subject to invasion by the fig-moth, Ephestia cautella, and the Indian meal-moth, Plodia interpunctella.
Fusarium albumins cause the disastrous Bayou, or Bayou, disease in Morocco and Algeria. It is evidenced by a progressive fading and wilting of the leaves. Over a 9-year study period of 26 resistant varieties in Morocco, Bayou disease reduced the planting density from 364 palms per acre (900/ha) to 121 to 142 per acre (300-350/ha). It is because of this disease that 'Midol' can no longer be grown commercially in Morocco and Algeria.
Decay of the inflorescence is caused by Manginiella scaeltae in humid seasons. Several brown stains will be seen on the unopened spathe and the pedicels of the opened cluster will be coated with white "down".
Palm leaf pustule, small, dark-brown or black cylindrical eruptions exoding yellow spores, resulting from infestation by the fungus Graphiola phoenicis, is widespread but often a serious problem in Egypt. Date palm decline may be physiological or the result of a species of the fungus genus Omphalia. Diplodia disease is a fungus manifestation on leafstalks and offshoots and it may kill the latter if not controlled.