Date Palm Diseases A

Lecture To ToT trainees ( FFS)

By Mr. Allah Dad Khan

Provincial Coordinator IPM KPK

MINFAL Pakistan

Symptoms of Bayoud disease on date palm  Symptoms Leaflets of mature leaves becoming chlorotic at the base on one side; leaf death progressively to

the leaf tip; brown or white lesions on underside of leaves Cause Fungus Comments Soil-borne disease; currently restricted to Morocco and Algeria where it can be devastating; the

popularity of susceptible cultivars means it has a massive potential to continue to spread Management Cultural control is not recommended for the control of the disease as conditions which favor high

yield of dates also favors growth of the fungus; if disease is confirmed then infected tree should be uprooted and burned to prevent spread; soil should be treated with methyl bromide or chloropicrin and the area closed off

Bayoud diseaseFusarium oxysporum

 Dothiorella causes a severe browning of all the cortical tissues including the xylem elements giving a broad band of dark tissue (figure 2). If the samples are retained in a moist cool place, they will often form fruiting bodies (pycnidia) that erupt through the epidermis of the rachis (figure 3). Microscopic examination of the fruiting bodies and spores will confirm the diagnosis.  

Fusarium Wilt Dothiorella or Fusarium

Symptoms Dark brown-black, hard lesions on leaves; foliage with scorched

appearance Cause Fungus Comments Palms may recover from disease; fungi can enter

through pruning wounds Management Prune out infected fronds, leaf bases and

inflorescenses and burn the material immediately; pruning wounds should be protected by spraying with Bordeaux mixture

Black scorch disease Ceratocystis paradoxa

The pink rot disease of palms is perhaps the most ubiquitous palm disease in the landscape. It is caused by the fungus Gliocladium vermoeseni, (Pennicillium vermoeseni) a member of the fungi imperfecti. The perfect stage of the fungus is not known. The biology of the pink rot fungus is amazing in that it can produce billions of spores while growing on a single plant. Thus its spores are always present where palms are grown so there is no way to avoid it. The fungus is a weak pathogen in that it requires a wound or other plant stress factors that enable it to infect. 

Pink Rot

Symptoms Death of suckers either while still attached to mother or

after planting Cause Fungus Comments Fungus usually enters through cutting or pruning wounds Management Disinfect all tools and equipment regularly; protect

pruning wounds and cuts with Bordeaux mixture or other appropriate copper based fungicides

Diplodia disease Diplodia phoenicum

Graphiola leaf spot symptoms on date palm frond  Symptoms Small spots on both sides of leaves; yellow spore masses on leaves; black crater-like

lesions on leaves Cause Fungus Comments Disease emergence favored by high humidity Management Infected leaves should be pruned out and destroyed; disease can be controlled by

sprays of Bordeaux mixture or other appropriate broad spectrum fungicide

Graphiola leaf spot Graphiola phoenicis

The disease is called diamond scale because of the diamond shaped ascothecia or ascus bearing structures that form on the leaves of affected palms. Contrary to common belief, this is not a “scale” insect, but the fruiting body of the ascomycete fungus mentioned above.   The diamond shaped structures hold the sexual spores of the fungus. The asexual stage of the fungus (anamorph) has not been identified. Since not all the spore stages of the fungus are know, an accurate life history of the organism is impossible to discern.

Diamond Scale Disease

Symptoms of lethal yellowing on date palm  Symptoms Fronds drying out and turning gray-brown; growing tip rotting and turning into a slimy

mass with foul smell; crown collapses from trunk leaving a naked trunk Cause Phytoplasma Comments Disease is transmitted by planthoppers Management Disease severity can be reducced by injecting the antibiotic oxytetracycline HCl into

the trunk; antibiotics can also be administered as a protective measure if the disease is known to be in the area; control of the disease long term relies on planting resistant or tolerant varieties

Lethal yellowing Lethal yellowing phytoplasma