Hartrot and Marchitez Sorpresiva
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Figure 1. Chlorosis and necrosis of leaf tip of older leaf of Elaeis guineensis affected by Marchitez Sorpresiva/sudden wilt/lethal wilt. Photo by M. L. Elliott.
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Figure 2. Elaeis guineensis affected by Marchitez Sorpresiva/sudden wilt/lethal wilt in late stages of disease surrounded by healthy palms. Dead leaves have formed skirt around trunk. Photo by M. L. Elliott.
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Other common names
Hartrot (fatal wilt) and Marchitez Sorpresiva (sudden wilt, lethal wilt))
Scientific name of pathogen
Phytomonas spp.: Kingdom Protozoa, Phylum Euglenozoa
Hosts
Cocos nucifera (hartrot/fatal wilt), Elaeis guineensis (Marchitez Sorpresiva/sudden wilt)
Distribution
Brazil, Colombia, Costa Rica, Ecuador, French Guiana, Grenada, Guyana, Honduras, Nicaragua, Peru, Surinam, Trinidad & Tobago, Venezuela
Symptoms/signs
Initial symptoms are observed on the oldest leaves in the canopycanopy:
the cluster of leaves borne at the tip of the stem
, with two or three leaves discoloring at the same time. The leaf tips of these leaves become chloroticchlorotic:
see chlorosis
and then necroticnecrotic:
see necrosis
(Fig. 1), and this discoloration then progresses to the leaf baseleaf base:
the basal portion of a leaf petiole that is attached to the stem
. This leaf discoloration continues up through the canopycanopy:
the cluster of leaves borne at the tip of the stem
. While the leaves remain attached to the trunk, they often break and form a skirt of leaves around the trunk (Fig. 2). Fruits either drop or rot prematurely. Inflorescences rot, and the palm ceases to flower. First order root tips begin to rot as the leaves discolor. When most of the leaves are brown, the spear leafspear leaf:
the younges emerging leaf that has not yet opened
and apical meristemmeristem:
the growing region of a plant, a special area of undifferentiated cells wherein new cells and organs are developed
(bud) rot, but this is probably due to secondary microbial infections.
May be confused with
Lethal yellowing of Cocos nucifera and red ring of Cocos nucifera and Elaeis guineensis also cause similar symptoms, but the progression of symptoms and leaf discoloration pattern is usually different. Phytomonas pathogens that cause hartrot and Marchitez Sorpresiva can be observed with the aid of a light microscope by examining sap from inflorescences.
Additional comments
This disease is not normally observed until Cocos nucifera is 3 to 4 years old or Elaeis guineensis is 2 years old.
The protozoan is vectored by insects in the order Hemiptera.
