Regional Workshop on Fusarium oxysporum f. sp. cubense (Panama disease)Center for Research on Public Administration (CICAP)

University of Costa Rica (UCR)San Jose, Costa Rica, 1-3 September, 2014

Plutarco Elías Echegoyén Ramos, Agr. Eng., M.Sc.Plant Health SpecialistOrganismo Internacional Regional de Sanidad Agropecuaria - OIRSA

Sowing susceptible banana to Foc

Sowing of apparently Foc free propagative material, of a susceptible cultivar (Apple), within a coffee plantation (Santa Ana volcano, El Salvador) without traces of banana crop. Plants disappeared as time went by, due to the disease. More than 30 years ago, the property had been cultivated with banana for animal feeding.

Transfer of susceptible plants (Apple cultivar), apparently Foc free, to proximity of other varieties (Santa Ana volcano, El Salvador). Foc seriously attacked these transferred plants, and one of the adjacent cultivars (squarish angular dwarf, type bluggoe) also resulted severely affected (poultry dispersed the disease)

Identifying a susceptible plantation…

Experiences later described, occurred in this plantation.

Sampling techniques (with knife)

Process from left to right. This sampling technique, developed by the author, produced good results.

Sampling techniques (with borer)

This technique showed difficulties for sample surface disinfection at the laboratory. The culture media gets too contaminated, and the sought disinfection is not achieved.

Sampling techniques (with Novak curette)

Difficulty for sample surface disinfection at the laboratory. The culture media results too contaminated.

Control technique (gradual suppression)…

History of these three plants is described by photographical illustration, against a Focattack. On this date (9 June, 2013) they looked healthy and not infected by Foc

Control technique (gradual suppression)… cont. 2

These symptoms of Foc were photographically recorded on July 7, 2013; approximately 1 month after having observed the plant apparently healthy (see previous photos).

Control technique (gradual suppression)… cont. 3The pseudo stem of the first sick plant was cut at 15 cm over the soil surface on July 17, 2013 (note the stimulus that provoked the sprout of suckers in this plant, a lot more that the plant beside, with bunch)

The stump of the pseudo stem was covered with a PVC cylinder, which was filled with hydrated lime (calcium hydroxide) and covered. The collected sample resulted positive to Foc

Control technique (gradual suppression)… cont. 4

On July 21, 2013, the second plant of the cluster showed symptoms. The proceeding before described, was repeated

Control technique (gradual suppression)… cont. 5Likewise, on 21 July, 2013, a sucker of the cluster was observed with Foc symptoms (near the plant with bunch), so major pruning and the same treatment were applied.The same day, plant with bunch (center)was harvested.See the followingslides.

Control technique (gradual suppression)… cont. 6Apparently, the plant with bunch remained Focfree till harvest. The plant was sampled post harvest. When sectioning the pseudo stem, typical symptoms of Foc were observed (harvest was performed on 21 July, 2013). It was positive to Foc.

Control technique (gradual suppression)… cont. 7

Destruction procedure (by fire) applied to the aerial parts (leaves and pseudo stem) of the pruned plants of the cluster that were visibly diseased with Foc (the plant with bunch, although did not appeared infected, when sampled, showed symptoms of Foc, so it was major pruned and incinerated).

Control technique (gradual suppression)… cont. 8

Bunch of infected plant, near a plant of dwarf horn plantain. Samples were collected at both ends of the rachis, before and after the fruits, that resulted positive to Foc.

Cluster without the adult plants; two were eliminated for being visibly infected with Foc; and the other for showing symptoms post harvest.

Control technique (gradual suppression)… cont. 9

Note: the technique was not effective, it was impossible to contain the attack of the disease.

Pictures were taken in November and December 2013 (from left to right). Plants although being young already showed symptoms of Foc.

Spreading of FocThe spread of Fococcurred to the adjacent property, due to the overflow of the blind ditch that had been constructed to retain runoff from the plot with Foc-infected plants (pictured right).

It is believed that wild animals, such as armadillos (Dasypusnovemcinctus) whose traces are illustrated and other organismsthat carry or remove soil can spread Foc.

Spreading of Foc

Spreading of Foc

It is probable that infection of the Majoncho San Andrés observed is due to spread of the fungus from the apple banana plants in the vicinity.Soil carried on shoes (even with protection) may contain infectious fungal structures.

Removal of plants

It is believed that the removal of infected plant debris, both aerial and underground, can help lower the amount of inoculum of the pest and thus also contribute to its control. To achieve this, during dry weather (no rain) was applied incineration, and during wet weather (rainy season), treatment with formalin fumes and immersion of the material in a solution of formalin.

Burying of material treated with formalin fumes and solution of formalin.

Removal of plants

Recommendations

Avoid planting susceptible cultivars of Focwith material suspected of being infected; if so, use certified pathogen-free material; Exert Foc surveillance and determine

composition of populations present in different areas.

• Foc can survive in soil for a long time, probably over 40 years, so a ground where the pest has occurred, should be considered infected and not suitable for planting susceptible cultivars (unless it is disinfected);

• Susceptible cultivars (certified Foc-free) should be planted in soils with no history of banana cultivation or planted in soils where susceptible varieties are grown and has not reported any case of Foc (Foc-free areas or places with history of banana crops).

Recommendations… cont.

• Keep a detailed registry of areas or places where Foc cases have been present (if possible with Foctype present);

• Remove all plant material from Foc infected plants (to reduce the inoculum on the site and therefore its mobilization through media that is not propagation material);

• Declare (that implies to regulate) Foc as a regulated non-quarantine pest (see definition of regulated non-quarantine pest in ISPM No. 5).

Recommendations… cont.