AGRITRENDS: Going bananas

Second of Three Parts

From its beginning in the late 1960s and spurred by the flourishing markets in Japan and the Middle East in 1970s, the banana export industry grew to become a multi-million business.  Banana has been consistently ranked among the country’s top exports.

But things are not always smooth-sailing for the banana industry, which contributed some US1.14 billion to the country’s economy in 2014.

“The industry is facing serious problems, if unsolved, it two to three years we can kiss the banana industry goodbye,” deplored Stephen A. Antig, the executive director of Pilipino Banana Growers and Exporters Association (PBGEA), in a press conference that was held at Apo View Hotel last year.

One of the serious problems that the banana industry faces is that of diseases that have wrought havoc on farms.  In Compostela Valley, for instance, one farm closed down its operations after 100 hectares was affected with a soil-borne disease.

Ten years ago, on November 28, 2008, Dr. Agustin Molina issued a warning that “a more virulent type of Panama disease” that attacks banana “has already made its appearance in the country.”

Dr. Molina, senior scientist and regional coordinator for Asia-Pacific of the Biodiversity International, sounded the alarm during a seminar convened at the Bureau of Agricultural Research (BAR).

Today, the Panama disease – also known as Fusarium wilt – is wreaking havoc among the banana plantation in Davao Region.   Caused by a fungal pathogen, “Fusarium oxysporum f. sp. cubense (Foc),” this soil-borne disease remains in an affected area for decades.

The Foc fungus is efficiently spread through water and irrigation systems, according to Dr. Molina.  The Panama disease reached Australia in 2006 due to the floods from cyclone Larry; it spread the disease to healthy banana plants.

Infection of the plant, Dr. Molina explained, is through injured roots of the banana plant. The fungus then invades the xylem vessels appearing as a reddish-brown discoloration and advances into the corm.  Eventually, the fungus affects the whole stem and above ground symptoms appear.

The Bureau of Plant Industry (BPI) says the usual signs of Panama disease infestation could be confusing such as the yellowing of the leaf margins of older margins which could be suspected as deficiency.  All of the leaves of infested plant wilt which can also be a sign of senescence or growing old.

Internal signs are more pronounce and can be seen by slicing off the lower portion of the corm horizontally until the transverse is cut about one-fourth of the way up to the corm.  The vascular tissues in the roots and corm are discolored, making the vascular stands in the pseudostem turn either yellow, red or brown.

“No trouble with Panama disease starts with the commercial banana itself,” wrote Victoriano Guiam in an article which appeared in “BAR Digest.”  “All of the Cavendish grown in the world are genetically identical, being but clones of the original plant.  Genetic diversity is absent because the plants are multiplied through vegetative reproduction as sexual reproduction is not feasible.  The lack of genetic variation is an assurance for the success of a marauding pathogen once it exploits the weakness of identical clones.  The disease of one is the disease of all.”

In his article, Guiam wrote that before the Cavendish banana became the usual table fare around the world, there was Gros Michel banana, which was planted across countries in Central America.

Gros Michel, a sweet banana with thick skin that is less prone to bruising during transport, was the variety of choice for the production of export bananas in the 1920s-1950s and at that time, made the Central America region the top banana-producing area in the world.

“Disaster struck in the mid-1950s when Panama disease turned on the Gross Michel banana,” Guiam wrote.  “Within a few years, wholesale destruction was seen in plantations in Central America and Africa with 50,000 hectares lost in Honduras alone.  This drove the banana business to near bankruptcy and precipitated the move to the relatively less delectable, but resistant, Cavendish banana.”

The Cavendish banana, which originated from Southeast Asia, replaced the Gros Michel variety on a global scale.  Billions of dollars in investments were reportedly spent beginning in the late 1960s for the development of infrastructure to accommodate differences in growing and ripening needs of the new variety in different countries.  All seemed well with Cavendish as the new banana of commerce until the Fusarium wilt Tropical Race 4 came along.

Dr. Molina said that in the banana business, Foc is conventionally classified into four pathogenic forms known as “Races.”  Race 1, which destroyed the Gros Michel plantations, also attack many local varieties in Asia.  Race 2 affects specific cooking bananas.  Race 3 attacks “Heliconia” species, ornamental plants that are related to bananas. Race 4 affects a wide range of cultivars, including Cavendish and cultivars susceptible to Races 1 and 2.

The extremely virulent strain of Race 4 – known as “Tropical Race 4” – is a relatively recent development, according to Dr. Molina.  Tropical Race 4 has the capacity to affect banana varieties unaffected by other Foc races.  Of immense importance is its ability to infect the Cavendish types of banana (AAA) of which the Philippines has a number of important cultivars that include “Bungulan.”  The AAB type, which also has a number of local cultivars that include “Latundan,” is said to be also susceptible.

There have been reports of Panama disease hit Cavendish bananas in the Philippines since 1980s, said Dr. Molina.  The threat then was not deemed to be on the same level of virulence as those of neighboring countries and was treated as isolated cases.

However, in the 2000s, reports of increasing susceptibility to and speed of spread of Panama disease escalated among Cavendish banana plantations in Mindanao, particularly in and around the districts of Davao City and could no longer be ignored.

“Banana is a major dollar earner of the county and any threat such as Fusarium wilt must be promptly addressed,” said Oscar Parawan, then director of Davao’s Department of Agriculture.

In the absence of an economical method to eliminate the Panama disease, the best defense is still prevention.  It has been suggested that stricter quarantine measures should be enforced particularly the setting-up of footbaths in local farms and interconnecting roads to prevent the spread of the disease.

In addition, there was a local ordinance among farmers to refrain from moving planting materials such as suckers and rhizomes out of infected areas.  It also stresses proper disposal of infected plant such as burning them within the area with rice hull.

Farm hygiene is also recommended to be strictly observed as the pathogen can attach itself on footwear, farm equipment and machinery used in an infested soil.  Cultural practices such as plowing and hoeing could also cause the spread of the pathogen.

In an editorial, “Sun Star” Davao noted: “There is no recourse but to isolate the affected land and there is no temporary solution but to turn the whole land in the hope that the heat generated will be enough to kill the pathogens in the soil.  The normal way of doing it is covering the land with rice hull to make the dried plants even more inflammable and generate more heat.  But this is not always effective.  The only recourse is to abandon the land.”

But there’s good news.  The Department of Agriculture has reportedly developed some Fusarium wilt resistant varieties.  Dr. Lourdes Generalao, president of the state-run University of Southeastern Philippines, announced that her institution is already looking into mass producing the variety. (To be concluded)