Managing moko, a major disease affecting Cavendish bananas, has been the focus of growers, scientists, economists, and theorists for years. For one thing, the economic impact of Moko can be disastrous. There are instances when small growers (those who cultivate 3 to 5 hectares) have sustained as high as 70 to 80 percent plant losses due to Moko. But what is worse is the frustration that they have to bear when the disease reoccur.
But how does Moko occur in the first place? First of all, the casual organism of Moko is the bacterium Ralstonia(formerly Pseudomonas) solanacearum. It is a variety of bacteria that is highly infective and easily transmitted mechanically by insects or through soil particle movement. Usually the spread of disease happens when farm workers neglect to disinfect their tools before they work from one area to another.
The pathogen can thrive and remain dormant for many months in the soil until it gets in contact with the roots of a host and resume activity whent the environment becomes favorable. The pathogen also causes bugtok or tibagnol in fruits of Cardaba, and Latundan bananas.
Early symptoms of Moko include the breaking of the leaves at the petiole due to partial wilting and loss of turgidity. This always starts with one or two of the youngest leaves. The leaf breakage then progresses to the older ones until if unchecked the whole plant collapses. There is also a brownish discoloration in the bracts and in the vascular bundles of the midrib of the plant.
MANAGING THE DISEASE
In the 1970s, commercial plantations managed Moko by extensively using chemical disinfectants such as ethylene dibromide (EDB), and by applying prophylaxis procedures, localized quarantine, and long fallow periods. Other less toxic chemicals were later tried, but due to environmental concerns, control processes have eventually evolved into the current system of burning infected plants.
For each case, a minimum of 25 bags of rice hulls is used in the burning. The affected area is cordoned off with bamboo and twine to prevent access to it. The area is then laid fallow for six to eight months before it is replanted with seedlings.
As a further preventive measure, workers are required to disinfect their tools after working in each hill. Despite these precautions, the disease reoccur and pose serious economic threats.
EM APPLICATION
There is now a new and effective way of controlling Moko. It is the Effective Microorganism (EM) application.
With this practice, replanting can be done immediately after eradication if ever it was performed provided that before planting the seedlings, the newly dug planting holes are drenched with EM solution or EM compost. This is done by applying the solution or compost into the bottom of the holes. Fallow time need not be lost.
EM was commercially introduced in 1980s by Professor Teruo Higa of the University of Ryukyus in Okinawa, Japan. According to the manual for the member-countries of the Asia-Pacific Natural Agriculture Network (APNAN), there are five major groups of micro-organisms in EM and these are the following: phototrophic or photosynthetic bacteria, lactic acid bacteria, yeasts, actinomycetes, and fermenting fungi. Each one has different beneficial functions in the soil.
EM comes in liquid form; the micro-organisms are alive but inactive in sealed containers. There are a number of ways to activate EM. For Moko control, this is done by dissolving 1 liter of molasses in 1 gallon of water. Next, add 1 liter EMI (pure) then add water to make a total of 28 liters of waters or a total of 30 liters solution.
Allow the mixture to ferment anaerobically in a sealed plastic container and store it under shade at room temperature for five to ten days. The solution is called “EMAS” or EM Activated Solution, but in other literatures, it is called “AFM” or Activated FM.
Further dilute EMAS in clean water at a proportion of one part EMAS to five parts water (1:5). Then apply it to the funnel-like portion of each leaf petiole and suckers of infected plants. Cover the plant base with 5 kilos of EM compost, then drenched with a solution of one part EMAS to 20 parts water (1:20), using about 0.5 liter to 1 liter per mat depending on its size.
EM compost is made by first mixing one part EMAS to 10 parts plain water (1:10). Next, the substrate is prepared by mixing the following substrate: 40 percent chopped rejected bananas, 20 percent cow or hog manure, 20 percent saw dust or rice hull, and 20 percent rice bran.
Chicken manure can be a substitute for cow or hog manure, coir dust for saw dust, and other sources of carbohydrates for rice bran. Other organic materials such as lime, guano, NutriSmart, can also be added in the range of 1 to 5 percent.
While mixing the substrate, incorporate the expanded EMAS solution (1:20), making the moisture 30 to 60 percent. The mixture is piled less than 1 meter high, about 1.5 meters wide, and as long as required. And lastly, it is covered with plastic sheets or sacks. The temperature in the pile should not exceed 40°C. Turn over the compost every day or every other day so as not to kill the micro-organisms.
Some literatures say that the EM compost is ready for use in less than a week, while others say it takes three to four weeks. As for me, I apply my compost in less than two weeks because I have a large area to cover. And besides, I am now using the procedure for prevention, rather than for cure.
The positive effect of treating infected plants with EM starts to show when the youngest leaf resumes growth. This can be noticed within one month from initial application. In my experience, 24 infected plants were initially treated in October 21-27, 2007 (week 43 of 2007). Three plants were beyond recovery and eventually died in less than a month after first treatment. As of this writing (week 10 of 2008), it has been 19 weeks since the initial treatment. Four bunches have already been harvested and two other plants are bearing bunches of pre-harvest age. The rest (15 other plants) are on different stages of vegetative growth. However, in weeks 4 and 5 of 2008, four new cases in different locations occurred.
Mario Yoshida, who has a farm in Cadalian, is also applying EM. Actually, he was the first farmer who successfully used the EM application as a control for Moko on a commercial scale in May 2006. Then in 2007, Rolando Bahaya, who owns farms in Subasta and Wangan, both in Calinan, Davao City, and other banana farmers followed suit. They applied EM solution directly to the infected plant and spread EM compost around the base.
It is encouraging, indeed, to find about 90 percent of infected plants recovering from Moko and producing exportable fruits and healthy suckers for the next crop. Bahaya explains that Moko infection can be compared to cancer. About 10 percent of infected plants that eventually died are those that have reached stage 4. And if treatment is given early (stage 1 or 2), infected plants recover completely.
Yoshida, on the other hand, is convinced that EM could be used also as a control for Fusarium (Panama) wilt and Sigatoka. He uses EM as an alternative to systemic fungicides for Sigatoka.
WHY EM CONTROL MOKO
Why does EM control Moko? I am still not sure of the answer to this question.
In searching of an answer, I have read articles and surfed the internet. I have come across the term “competitive exclusion”. It is “the rapid multiplication of the beneficial microorganisms in EM” that possibly crowds the Moko pathogen or leaves little or no more-food for the pathogenic bacteria to survive on. My rationalization is that EM provides some ingredient(s) to the banana plant and by doing so, EM strengthens the plant’s vigor until the bacteria cannot harm it anymore.
On the other hand, Dr. Anacleto M. Pedrosa, Jr. a veteran scientist, says that microorganisms produce enzymes and metabolites, and it is possible that one or a combination of these substances might be toxic to the pathogen thus, keep the bacteria at bay. Although these are highly possible and logical explanations, these are not yet scientifically proven.
Sooner or later, scientists will come up with the explanation. But in the meantime, for those who have tried this new-found treatment, it is so far the best option in terms of cost, time, and morale.
