Tropical Gardening: 2016 — The year of the monkey and palms

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This is the Year of the Monkey, according to the Chinese calendar. With that in mind, the International Palm Society scheduled its biennial meeting for June 12-19 in the land of our distant relatives in Borneo.

This is the Year of the Monkey, according to the Chinese calendar. With that in mind, the International Palm Society scheduled its biennial meeting for June 12-19 in the land of our distant relatives in Borneo.

Sarawak, Borneo, is famous for its orangutans and some extremely rare palms. These simians and many palm species are threatened with extinction because of destruction of the island’s forests. There are many other primates there such as the proboscis monkey, but the orangutans — with 90 percent of the same DNA as humans — seem almost human in their behavior. Their bright orange hair, personality and expressive faces are more than cute. Some folks who work with the Borneo Orangutan Rescue Project say they feel like they are working with human children at times. The local people see them as the “old men of the forest.”

Although meeting the orangutans will be part of the biennial experience, most of the time will be spent studying palms. Perhaps new species will be discovered and brought into cultivation. Soon, they might be showing up in local botanical gardens, nurseries and home landscapes. We already have sealing wax palms and Licuala, Caryota and Pinanga species from the region here, but many more are yet to be introduced.

The IPS biennial will start in Borneo and finish in Singapore. If you are interested in a once-in-a-lifetime experience, consider exploring the jungles of Borneo with nature lovers from Hawaii and all around the world.

You can get details by checking out the IPS website. We have an active chapter of the society that meets on a regular basis on the Big Island. You can contact chapter president Mary Lock at 430-0401 for upcoming meetings, tours and program dates.

When it comes to species of palms in the world, there are thousands with more discovered each year. They come from the high mountains, such as the Andean wax palms that live at 13,000 feet above sea level, to equatorial rain forest species such as those from Borneo. Desert palms are another large group, but none is quite so close to our Hawaiian hearts as the coconut palm.

The coconut palm group is composed of scores of varieties including some dwarf types that should be used more in Hawaii. Not only are they shorter and easy to harvest, they are resistant to a devastating disease referred to as lethal yellowing.

Palms here have few serious diseases at present. Hawaii’s palms can be affected by bud rot or stem bleeding disease that often is caused by physical damage such as unsanitary pruning equipment or climbing spikes. Most palms showing yellow or stunted growth have been found to be suffering from lack of fertilizer or water. For example, a recent report came from concerned citizens calling about the sickly Fiji ivory palms (Veitchia joannis) on Henry Street mauka of Queen Kaahumanu Highway in Kailua-Kona. The trees simply need a balanced fertilizer plus minor elements, applied three to four times per year, and regular irrigation.

All these problems are correctable, but if lethal yellowing ever gets to Hawaii, there’s no practical way of stopping destruction of our island’s palms. Not only would the coconut palm be destroyed, but more than a hundred species of native and exotic palms also would die.

To realize the full potential threat of lethal yellowing, picture the streets of Waikiki and Kahala with tens of thousands of dying coconut palms in all stages of the disease, from the early brassy yellowing of the lower fronds through the collapsing of the crown and the final “telephone poling,” when there is nothing more than a naked trunk.

This disease, originally thought to be a disease exclusively of coconut palms, occurs in the West Indies, Florida, Texas, Mexico and Africa. A similar disease occurs in the Philippines.

Lethal yellowing hit Key West, Fla., in the middle 1950s. After a number of years and killing three-fourths of the coconut palms, it stopped. In the early 1970s, it was found in the Greater Miami area. Since the Jamaica tall coconut palm is planted almost exclusively in Florida, the disease ran rampant. By 1980, most coconut palms in South Florida were dead.

Research at the Coconut Industry Board in Kingston, Jamaica, showed that all varieties of coconuts are susceptible to lethal yellowing. The degree of susceptibility has been the point for developing varieties resistant to the disease. On the one end of the scale, the Jamaica tall coconut is about 100 percent susceptible. On the other end, the dwarf types are slightly susceptible. Crosses of the dwarf and tall are fairly resistant.

When lethal yellowing hit Florida, it was discovered many other palms also are susceptible to the disease in varying degrees. According to the University of Florida Lethal Yellowing Research Station in Fort Lauderdale, hundreds of other palms are susceptible, such as the Manila palm, fishtail palm, loulu palm, date palm, oil palm and many others.

Mycoplasma-like organisms, that occupy a niche between a virus and bacteria, are the cause of lethal yellowing. Mycoplasma-like cells were found in tissues of all diseased palms examined by the University of Florida scientists at the research station in Fort Lauderdale. They appeared to be transmitted by a leafhopper. Remember, neither the disease nor leafhopper have been found in Hawaii.

Florida embarked on a two-stage program to replant the stripped areas. More than half a million Malayan dwarf seed nuts from Jamaica were imported. The Malayan, while highly resistant to the disease, also has the added benefit of easily harvested nuts and does not require expensive nut and leaf removal as with the tall varieties. Florida researchers also started a hybridization project, crossing Malayan palms with Panama talls that have shown resistance to lethal yellowing in Jamaica. The resulting Maypan is highly resistant and also grows with more vigor similar to the Jamaica talls.

Today, a visitor to South Florida would not be aware of the devastation caused by lethal yellowing. Thanks to the efforts of the state and communities of Florida, International Palm Society, Florida Nursery and Growers Association and others, millions of disease-resistant palms have been planted.

Another approach for us in Hawaii is the addition to our landscapes of other palm species showing resistance to lethal yellowing. The International Palm Society and University of Florida cooperated on a project to use more palms not susceptible the disease. Resistant palms include royals, Ptychospermas, Arecastrum, Dypsis, Washingtonias, Sabals, Rhapis, Bismarkia and hundreds of others.

What is the threat of lethal yellowing to Hawaii? Transporting plants, especially palms from affected areas such as Florida, could introduce the disease.

Fortunately, seed has not been found to carry lethal yellowing. It still is essential to work with the Department of Agriculture and plant quarantine folks to have all imported plants and seed inspected. Above all, do not smuggle in plants or seed. This is how we got the spiraling whitefly, banana bunchy top disease and many other serious pests.

So, be sure to follow the rules and regulations developed to protect our islands. Also be aware that there are very stiff fines for bringing plants or animals into the Islands without the proper permits and inspection.

This information is supplied by the University of Hawaii College of Tropical Agriculture and Human Resources. For further information about gardening and landscaping, contact one of our master gardeners at 322-4892 in Kona or 981-5199 in Hilo.