It is a fine day for a drive wherever you live on our beautiful island. Rain or shine, your drive should include Panaewa Rainforest Zoo and Gardens. This hidden gem in the emerald rainforests near Hilo is home to tigers, macaws and all kinds of wildlife. It is also known for the great collections of palms, bamboos, cycads and tropical rhododendrons. Today, there is a big plant sale from 8 a.m. to 2 p.m. with around 20 vendors. Hawaii Island Palm Society will be giving away rare palm seed and at noon Tim Brian will lead a palm tour. Even if you live on the Kona side, it is a beautiful drive to view all the spring flowering trees like ohia, jacaranda, silver oak and African tulips along the way.
The zoo sale will also give you an opportunity to meet knowledgeable horticulturists including enthusiastic members of the society who enjoy sharing their plant growing experiences. Of course, they will encourage you to become a member and that is a good thing. The society supports research, conservation and discovering new species throughout the world. They have biennial meetings for members in exotic places like last year’s meeting in Borneo. Next year the meeting will be in Colombia. On these trips much of the time is spent studying palms. Perhaps new species will be discovered and brought into cultivation. Soon they may be showing up in local botanical gardens, nurseries and home landscapes. We already have species from tropical Asia, Africa and the Americas, as well, but many more are yet to be introduced. If you are interested in a once-in-a-lifetime experience, consider exploring the jungles of South America with nature lovers from Hawaii and all over the world. You may get details by checking out the IPS website at International Palm Society. The Hawaii chapter meets on a regular basis. You may contact 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 like the Andean Wax Palms that live at 13,000 feet above sea level to equatorial rainforest species like those from the Amazon. 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 may be affected by bud rot or stem bleeding disease that is often 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 dead and dying trees around 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 in Hawaii, there’s no practical way of stopping destruction of our island’s palms. Not only would the coconut palm be destroyed, but over 100 species of native and exotic palms would also 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 exclusive to coconut palms, occurs in the West Indies, Florida, Texas, Mexico and Africa. A similar disease occurs in the Philippines.
Lethal yellowing hit Key West, Florida, in the middle 1950s. After a number of years and killing three-quarters of the coconut palms, it stopped. In the early 1970s, it was found in the Miami area. Since the Jamaica tall coconut palms is the one that had been 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 Jamaica showed that all varieties of coconuts are susceptible to lethal yellowing. The degree of susceptibility has been the point for developing varieties that are resistant. On the one end of the scale, the Jamaica tall coconut is about fully 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 that many other palms were also 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 like 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 of a million Malayan dwarf seed nuts from Jamaica were imported. The Malayan, while highly resistant to the disease, also had the added benefit of easily harvested nuts and did 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.
Hawaii is fortunate to be far from disease-affected regions, but it is vital that we don’t introduce this and other plant plagues. It is important to cooperate with the Hawaii and federal departments of agriculture and follow all the rules of inspection.