Local folks and visitors often think our islands have few dangers except for rare volcanic eruptions, earthquakes and hurricanes. ADVERTISING Local folks and visitors often think our islands have few dangers except for rare volcanic eruptions, earthquakes and hurricanes. Excessive
Local folks and visitors often think our islands have few dangers except for rare volcanic eruptions, earthquakes and hurricanes.
Excessive exposure to the sun can be dangerous, and people drown every year by being careless at the beach or hiking in the mountains. Although there are few poisonous native plants, some common exotic landscape plants are toxic such as oleander, crotons and angel trumpets. Some people can experience skin reactions like exposure to poison ivy from cashew and mango trees.
When it comes to animals, most folks don’t know we have a very poisonous native snake. The yellow-bellied sea snake is found throughout the tropical Pacific, including in Hawaii. Then there are the giant Bufo toads that some people confuse with bullfrogs. The toad’s skin is toxic, so eating them is bad news.
We also have a cute green and black poison dart frog on Oahu. It is not a good idea to play with them.
There is another kind of peril that isn’t quite as obvious. It’s the destruction to our environment by accidentally introducing diseases and pests. Many of the plant diseases we have here today did not exist before humans arrived.
Once here, they are not easy to control. The best disease prevention measure you can take with ornamental plants, fruits and vegetables is to start with healthy or disease-resistant plants.
A common fungus referred to as plumeria rust is showing up on many garden plumerias now. The disease is relatively new to Hawaii. Symptoms show up as a rusty appearance on the underside of leaves. This causes premature yellowing and dying of leaves.
According to University of Hawaii plant pathologists, once a plant becomes badly diseased, it is difficult to nurse back to health. For this reason, every effort should be made to prevent introduction of disease-causing organisms on plant material or in soil.
Many common plant diseases are caused by fungi. Others are caused by viruses and bacteria. Identifying the cause is vital to knowing the proper cure.
Plants in poor growth usually are more susceptible to these diseases. Good cultural and sanitation practices including removing diseased parts such as leaves or branches as soon as they appear affected will help prevent trouble. Treat pruning wounds with a specially prepared material to stop entrance of wood-decaying organisms and wood-feeding insects.
For treatment of fungus diseased plants, fungicide applications should begin when disease development first appears and should continue as recommended by the manufacturer.
Algae commonly grow on the surface of soil that is moist for periods of time. This is very common during the rainy season. These minute green plants often develop in such profusion that they form a rather thick, greenish to blackish mat.
Growth of such magnitude in a turf planting is detrimental to the grass because algae actively compete with the grass for space and nutrients. In addition, if the algae mat dries it forms a crust that retards or prevents the movement of water into the soil. If this occurs, the grass is subjected to a moisture stress directly because of the presence of the algae.
The same conditions that favor the growth of algae also favor the growth of fungi that cause turf grass diseases. In fact, a close association has been noted between frequent disease outbreaks and the presence of algae. Therefore, it’s desirable to control both of these problems with one practice.
Reducing the moisture level would be the ideal method; however, in many situations, this is not possible. Other control measures must be used. The use of fungicides effective against turf diseases and algae is an efficient method of control. Your local garden supply or nursery can assist you with the correct material to use.
You also can call the Master Gardener hotline at the University of Hawaii College of Tropical Agriculture and Human Resources. In Hilo, the main number is 981-5199. In Kona, the main number is 322-4892. You then can be directed to Extension staff or Master Gardeners to assist you.
Bacteria, fungus and algae are not always harmful. Our edible limu is an alga, yogurt is the result of a certain type of bacteria and those delicious mushrooms on your steak are a fungus. These beneficial organisms are important to a healthy soil, and to healthy nutrition. Many that are yet to be discovered could be key in developing new drugs to fight disease in plants, animals and humans.
However, prevention of disease-causing organisms is vital.
Some folks get unhappy when they find they can’t bring certain plants or seeds into Hawaii, or if they can, they have to go through all kinds of red tape, fumigation or extended quarantines.
A few of these folks figure it is a bother to get permits and go through the proper procedures. They smuggle a few plants thinking it won’t make any difference. This attitude couldn’t be further from the truth or more dangerous.
If it weren’t for people bringing in disease- and insect-infested plant materials, our island would not be plagued with such creatures as fruit flies, burrowing nematodes and many other pests that damage food crops as well as ornamentals. Just the fact that we are plagued by fruit flies means the potential export of mangoes and other tropical fruits is nipped in the bud. So, we lose millions of dollars of potential income because of some careless person who didn’t think it would hurt to smuggle in some fruit.
Now, there are serious fines and even imprisonment for plant or animal smuggling. This should discourage potential pest introductions.
Florida has one of the best examples of what happens when people get careless about clean plant introductions.
Lethal yellowing, a disease of palms, killed palms by the tens of thousands there and is a threat to other areas such as Hawaii. The disease affects coconut palms, Manila palms and Hawaiian fan palms. If lethal yellowing arrived here by importing infected plants, our native palm species would soon be extinct.
According to the University of Florida, the disease has been reported in the Dominican Republic, Bahamas, Cuba, other Caribbean islands, Venezuela, Panama and West Africa. It was identified in Key West in 1955 and ultimately spread throughout South Florida.
The disease, similar to a virus, is a mycoplasma that infects the plant. Taking palms from infested areas to an area free of lethal yellowing is extremely dangerous. A leafhopper is involved in spreading this palm plague. Florida lost at least 90 percent of its coconut palms, but fortunately, coconut palms resistant to the disease replaced those lost. The cost of the infestation ran into hundreds of million of dollars.
This, again, shows we should support our state and federal agricultural quarantines. Importing plants illegally could bring a devastating disease such as this to Hawaii.
There are ways to bring in new plants to Hawaii legally. The state Department of Agriculture and USDA Plant Quarantine Office can give you details.
By following the law, hundreds of new plant introductions are being made each year. These can enrich our lives without bringing with them unwanted insects and diseases that could bring disaster to our economy.
