Double-warted glass ants invade in force as the infestation worsens; experts suggest sugar baiting to lure and kill them
August 25, 2016 news update: The two-warty glass ant (also known as the warty-chested glass ant) has become a plague and continues to spread in Nantou, including Zhongliao, Mingjian, Guoxing, Puli, Shuili, Jiji and other places, where residents are overwhelmed by the nuisance. The following is a June 2016 report that provides expert solutions.
Thousands of two-warty glass ants attack; feed them sugar to lure and kill the enemy
Recently, the Jiji area of Nantou and the Xihu area of Miaoli have been severely troubled by two-warty glass ants. Each time these ants appear, there are as many as thousands of them. They swarm in groups along water pipes and electrical wires into houses. No matter how much insecticide is sprayed or how much fire is used, it is useless. Biological experts remind that this type of glass ant has huge colony numbers, and usually only 30% go out to forage. Therefore, by setting bait and adding 3% low-toxicity boric acid to 20% concentration sugar water, inducing the glass ants to feed and carry it back to share with their companions, it is possible to reduce the overall colony numbers.
Insecticides and fire attacks are useless; sugar baiting works
The two-warty glass ant belongs to a multi-queen colony. "Usually, when an ant nest reaches tens of thousands of ants, there will probably be hundreds of queens," pointed out Lin Tsung-chi. Generally speaking, in an ant nest, mostly only 30% of the worker ants go out to forage, and the remaining 70% reproduce inside the nest. Therefore, traditional spraying of insecticides, applying environmental pesticides, or even fire attacks can only kill the worker ants in front of you, while the nests behind them still keep coming endlessly. It treats the symptoms but not the root cause.
The best way to reduce two-warty glass ant colonies is to set "bait." Two-warty glass ants love sugar, mainly feeding on plant nectaries or the honeydew secreted by hemipteran insects such as aphids and scale insects. Because they also have the characteristic of trophallaxis, that is, after feeding, they first store part of the food in their stomach and carry it back to the nest to share with other companions.
Lin Tsung-chi suggested that if large numbers of two-warty glass ants appear in a home or orchard, a bait can be made by mixing 3% low-toxicity boric acid with 20% sucrose water to attract the glass ants to feed, so that worker ants may carry it back to the nest and cause more glass ants to die. He reminded that the sugar water concentration must not be too high, and about 20% is recommended, because if the bait is too sweet, or even gelatinous, the two-warty glass ants will not eat it.
Lin Tsung-chi especially reminded that if people want to set bait in their homes, it is best to label it clearly to prevent others or children from eating it by mistake.
Clean the home environment and diligently prevent scale insects in farms to reduce the possibility of invasion
In addition, the reason two-warty glass ants invade homes is that they want food and water. Besides setting bait, environmental management is also very important. Lin Tsung-chi said that the outer surroundings of homes near shallow mountain areas often have discarded items such as bamboo poles and water pipes, and even melon sheds and melon trellises are built next to farmhouses. These structures are places where two-warty glass ants especially love to hide and climb. Trying to clear these facilities helps block the invasion of glass ants.
If large numbers of two-warty glass ants infest orchards or bamboo forests, the Tainan District Agricultural Research and Extension Station of the Council of Agriculture suggests starting with daily environmental cleanup and the control of scale insects, which have a symbiotic relationship with two-warty glass ants.
Last year, the Tainan Agricultural Research and Extension Station carried out two-warty glass ant control work in orchards in the Zhuqi area of Chiayi. They found that, compared with conventional orchards, eco-friendly cultivated orchards that do not spray pesticides had larger colony numbers. In particular, orchards that had not been weeded or pruned for a long time were even more troublesome. Therefore, increasing human disturbance and using biological materials to control scale insects is the first step to reducing two-warty glass ant infestation.
Expert: Full eradication is difficult; learning to coexist with them is worth noting
It is worth noting that both domestic glass ant expert Lin Tsung-chi and Huang Te-chang, Director-General of the Bureau of Animal and Plant Health Inspection and Quarantine of the Council of Agriculture, mentioned that the two-warty glass ant is a native species and is very difficult to completely eradicate. It depends on ecological balance to gradually return the colony to normal numbers. Therefore, "the public must overturn the past mentality of full eradication and try to recognize that the two-warty glass ant is part of the environment."
Lin Tsung-chi said that ant species such as the big-headed ant and the Huangshan ant are active in shallow mountain areas but will not enter homes, instead building nests near residences. Such ant species are more capable of competing with the two-warty glass ant. He suggested that the public should spend more effort understanding the characteristics of living organisms.