Invasive alien species are a headache for scientists trying to find ways to eradicate them.

Mimosa pudica (scientific name)Mimosa pigra) or alsocalled mimosa pudica, cat's eye, mimosa pudica, native to Central America and South America. This weed is ranked as the 3rd most dangerous in the world and is on the list of 100 most dangerous pests for most countries, due to its ability to spread quickly, seeds can germinate after 20 years, burning, leveling still grows back.

Introduced to Vietnam since 1960, the Mimosa tree has now spread to many localities throughout the country. It grows well on hillsides, sandy soils and wetlands. The areas where the Mimosa tree grows have no competition from any other tree.

Survey by Associate Professor Nguyen Hong Son, Vietnam Academy of Agricultural Sciencesshows theIn the semi-flooded areas of the Mekong Delta, hydroelectric reservoirs such as Tri An, Thac Ba, Hoa Binh..., mimosa trees grow densely, forming large belts.

In Lam Dong, there are nearly 200 hectares of mimosa trees scattered along the banks of the Da Nhim River. Every year, the locality has to spend hundreds of millions of dong from the budget to treat mimosa trees.

In the La Nga River area (Dong Nai), this tree also occupies a large area of ​​agricultural land. Before each planting season, they have to spend nearly 2 million VND to cut and burn the mimosa trees.

Up to this point, no agency has found a way to completely eradicate this invasive plant species.

Inject medicine into the body to kill yellow morning glory

Morning glory (scientific name is Merremia boisiana) belongs to the Morning Glory family. The plant looks like sweet potato leaves so some people call it wild sweet potato or silver leaf plant. The plant is a climbing plant, with a woody stem up to 8cm in diameter, climbing about 10m high so it can take up all the light, killing the plants below.

According to Associate Professor Tran Dinh Hoe, Vietnam Association for Conservation of Nature and Environment, this climbing plant originates from the tropical climate of Hainan Island and the Zhuang Autonomous Region (Guangxi, China), and is called Jinzhongteng or Assassin Tree.

The plant spreads very quickly by seeds, shoots, roots and stems. The Morning Glory plant entered our country about several decades ago, growing at the foot of Hai Van Pass. To date, scientists have discovered that in Vietnam, the Morning Glory genus has up to 17 species and 3 varieties.

The species of Morning Glory has appeared in Sa Pa (Lao Cai), Lang Son, Quang Ninh, Bach Ma National Park, Nam Dong (Thua Thien-Hue), the high altitudes of Son Tra and Ba Na nature reserves (Da Nang)...

Localities have spent a lot of money to eradicate this tree but it has not been effective. Recently, Quang Binh has planned to test eradication on 100 hectares in the service - administrative subdivision.

The Institute of Agricultural Environment also conducted a state-level research project to find a solution to prevent the growth of morning glory by injecting herbicides into the trunks of mature plants.

The pesticide will penetrate the tree in about 30-40 minutes. After 20 days, the leaves will turn yellow and the tree will gradually die. After three to six months, the tree will die completely, depending on the diameter of the trunk. This method has been successfully tested and modeled in Da Nang.

People are in trouble because of golden apple snails

The golden apple snail is one of the most destructive pests in Vietnam. This species was introduced into Vietnam before 1975 for ornamental purposes. In 1989, two golden apple snail farms were established in Cu Chi, Ho Chi Minh City to breed and export golden apple snails. In 1990, experimental farming of golden apple snails began in the North of Vietnam.

The golden apple snail then spread rapidly along the water bodies and has now been recorded in most regions in Vietnam. They can lay eggs everywhere, clinging to tree branches, blades of grass, and even laying eggs on brick and stone slopes.

Their food is mostly plants so they pose a serious threat to biodiversity as well as agricultural production.

For many years, people have had to use measures such as catching, spreading lime powder, and spraying pesticides to limit the invasion of golden apple snails, but they have not been really effective.

Besides, there are many alien species such as beaver, black mink, pentacolor plant, water hyacinth... that have made both management agencies and people miserable because it is difficult to find measures to prevent their development.

According to experts, Vietnam needs to thoroughly and strictly apply quarantine measures and proactively prevent the spread of alien species. These are species that threaten people's livelihoods and agriculture.