Fall armyworms from China invade Taiwan

First crop-destroying fall armyworms seen on the march in western Taiwan

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 (Miaoli County Agriculture Office photo)

(Miaoli County Agriculture Office photo)

TAIPEI (Taiwan News) -- The first fall armyworms (FAW) to be detected in Taiwan have been spotted at a popular tourist ranch in western Taiwan on Saturday (June 8), after plum rains apparently blew them in from China, which is suffering a devastating outbreak of the ravenous larva.

On Saturday afternoon, tourists spotted what they suspected were fall armyworms feasting on corn stalks at the Flying Cow Ranch in Miaoli County's Tongxiao Township, reported News&Market. According to Tsai Cheng-hsin (蔡政新) head of the Miaoli County Agriculture Office's Agricultural Services Division, "More than ten fall armyworms crawled on the green cut corn planted in the pasture mainly to enable tourists to experience feeding cattle."

Miaoli County officials then rushed to the spot to collect samples and sent them to nearby university in the evening to carry out morphological and molecular identification. The Council of Agriculture (COA) used molecular technology to sequence the genes of the specimens and they were confirmed to be fall armyworms.


(Miaoli County Agriculture Office photo)

At a press conference on Monday (June 10), the COA announced that the analysis confirmed that the caterpillars found in Miaoli were indeed fall armyworms. During the press conference, Feng Hai-tung (馮海東), head of the COA's Bureau of Animal and Plant Health Inspection and Quarantine said that unchecked, the fall armyworms could devour as much as 20 to 30 percent of Taiwan's wheat, corn, sorghum, and rice crops and hinder 45 percent of the cultivation of those crops, reported CNA.

COA Deputy Minister Huang Chin-cheng (黃金城) speculated that southwesterly winds may have blown the prodigious moths from southeast China to western Taiwan. The Bureau of Animal and Plant Health Inspection and Quarantine (BAPHIQ) has announced the 11 kinds of pesticides, including Neem oil and Bacillus thuningiensis, which can be sprayed on corn, rice, and sorghum to fend off the FAW.

The government has now placed 500 traps using pheromones in airports and seaports to try an monitor the movements of the creatures. Huang said that because this is likely the first generation of fall armyworms and they are still in their larval stage, it is imperative that they are dealt with immediately, before they transform into moths and spread throughout the country.


First fall armyworm spotted at Flying Cow Ranch. (Miaoli County Agriculture Office photo)

The fall armyworm, which looks similar to the tobacco cutworm, but is a more serious threat, has recently caused large-scale damage in China, Africa, and South Asia. According to the BAPHIQ, a single FAW can produce 1,500-2,000 eggs in a lifetime, and the adults are very good at flying, up to 100 kilometers in a night.

In January of this year, the invasive species was first reported in Yunan, China and has thus far infested 18 provinces, including 92,000 hectares of farmland, mostly affecting corn and sugarcane crops, reported the New York Times. Experts had been concerned that because the moths can fly up to 100 kilometers in one night, and as southwest winds blow in with the plum rain season from China, they would soon establish themselves in Taiwan. Those fears appear to have been realized.

The distance between China and Taiwan is very short in certain areas, such as Kinmen, which is only a few kilometers away from Xiamen in Fujian Province. Officials worry that large swaths of sorghum crops could first bear the brunt of the assault from the voracious caterpillars.


Feng pointing out areas infested by FAW in China. (CNA photo)

A native of tropical and subtropical areas of the Americas, FAW spread to Africa in 2016, where it wrought devastation across the continent. In 2017, it spread across Asia, including Yemen, India, Bangladesh, Myanmar, Thailand, and Sri Lanka.

Chiang Ming-yao (江明耀), an assistant researcher at the Taiwan Agricultural Research Institute, told News & Market that the official scientific name of the fall armyworm is (Spodoptera frugiperda), which is a species in the order of Lepidoptera. Chiang said that it is similar to the tobacco cutworm, which endangers vegetables.

He said that its larvae and adults (moths) are similar in length and evolve from eggs to larvae, to pupae, and finally to adult moths. Chiang said that although the FAW and tobacco cutworms are similar in appearance, the FAW's head capsule is brown and has an inverted Y-shaped yellow marking on it.


Damaged inflicted by armyworms on corn stalk. (Miaoli County Agriculture Office photo)

The back of the FAW's eighth abdominal segment has four black dots that form a square pattern. In contrast, the head capsule of the tobacco cutworm has a white mark on it and its eighth abdominal segment has only two black dots.

FAW females prefer to lay their eggs on gramineous crops such as corn, wheat, sorghum, rice, and taro. The larvae born on these crops will feed off of them and inflict significant damage. As Taiwan has a small-scale farming economy with a wide variety of crops mixed in close proximity to each other, measures will need to be taken to fend off the omnivorous caterpillars from all non-aquatic crops.


Crops being destroyed after FAW confirmed. (Miaoli County Agriculture Office photo)


Life cycle of fall armyworm. (Council of Agriculture, Executive Yuan photos)