每日跟讀#549: Beating back the worms: intravenous injections for trees
National Central University (NCU) has set aside an annual budget for regular treatment to deal with the “pine wood nematode” worm invasion that attacks the 1,500 pine trees on the campus. As part of this treatment, the trees are given an intravenous drip, with the medicine being injected into their trunks.
According to the university, the worms, transmitted into the branches of the trees by insects, cause the leaves to wilt and die. Agricultural experts advise the use of a “trunk injection,” which infuses the medicine into the trunk, and from there throughout the entire tree. This process can take three to four months for the agent to take effect.
Last year, some of the coral trees — which are indigenous to Taiwan — along the streets in Taichung were harmed by Quadrastichus erythrinae, an exotic wasp species. National Chung Hsing University’s (NCHU) Plant Teaching Hospital launched a rescue operation, opting for trunk injections instead of the traditional spraying approach. As a result, 133 dying trees were brought back to life.
Plant Teaching Hospital director Tang Li-cheng said that, in the past, spraying was the only option available, but the chemicals stayed on the surface of the leaves and would not penetrate into the diseased tissue. As a result, the treatment was mostly ineffective.
The “plant doctors” at the hospital now use a more precise, targeted method, applying trunk injections to infuse the medicine into the trunk through a borehole. After this, through capillary action, the medication is transported to the infected leaves by water absorbed by the tree. Tang compared it to treating a sick person: applying ointment on the skin has limited effect, while injecting the drug into the blood vessels allows it to be absorbed more efficiently.
Tang says that two doses are sufficient for a whole year for trees with a diameter an adult can put their arms around. In addition, the treatment is inexpensive and does not carry the risks associated with pesticide spraying, such as harming non-targeted plants or creatures, or even people out for a stroll in the park.
Source article: http://www.taipeitimes.com/News/lang/archives/2019/03/06/2003710907