PEST attacks have been wreaking havoc on plants in a mangrove nature reserve in Futian District.
More than 3,330 square meters of "Avicennia marina" mangrove trees have withered after attacks from pests bearing the same name as the tree variety, the Daily Sunshine reported yesterday.
Reserve engineer Yang Xinlin said Avicennia marina pests attack their namesake trees from about June to September every year. Yang said trees that have withered still have complete trunks, which means they will sprout again.
Five experts from the insect research institution of Sun Yat-Sen University noticed increasing pest attacks in the reserve in the 1990s, the paper said. The experts said Avicennia marina trees won’t blossom or breed seedlings after an extended period of pest attacks.
The severest danger to the reserve's mangroves, though, is a different pest that falls like a snowflake. Such an attack broke out earlier this month and will last three months, Yang said.
A brown pest, seen everywhere in the reserve, spits a liquid onto leaves to screen them from sunlight. Trees' growth is stunted as a result, reserve administrator Zhang Ziru said.
The brown pest usually lives between 50 and 70 days before dying in autumn.
The reserve's management body has been struggling to prevent the pest attacks, but no positive results have yet been achieved.
"We spent 300,000 yuan (US$47,615) on research in cooperation with scientific and technological institutions, using their biological agent. However, the agent has not worked well," Yang said.
Chemical agents are used to kill pests in the reserve without harming birds or fish.
Experts said the reserve's prevalence of pests is a result of its decreasing number of the pests’ natural enemies, including birds, and an overall deterioration of its ecosystem.
The reserve has seen a sharp decrease in the number and diversity of land birds, the paper said, citing expert investigations.
By Zhang Qian, Martin Li, Shenzhen Daily