Invasive crazy ants threaten Christmas Island Red Crab populations, but a certain species of wasp might be able to help.
Christmas Island, a remote Australian territory in the Indian Ocean, is known for an abundance of Red Crabs, a species once recorded in numbers nearing 44 million. The Red Crab has captured the hearts of naturalists and nature novices alike, due to the beauty and magnificence of their yearly mass migration from land to sea to lay their eggs in the ocean. However, in recent years, they have suffered a tremendous decline of roughly 40 million, according to recent population surveys. The cause? Invasive crazy ants, which are believed to have been introduced by a ship sometime during the early 20th century.
Used as an effective method of controlling invasive species, biological control (or biocontrol) is the term given to the use of living organisms for controlling pests and invasive species. It can provide an effective, environmentally-friendly and cost-efficient way of controlling pest populations, helping to restore crop yields and farmer’s profits. However a recent study, focussing on invasive cassava mealybugs, has shown that biocontrol can also have some surprising knock-on effects.
Parthenium hysterophorus is a highly destructive weed which has invaded and is widespread in around 48 countries in Africa, Asia, and the South Pacific. In Pakistan the weed is spreading rapidly westwards and southwards across both rural and urban landscapes, affecting native ecology and harming agriculture.
Invasive species pose a serious threat to food security, biodiversity, water resources, human and animal health, and economic development. It is widely acknowledged that integrated control is the most effective strategy in managing invasive plants where it involves the use of herbicides, manual or mechanical control, and biological control agents in an integrated way. Last month, a short course on invasion biology and classical biological control of weeds was delivered at CABI in Pakistan.
CABI scientists have made the first discovery of the Asian samurai wasp Trissolcus japonicus – a natural enemy that kills the eggs of the the invasive fruit and nut pest brown marmorated stink bug (Halyomorpha halys) – in Europe.
Judith Stahl and Dr Tim Haye led an international team of researchers, including those from the University of Turin and the USDA Agricultural Research Service, who used DNA analysis to confirm the wasp – which is native to China, Japan and Korea – was found in Switzerland in 2017.
A major new report published by CABI has today revealed that losses due to fall armyworm are lower than projected in 2017 and the pest is still primarily focussed on maize rather than any other potential host crops. Better monitoring, swift responses by governments and farmers and an increase of natural enemies attacking the pest all help in mitigating the devastating crop losses it can cause.