Nick Carne
Biological control, where natural enemies keep insect pests at bay, is saving farmers in Asia and the Pacific billions of dollars, according to research led by Australia’s University of Queensland.
Kris Wyckhuys and colleagues reviewed the use of 75 different biological control agents against 43 pest targets over the period 1918–2018 and found they promoted rural growth and prosperity even in marginal, poorly endowed, non-rice environments.
Scientists meticulously choose co-evolved beneficial insects that are the most effective and least likely to pose ecological upsets, Wyckhuys says.
“Biological control delivered durable pest control in myriad Asia-Pacific agriculture sectors, permitting yield-loss recoveries up to 73%, 81% and 100% in cassava, banana and coconut crops respectively,” the authors write in a paper in the journal Nature Ecology and Evolution.
“The ensuing economic dividends are substantial, as pest-induced losses up to US$6.8 billion, US$4.3 billion and US$8.2 billion annually for the above crops were offset (at respective values of US$5.4-6.8 billion, US$1.4-2.2 billion and US$3.8-5.5 billion yr, for a conservative to high-impact scenario range).”
Nations such as Indonesia that prioritised biological control enjoyed productivity gains in pest-afflicted banana (1222%) and cassava (322%) far surpassing those of paddy rice (303%).
“That’s a phenomenal amount of money and benefit, particularly when compared to other innovations in the agricultural sector,” says Wyckhuys about the overall results.
“A good point of comparison is the Green Revolution in Asia during the late 1960s, which tripled the output of local rice production but also saw a rise of chemical fertilisers, agrochemicals and newer methods of cultivation.”
The researchers say their findings are consistent with a recent global synthesis that demonstrated the economic value of biological control for arthropod pest management on the basis of 44 published studies from across the globe.
However, values in the new study “dwarf those from this recent synthesis largely because they are founded on a much larger pest complex, more crops, an expansive geographic coverage and broader underlying assumptions”.
The new findings, they say, highlight that technological change and its associated productivity gains are “not exclusively due to improved genetics, mechanisation or synthesised chemicals, but also involve agro-ecological measures”.
And yet, they suggest, the discipline of biological control finds itself at a crossroads.
“As pest–natural enemy interactions are tied to global environmental change, habitat loss, agrochemical pollution and insect biodiversity decline are causing net negative impacts,” they write.
“Biological control equally suffers from declining institutional capacity, a lack of public recognition, fading attention by the [Consortium of International Agricultural Research Centres] and increasingly stringent regulations.
“Yet, modern biological control explicitly balances ecological risks with multifaceted benefits, and its judicious use can safely reduce invasive species impacts, ease vector-borne disease burden and exert stabilising effects on commodity markets.”