The Canarian Institute of Agricultural Research (ICIA) is investigating the potential of ‘Acerophagus utilis’, a parasitoid insect successfully used in Hawaii over a century ago, as a biological control method for avocado scale in the Canary Islands.
This research was presented on Wednesday at the III Scientific Avocado Conference held in Valle de Guerra, Tenerife. The ICIA shared its progress on improving the productivity, adaptability, and health of avocado crops, according to a statement from the Canarian government.
For several years, the institute has tested natural enemies to diminish populations of the ‘Nipaecoccus nipae’ scale, but none of the studied alternatives have consistently reduced the pest significantly.
One such alternative, the lacewing ‘Chrysoperla carnea’, showed some success with fortnightly releases reducing scale numbers in spring. However, the scale returned to high levels by autumn.
In light of these findings, last year the ICIA began exploring a classical biological control programme using ‘Acerophagus utilis’, which was introduced from Mexico to Hawaii in 1922 specifically to combat this pest.
Historical records indicate that within two years of its introduction, the scale was nearly eradicated, with complete removal confirmed by 1926 in that region. There are also reports of successful use of the parasitoid in Puerto Rico and other Caribbean islands.
Estrella Hernández Suárez, a researcher at ICIA, noted that the extensive information gathered over nearly a century about the parasitoid’s biology and behaviour allows for a careful evaluation of its safety, specificity, and effectiveness before considering its use in the Canary Islands.
To support this research, the ICIA has established contacts with institutions including the Natural History Museum in London, the University of Florida, and scientific teams in Hawaii and Mexico.
In September, the ICIA conducted an initial survey in Florida to collect various species of parasitoids, with another campaign scheduled for December in Hawaii to verify if ‘Acerophagus utilis’ is still present in areas where it historically interacted with the scale.
The Canarian government’s Agriculture Advisor, Narvay Quintero, underscored the need to find tools that reduce reliance on phytosanitary treatments and effectively combat pests affecting the islands’ crucial crops.
