The main challenge related to controlling an infestation of mealybugs is the fact that eggs, young nymphs, and even adults in many cases are all encased in wax-like fluffy substance that is essentially waterproof.(1) Mealybugs cannot easily be washed away, nor can they always be properly targeted with pesticides, because the adults like to embed themselves in plant folds and pockets.
A better plan for mealybugs is to use what’s called a systemic insecticide. These types of products target not the insect itself but rather the plants that the insects feed on. Direct contact insecticides if used must be applied multiple times, while those gardeners and plant owners lucky enough to discover a mealybug infestation early on can actually wipe the leaves clean with alcohol or a standard nail polish remover.
In the summer of 2011, farmers in the southern Australian region of Riverland were confronted with one of the worst mealybug infestations in years, proving that these pests can sometimes spread despite the common control practices of commercial farming.(2) Up to 80% of oranges farmed for shipment to India and Japan were rejected because of mealybug infestation, a huge jump from the normal annual harvest discard rate of about ten percent.
One of the most intriguing methods of controlling mealybugs was deployed on the African continent in the early 1990s, helping the scientist who pioneered the effort win a 1995 World Food Prize.(3) Swiss insect expert Rudolf Hessen arranged for swarms of the bug’s predator enemy, a certain type of wasp, from airplanes flying above the fields of cassava plants.
At the time, all sorts of other attempts had been made to control the mealybug infestation, which had remained unchecked for a decade. His non-chemical solution was the first one to work, and he became the first and so far only Swiss person to win the prestigious World Food Prize. Part of the reason the mealybug spread so fast in this African case was that it was not native to the continent, and therefore had no natural enemies present. The accomplishments of Hessen were celebrated anew in the summer of 2011 via a documentary on Swiss TV.
(1) North Carolina State University – Mealybugs, Retrieved July 17, 2011 from http://www.ces.ncsu.edu/depts/ent/notes/O&T/flowers/note19/note19.html
(2) Australian Broadcasting Corporation – “Mealybugs Mangle Riverland Citrus”, June 29, 2011, Retrieved July 17, 2011 from http://www.abc.net.au/rural/news/content/201106/s3256396.htm
(3) Swiss Info – “How a Swiss Scientist Saved 20 Million People”, July 11, 2011, Retrieved July 17, 2011 from http://www.swissinfo.ch/eng/science_technology/How_a_Swiss_scientist_saved_20_million_people.html?cid=30643902