Olive Flies in Spain Are Immune to Common Pesticide, Study Finds

Roughly 80 percent of olive fruit fly populations on the mainland have genes that confer resistance to one of the most popular pesticides.

By Daniel Dawson
Sep. 22, 2020 10:38 UTC

Olive fruit fly pop­u­la­tions in Spain have devel­oped genetic resis­tance to a com­mon type of pes­ti­cide used to con­trol and elim­i­nate them, accord­ing to newly pub­lished research from the Complutense University of Madrid.

The study, which was pub­lished in the aca­d­e­mic jour­nal Insects, found that more than 80 per­cent of olive fruit fly pop­u­la­tions on the Spanish main­land have genes that con­fer a high level of resis­tance to the com­monly-used organophos­phate pes­ti­cides.

See Also:Study on Fruit Fly Control Wins Research Award

The lev­els of resis­tance to organophos­phate pes­ti­cides were found to be con­sis­tent in fruit fly pop­u­la­tions regard­less of the type of olive grove (i.e. organic, super-high-den­sity, tra­di­tional) in which they were found.

Normally, organophos­phate pes­ti­cides work by inhibit­ing the acetyl­cholinesterase pro­tein, which breaks down the chem­i­cal acetyl­choline, a neu­ro­trans­mit­ter respon­si­ble for mus­cle con­trac­tion.

Organophosphate insec­ti­cides irre­versibly block acetyl­cholinesterase, there­fore, acetyl­choline is not degraded, which causes pro­longed paral­y­sis of the insect and with it, its death,” Esther Lantero, a researcher at the university’s depart­ment of genet­ics, phys­i­ol­ogy and micro­bi­ol­ogy said.

However, the researchers said that the overuse of these pes­ti­cides on olive trees across the coun­try have caused three dif­fer­ent types of muta­tions to the ace gene. Each of these muta­tions has an adverse effect on the way in which the pes­ti­cides inter­acted with the acetyl­cholinesterase pro­tein and decreased their effi­cacy.

It is essen­tial to find effec­tive alter­na­tives that sig­nif­i­cantly reduce the den­sity of the olive fly pop­u­la­tions,” Lantero said. For this rea­son, efforts should focus on the search for bio­log­i­cal, cul­tural, biotech­no­log­i­cal or phys­i­cal meth­ods that reduce the use of chem­i­cals, con­cen­trat­ing the approach based on bio­log­i­cal con­trol.”

Along with test­ing olive fruit fly pop­u­la­tions from 12 dif­fer­ent Spanish regions, the researchers also tested pop­u­la­tions from 12 other regions spread across five coun­tries in the Mediterranean.

They found high degrees of resis­tance to organophos­phate pes­ti­cides from selected pop­u­la­tions in Greece and Italy (at least 95 per­cent), while pop­u­la­tions from Israel and Portugal had sig­nif­i­cantly lower lev­els of resis­tance (closer to 50 per­cent).

Meanwhile, pop­u­la­tions from Tunisia and Spain’s Balearic Islands had nearly neg­li­gi­ble lev­els of resis­tance.


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