TOXICOLOGICAL INTERACTIONS BETWEEN SPINOSAD AND ESSENTIAL OILS ON THE MEDITERRANEAN FRUIT FLY, CERATITIS CAPITATA (DIPTERA: TEPHRITIDAE)

CORTEZ VEGA, ANA ROMINA; BARUD, FLAVIA JOFRÉ; ANDINO, NATALIA; GOMEZ, MARÍA PÍA; LÓPEZ ,M. LIZA

Congreso; 6th Congress of the Latin American Association of Chemical Ecology (ALAEQ; 2021

Asociacion Latinoamericana de Ecologia Química

Ceratitscapitata is considered one of the most harmful pest speciesamong fruit flies of economic importance. Historically it was controlled withinsecticides but these products have negative impacts, such as pest resistancedevelopment. The present study aims to evaluate the toxicological interactionsbetween toxic essential oils (EOs) (Baccharis spartioides, Eucalyptuscinerea and Schinus areira) and the bioinsecticide Spinosad onadults of C. capitata, inorder to decrease the concentration of active ingredient bioinsecticide andprevent resistance development. We dispensed2 µl of each test solution on each fly (EOs doses 10, 25, 50 and 100 µg/insect;Spinosad doses 25, 50, 100, 200 and 400 ng/insect). According to these resultswe then prepared 4 formulations of mixtures (EO and Spinosad) considering theLoewe additivity model (⅛, ⅙, ¼ and ½). Mortality was recorded after 24, 48 and 72h of treatment. We calculated lethal dose for 50% of mortality (LD50)and isobolograms were used to determinate toxicological interactions betweenmixtures of EOs and Spinosad. The LD50 at 48 h were: for B.spartioides: 62,48 and 34,76 µg/insect; for E. cinerea: 107,25 and53,02 µg/insect; for S. areira: 51,25 and 38,11 µg/insect; and for Spinosad:826,68 and 266,57 ng/insect; for females and males, respectively. Synergisticactivity was found for B. spartioides-Spinosad on females and for S.areira-Spinosad on both sexes; whereas antagonistic activity was found for B.spartioides-Spinosad and E. cinerea-Spinosad on males. Finally, additiveactivity was found for E. cinerea-Spinosad on females. We highlightedthat the ½ S. areira-Spinosad ratio registered higher mortality than thehighest dose of the insecticide (400 ng) administered alone. This mixture couldbe the basis for a new tool or for the integrated pest management of C. capitata.