Lethality of pesticides on immature and adult stages of Ceratitis capitata (Diptera: Tephritidae)

Abstract

The species Ceratitis capitata (Weidemann, 1824), known as Mediterranean fruit fly, is an important pest for fruit trees worldwide. The control of this pest is carried out mainly by the chemical method, using organophosphorus, pyrethroid, and spinosyn pesticides. The lethality of doses of malathion, deltamethrin, and spinetoram on immature and adult stages of C. capitata was evaluated under laboratory conditions. The egg, larval, pupal, and adult stages were exposed to doses of pesticides through contact and ingestion. The doses were obtained by decreasing the recommended doses (malathion: 200 mL L⁻¹, deltamethrin: 50 mL L⁻¹, and spinetoram: 120 g ha⁻¹) with intervals of 20%, this being the minimum dose used. The variables evaluated were: viability of eggs and pupae and mortality of larvae and adults. Application of spinetoram and malathion through contact caused high mortality of adults, with LD₉₀ at the sub-doses of 43.74% (52.48 g c.p. ha⁻¹) and 68.81% (137.62 mL c.p. 100 L⁻¹), respectively. The mortality of adults by ingestion of deltamethrin and malathion allowed us to estimate only the LD₅₀. Only the pesticide deltamethrin presented LD₅₀ for the egg stage. The larval and pupal stages the effect of the pesticides on larvae treated through contact resulted in 52% mortality with spinetoram and 62% with malathion. The mortality of larvae and pupae treated through ingestion was below 20% for the three pesticides. Sub-doses of spinetoram (43.74%; 52.48 g c.p. ha⁻¹) and malathion (68.81%; 137.62 mL c.p. 100 L⁻¹) can be used since they present a 90% efficiency on C. capitata adult when applied by contact under laboratory conditions.