ABSTRACT
This study was aimed to evaluate the toxicity of some fungicides applied on cucumber crop (Cucumis sativus L.) in function in the manner of exposure, by contact or ingestion of contaminated preys, for first-instar Chrysoperla externa (Hagen) larvae fed with Aphis gossypii Glover (Hemiptera: Aphididae), and the effects on the subsequent stages of the predator. The experiments were conducted under controlled conditions at 25 ± 2oC; RH: 70 ± 10% and 12h of photophase. The experimental design was completely randomized with 4 treatments and 6 replicates, each plot made up of 4 larvae. The compounds utilized and their respective dosages of application in g a.i.L-1 were sulfur (Kumulus 800PM – 1.6), mancozeb (Manzate 800PM – 1.6) and copper oxichloride (Recop 840PM – 1.49). The control consisted of distilled water. First-instar larvae received the chemicals via spraying and were then individualized into glass tubes, and fed A. gossypii nymphs. In the bioassay, via ingestion, the A. gossypii nymphs treated via spraying with the compounds were given as food to first-stage larvae of C. externa. The total effect of the fungicides from C. externa was established according to the toxicity classes of the IOBC scale, where copper oxichloride proved harmless (class 1) via contact or ingestion. Sulfur and mancozeb by ingestion were harmless, and slightly harmful (class 2) when applied via contact.
KEY WORDS
Cucurbitaceae; pesticide; aphid; green lacewing
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