Óleo essencial de Eugenia uniflora L. (Myrtaceae) sobre Alphitobius diaperinus (Panzer) 1797 (Coleoptera: Tenebrionidae)

Abstract

Alphitobius. diaperinus is one of the main pests of poultry production, causing direct and indirect damage. Its control is done predominantly with synthetic chemical insecticides, which results in several problems, for both the birds and the producer. In this sense, it’s important to seek new insect control methods. One possibility is the use of plant extracts, because these may have insecticidal, repellent or deterrent effect, coming from the secondary metabolites. Thus, the aim of this work was to evaluate the insecticide potential of E. uniflora oil on adults and larvae of A. diaperinus. For this purpose, essential oil application experiments in different concentrations were done (0,25%; 0,50%; 0,75; 1,0%; 1,25%; 1,50%), by contact and ingestion. For the ingestion experiment, the oil concentrations (treatments) were mixed in a volume of 10 ml in commercial poultry feed, previously sterilized. In the experiment with adults it was used 40g of poultry feed and 20g for larvae. After the mixture, the total volume of feed was divided into eight equal pieces (replicates) with 12 insects in each. For adults, the repetitions were placed in Petri dishes and for larvae in acrylic plates with individual pit and placed in climate-controlled chamber (27 ± 2 ° C, 14 hours of photoperiod). The evaluation was done daily for 10 days, quantifying the number of dead. For the experiment by contact, in plastic containers with a volume of 50 ml , the insects were immersed in 1 ml of oil concentrations and stirred for 5 seconds, and then placed in the plates (replicates) with poultry feed. The experimental design, the bioassay assembly and the evaluation were the same as described for the experiment by ingestion. It was checked that the E. uniflora essential oil didn't show insecticidal effect on larvae and adults of A. diaperinus in the bioassay by ingestion and for adults in the experiment by contact. For larvae in the bioassay by contact, all the oil concentrations (0.25%, 0.50%, 0.75%, 1.00%, 1.25%; 1:50%) showed insecticide effect, with respective percentages of mortality 58%; 56%; 57%; 63%; 54%; 52. It was concluded that the essential oil E. uniflora obtained satisfactory results for the control of A.diaperinus larvae. However, future studies in semi-field and field conditions are necessary to assert its effectiveness.