Bioatividade de pó de mastruz (Chenopodium ambrosioides L.) sobre Alphitobius diaperinus (Panzer, 1977)(coleoptera: tenebrionidae).

Abstract

The great development and evolution in the Brazilian poultry production in the last times has made possible the production index increase, playing a very significant role both nationally and internationally in the agricultural and livestock industry. On the other hand, problems related to the insect pests, as is the case of Alphitobius diaperinus, commonly known as lesser mealworm, has been consider a limiting factors to poultry production. The present research aimed to evaluate the bioinseticidal effects of Chenopodium ambrosioides L. powder in different doses in the control of A. diaperinus. To evaluate these effects, efficiency and repellency bioassays were carried out. The efficiency of C.ambrosioides powder was studied at doses of 0,0; 0,5; 0,75; 1,0 g/cm2 and at four periods (7, 14, 21 and 28 days) at the Phytosanitary Laboratory of CDSA/UFCG. Treatments consisted of plastic containers of 6cm length and 5cm height (30 cm2), simulating the poultry litter conditions, in which C. ambrosioides powder was used in the inferior layer of the recipient and rice husk (2 cm height) in the superior layer. Above the C.ambrosioides and rice husk layers poultry feed were added. Afterwards, 30 insects were placed in each experimental unit. In the first bioassay, the efficiency of C.ambrosioides powder was calculated by the method of Abbott (1925). Data were submitted to analysis of Variance by the F test (P≤0,05) and the means were compared by the Tukey test (P≤0,05). The second bioassay evaluated the potential of C. ambrosioides powder in repelling adults of A.diaperinus, using wood recipients with three compartments (with or whithout C. ambrosioides) of 6cm length and 6cm height (36 cm2), with 10 replicates. In the center of the device, 30 adult insects were released and after 24 hours, the number of insects, attracted or repelled in each recipient, was recorded. The effect of plant powders on A.diaperinuswas evaluated using the Repellency Index (IR) and polynomial regression. According to the results, we concluded that the C.ambrosioides powder at 1,0 g/cm2 was the most efficient dose, with efficiency values of 69,29% at 7 days and 98,46% at 28 days. The Repellency Index was lesser than one, indicating that all tested doses were repellent to A.diaperinus.