Abstract The objective of this study was to assess the efficiency of essential oils of cloves (Syzygium aromaticum) and thyme (Thymus vulgaris) on the control of Acanthoscelides obtectus in laboratory conditions. The extraction of the oils was executed by the hydro-distillation method in a Clevenger device, for 4 hours and the design used was completely randomized, with five replications, in a 10x8 factorial arrangement (dozes and exposition time) with ten concentrations (20; 10; 5; 2.5; 1.75; 0.75; 0.5; 0.25 and 0.0% and Tween® 5.0%). Each replication was comprised by 10 unsexed insects of A. obtectus. The variables evaluated are as follows: control efficiency and CL50 through the Proc Probit analysis. The evaluations were carried out in 1, 2, 3, 12, 24, 48, 72, and 96 hours after the treatment. The results demonstrate that the essential oils of cloves and thyme caused 100% of mortality after 48 and 72 hours, respectively, in the 20% concentration. The Cl50 was estimated at 30.46 µL mL-1 for the oil of cloves and 24.93 µL mL-1 for the oil of thyme. The use of essential oils of cloves and thyme represent a viable alternative for use in storehouses for the integrated management of A. obtectus.

Abstract Anastrepha fraterculus (Wiedemann, 1830) (Diptera: Tephritidae) is a major fruit pest, which is basicaly controlled using insecticides, which represents a risk to beneficial arthropods, human health and food contamination. The sterile insect technique (SIT) is a potential alternative tool for the management of this pest, however, only conflicting data is found regarding the optimal dose to achieve sterility. Thus, this study evaluated the effect of gamma radiation doses (0, 40, 50, 60 and 70 Gy) on male and female reproductive sterility, gonads morphometry, emergence, flight ability, and longevity under nutritional stress of A. fraterculus. Full female sterility was achieved at 50 Gy, while full male sterility was achieved at 70 Gy. Both ovarian and testicular sizes were affected by irradiation, while no influence was observed on the quality parameters evaluated. Our results suggest that 70 Gy applied 48 h before adult emergence can be used to sterilize A. fraterculus in a SIT programme.

RESUMO O gorgulho-do-milho (Sitophilus zeamais) pode causar grande prejuízo na cultura e nos grãos de milho armazenados. O controle deste inseto é efetuado através do uso de inseticidas químicos passíveis de ocasionar sérios problemas à saúde humana; uma alternativa de controle é a utilização de pós inertes. O presente trabalho objetivou avaliar a eficiência de pós inertes no controle de S. zeamais em condições de laboratório. O experimento foi conduzido durante o ano de 2014; os tratamentos, constituídos por pó de basalto em três diferentes granulometrias (A, B e C) e terra de diatomáceas, cada um nas doses de 2 e 4 kg t-1 e ainda testemunha (sem aplicação), foram realizados em delineamento experimental inteiramente casualizado. Cada tratamento foi constituído de quatro repetições e a unidade amostral composta por 20 g de grãos de milho infestados com 10 adultos de S. zeamais mantidos em câmara climatizada com temperatura de 25 ºC, UR 70% e foto-fase de 12 h, pela equação de Abbott foi calculada a eficiência dos pós; a mortalidade foi mais rápida com a terra de diatomácea chegando a 100% cinco dias após a exposição; a porcentagem de controle com os pós de basalto, 29 dias após os tratamentos, foi superior a 80%.

ABSTRACT Corn weevil (Sitophilus zeamais) may cause great losses in the crop and in stored corn grains. This insect is controlled with the use of chemical insecticides, which may cause serious damage to human health. One alternative of control is the use of inert dusts. The objective of this study was to evaluate the efficiency of inert dusts in the control of S. zeamais under laboratory conditions. The experiment was conducted in 2014, in a completely randomized design, and the treatments consisted of basalt dust with three different granulometries (A, B and C) and diatomaceous earth, each of which at the doses of 2 and 4 kg t-1 and a control (no application). Each treatment had four replicates, and the sample unit consisted of 20 g of corn grains infected with 10 adults of S. zeamais kept in temperature-controlled chamber at 25 °C, 70% RH and photophase of 12 h. The dust efficiency was calculated using the equation of Abbott. The mortality rate was higher with the use of diatomaceous earth, reaching 100% after 5 days of exposure and the percentage of control for basalt dusts, 29 days after treatment, was above 80%.

RESUMO O caruncho-do-feijão e o gorgulho do milho podem causar grandes prejuízos aos grãos armazenados. Entre as alternativas de controle está a utilização de óleos essenciais de plantas com propriedades inseticidas; objetivou-se, assim, avaliar a eficiência do óleo essencial de cravo-da-índia no controle de S. zeamais e A. obtectus em condições de laboratório. O óleo essencial foi extraído por processo clássico de hidrodestilação e seus constituintes químicos foram identificados por cromatografia gasosa. A eficiência deste óleo foi testada nas doses 35; 17,9; 8,9; 3,6; 1,8; 0,4 e 0,2 μL g-1 (oriundas de um trabalho piloto) no controle dos insetos e determinada a CL50. Os resultados mostraram que o eugenol foi o composto majoritário. O óleo essencial causou 100% de mortalidade para as duas espécies 48 h após o tratamento com as concentrações de 17,9 e 35 μL g-1. A CL50 para A. obtectus foi 9,45 μL g-1 contra 10,15 μL g-1 do S. zeamais. A utilização do óleo essencial de cravo-da-índia representa uma alternativa promissora a ser usada em condições de armazenagem para o manejo integrado de pragas de grãos armazenados.

ABSTRACT Bean weevil and maize weevil can cause considerable damage to stored grains. These insects are mainly controlled with synthetic chemical insecticides, which may bring serious problems to human and environmental health. Therefore, this study aimed to evaluate the efficiency of the essential oil of clove [Syzygium aromaticum (L.) Merrill & Perry (Myrtaceae) (origin: Bahia, season Sep.2014-Feb.2015)] in the control of S. zeamais and A. obtectus under laboratory conditions. The essential oil was extracted through the classic hydrodistillation process and its chemical components were identified via gas chromatography. Oil efficiency was tested at the doses of 35, 17.9, 8.9, 3.6, 1.8, 0.4 and 0.2 μL g-1 (derived from a pilot study) for insect control and the LC50 was determined. The results showed that eugenol was the major compound. The essential oil caused mortality of 100% for both species 48 h after treatment with the concentrations of 17.9 and 35 μL g-1. The LC50 for A. obtectus was 9.45 μL g-1, against 10.15 μL g-1 for S. zeamais. The use of clove essential oil represents a promising alternative to be used under storage conditions for the integrated management of stored grains pests.