A slight increase in the levels of a certain nutrient can cause a signifi cant increase in crop yield or can cause phytotoxicity symptoms. Thus, the aim of this study was to evaluate the effect of foliar application of copper (Cu

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Tetrastichus howardi (Olliff, 1893) (Hymenoptera: Eulophidae) é um parasitoide larval e pupal de insetos, principalmente da ordem Lepidoptera, e é considerado um promissor agente de controle biológico. O desenvolvimento de técnicas de criação é de fundamental importância para a implantação e o aprimoramento dos programas de controle biológico utilizando inimigos naturais. O objetivo deste trabalho foi avaliar a influência da idade de pupas de Diatraea saccharalis (Fabricius, 1794) (Lepidoptera: Crambidae) sobre o parasitismo e o desenvolvimento de T. howardi. O experimento foi conduzido em delineamento inteiramente casualizado, com cinco tratamentos e cinco repetições, sendo cada uma representada por um grupo de dez pupas de D. saccharalis individualizadas, totalizando 50 pupas por tratamento. Pupas de D. saccharalis com 24, 48, 72, 96 e 120 h de idade foram expostas ao parasitismo por três fêmeas de T. howardi em tubos de vidro (10 × 1,5 cm). As fêmeas de T. howardi foram retiradas após 24 h e as pupas mantidas a 25±2 °C, 70±10% de umidade relativa (UR) e fotofase de 14 h. O número de pupas parasitadas e a emergência e a progênie de T. howardi em pupas de D. saccharalis não foram influenciados pela idade do hospedeiro, mas o ciclo de vida de T. howardi foi menor em pupas com 24 h de idade e maior em pupas de 120 h. De maneira geral, pupas de D. saccharalis com idades entre 24 e 120 h são adequadas para a multiplicação do parasitoide T. howardi em laboratório.

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BioOne Complete (complete.BioOne.org) is a full-text database of 200 subscribed and open-access titles in the biological, ecological, and environmental sciences published by nonprofit societies, associations, museums, institutions, and presses.

The number of Tetrastischus howardi (Olliff) females to be released and their dispersion should be known, that way, used D. saccharalis pupae as sentinel host to measure parasitism as function of the release density of the parasitoid and its location in the field. Two sets of trials were run aiming first to define the number of parasitoids to be released and the dispersal of the parasitoid using plots in sugarcane commercial fields, respectively. Pieces of sugarcane stalk holding sentinel pupae were taken to the field and exposed to parasitism in both trials. The parasitoid was released at the rate of 20, 40, 80, and 160 females per sentinel pupa, except for the control plot without releasing. The parasitism rate was calculated based on the recovered pupae after 96 h of exposure time from releasing the parasitoids. The models estimated the best parasitism rate by releasing 102 parasitoids per pupa. In the second trial, sentinel pupae were arranged in five subsequent circles corresponding 4, 8, 12, 16, and 20 m around the central parasitoid releasing point at rate of 4, 8, 12, 16, and 18 pupae per circle. The mean estimated dispersal distance was 7.64 m, with a covering area of 80.07 m 2 . Based on these findings, release of T. howardi is recommended in 125 points per hectare of sugarcane at rate of 102 females per pupa of the pest aiming to achieve homogeneous distribution and parasitism.

Understanding mortality patterns and interactions between entomopathogenic fungi and parasitoids is important to improve insect biological control programs. The aim of this study was to evaluate the effect of Metarhizium anisopliae (Metschnikoff, 1879) Sorokin, 1833 and Beauveria bassiana (Balsamo) Vuillemin, 1912 (Hypocreales: Clavicipitaceae) on adults of Cotesia flavipes (Cameron, 1891) (Hymenoptera: Braconidae) with biological insecticides Biometha WP Plus ® (M. anisopliae), Biovéria G ® (B. bassiana), Boverril WP ® (B. bassiana), Metarril WP ® (M. anisopliae), and Metiê WP ® (M. anisopliae) at concentrations of 1 × 10 9 conidia (con).mL-1 , 5 × 10 9 con.ml-1 , and 10 × 10 9 con.ml-1. In the experimental, 10 females of C. flavipes were packed in disposable cups capped with a contact surface (filter paper, 9 cm 2) treated with commercial product. The experimental design was completely randomized, with 16 treatments and five replicates of 10 females each. Mortality was assessed at 24, 48, 72, 96, and 120 hours after exposition (HAE) of the products. In general, B. bassiana and M. anisopliae in the concentrations of 1 × 10 9 con.ml-1 , 5 × 10 9 con.ml-1 , and 10 × 10 9 con.ml-1 can't affect C. flavipes females because the peak of mortality in treatments with bioinsecticides was similar to the control and this demonstrated the selectivity of fungi B. bassiana and M. anisopliae on C. flavipes females.

BioOne Complete (complete.BioOne.org) is a full-text database of 200 subscribed and open-access titles in the biological, ecological, and environmental sciences published by nonprofit societies, associations, museums, institutions, and presses.