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Knowledge about the ideal host ratio per female parasitoid reared in glass tubes is important for obtaining descendants with better biological quality. The study aimed to evaluate the reproduction of Ooencyrtus submetallicus (Hymenoptera: Encyrtidae) females in egg densities of Euschistus heros (Hemiptera: Pentatomidae) to find the most adequate relationship between parasitoids and hosts aiming at the parasitoid multiplication. The experiment was conducted with E. heros eggs at densities (parasitoid:host) of 1:3, 1:6, 1:9, 1:12, 1:15, or 1:18 with 24 hours of parasitism by O. submetallicus. The parasitoid females and the egg carton were placed in glass tubes and kept in a climate-controlled chamber. The percentage of parasitism was affected by the nonparasitised eggs. The emergence of adult parasitoids, number of parasitised eggs, number of individual parasitoids emerging per egg, the length of the parasitoids’ posterior tibiae, and the parasitoids’ longevity, life cycle, and sex ratio were not affected by the different densities of nonparasitised eggs subjected to treatments. Ooencyrtus submetallicus parasitised and developed in E. heros eggs in all evaluated densities, with 1:6 presenting the best combination of parasitoid and host.

Selectivity is an important aspect of modern insecticides to be able to target pests whilst maintaining beneficial entomofauna in the crop. The present objective was to assess the selectivity of different insecticides for the pupal parasitoid of soybean caterpillars, i.e., Trichospilus diatraeae Cherian & Margabandhu, 1942 (Hymenoptera: Eulophidae). Acephate, azadirachtin, Bacillus thuringiensis (Bt), deltamethrin, lufenuron, teflubenzuron and thiamethoxam + lambda-cyhalothrin at the highest recommended concentrations for the soybean looper Chrysodeixis includens (Walker, [1858]) (Lepidoptera: Noctuidae), as well as water in the control, were used against the pupal parasitoid T. diatraeae. The insecticides and the control were sprayed on the soybean leaves, which were left to dry naturally and placed in cages with T. diatraeae females in each one. Survival data were submitted to analysis of variance (ANOVA) and the means were compared using Tukey’s HSD test (α = 0.05). Survival curves were plotted according to the Kaplan–Meier method, and the pairs of curves were compared using the log-rank test at 5% probability. The insecticides azadirachtin, Bt, lufenuron and teflubenzuron did not affect T. diatraeae survival, while deltamethrin and thiamethoxam + lambda-cyhalothrin presented low toxicity and acephate was highly toxic, causing 100% mortality in the parasitoid. Azadirachtin, Bt, lufenuron and teflubenzuron are selective for T. diatraeae and could be used in IPM programs.

Iridopsis panopla Prout (Lepidoptera: Geometridae) is an important lepidopteran defoliator of eucalyptus. I. panopla eggs were collected naturally in a commercial plantation of Eucalyptus urograndis W. Hill (Myrtaceae) in Três Lagoas, Mato Grosso do Sul, Brazil. After nine days, the natural emergence of Trichogramma pretiosum Riley (Hymenoptera: Trichogrammatidae) occurred from I. panopla eggs. Parasitism was evaluated under laboratory and field conditions, this being the first record for eucalyptus in Brazil. Based on the biological characteristics evaluated in the laboratory, I. panopla eggs are suitable for T. pretiosum reproduction. The obtained percentage parasitism, particularly when 72,000 adult females of T. pretiosum per hectare were employed, provide valuable insights regarding the potential of T. pretiosum as an effective biological control agent against I. panopla in eucalyptus plantations. Iridopsis panopla Prout (Lepidoptera: Geometridae) é um importante desfolhador de eucalipto. Ovos de I. panopla foram coletados naturalmente em uma plantação comercial de Eucalyptus urograndis, em Três Lagoas, Mato Grosso do Sul, Brasil. Após nove dias, ocorreu a emergência natural de Trichogramma pretiosum Riley (Hymenoptera: Trichogrammatidae) nos ovos de I. panopla. O parasitismo foi avaliado em condições de laboratório e campo, sendo este o primeiro registro para eucalipto no Brasil. Com base nas características biológicas avaliadas em laboratório, os ovos de I. panopla são adequados para a reprodução de T. pretiosum. As taxas de parasitismo obtidas, especialmente quando foram empregadas 72.000 fêmeas adultas de T. pretiosum por hectare, fornecem informações valiosas sobre o potencial de T. pretiosum como um agente de controle biológico eficaz contra I. panopla em plantações de eucalipto.

This study assessed the biological characteristics of Cotesia flavipes (Cameron) (Hymenoptera: Braconidae) with different densities of female parasitoids with Diatraea saccharalis (Fabricius) (Lepidoptera: Crambidae) caterpillars. Third instar caterpillars of D. saccharalis were exposed to C. flavipes females at parasitoid to host ratios of 1:1, 3:1, 6:1, 9:1, and 12:1, with 5 replications. The parasitism of C. flavipes was 90% at 3:1 ratio, and the emergence was 100% for all densities. The life cycle of C. flavipes ranged from 18.17 ± 0.26 to 18.93 ± 0.50 d with the densities of 12:1 and 1:1 parasitoid to host. The higher progeny of C. flavipes (87.38 ± 2.07 and 67.18 ± 2.57 individuals per D. saccharalis caterpillar) were obtained at the densities of 3:1 and 6:1, respectively. The sex ratio of parasitoid per D. saccharalis caterpillar ranged from 0.12 ± 0.05 to 0.66 ± 0.02 between the parasitoid to host densities of 12:1 and 3:1, respectively. The density of 3:1 C. flavipes females per D. saccharalis caterpillar was found to be optimal for propagation of the parasitoid.

Lepidoptera caterpillars are important pests around the world that decrease crop production, including that of soybeans. The use of insecticides and bioinsecticides is the main control strategy for these pests. Biological control with parasitoids, in combination with insecticides, is widely used as an alternative. However, the use of insecticides with parasitoids depends on tests to assess the survival/mortality of these natural enemies for each insecticide. Trichospilus diatraeae Cherian & Margabandhu, 1942 (Hymenoptera: Eulophidae) is a polyphagous pupal parasitoid that mainly comprises defoliating lepidopterans. This study evaluated the mortality of T. diatraeae from seven insecticides (acephate, azadirachtin, Bacillus thuringiensis (Bt), deltamethrin, lufenuron, teflubenzuron and thiamethoxam + lambda-cyhalothrin). The insecticides were sprayed on soybean leaves, which were left to dry and placed in cages with 10 T. diatraeae females. The insecticides azadirachtin, Bt, lufenuron and teflubenzuron did not affect T. diatraeae survival; deltamethrin and thiamethoxam + lambda-cyhalothrin presented low toxicity; and acephate was highly toxic, causing 100% mortality in this parasitoid. Azadirachtin, Bt, lufenuron and teflubenzuron are selective for T. diatraeae. Selectivity is an important aspect of modern insecticides to be able to target pests whilst maintaining beneficial entomofauna in the crop. The present objective was to assess the selectivity of different insecticides for the pupal parasitoid of soybean caterpillars, i.e., Trichospilus diatraeae Cherian & Margabandhu, 1942 (Hymenoptera: Eulophidae). Acephate, azadirachtin, Bacillus thuringiensis (Bt), deltamethrin, lufenuron, teflubenzuron and thiamethoxam + lambda-cyhalothrin at the highest recommended concentrations for the soybean looper Chrysodeixis includens (Walker, [1858]) (Lepidoptera: Noctuidae), as well as water in the control, were used against the pupal parasitoid T. diatraeae. The insecticides and the control were sprayed on the soybean leaves, which were left to dry naturally and placed in cages with T. diatraeae females in each one. Survival data were submitted to analysis of variance (ANOVA) and the means were compared using Tukey’s HSD test (α = 0.05). Survival curves were plotted according to the Kaplan–Meier method, and the pairs of curves were compared using the log-rank test at 5% probability. The insecticides azadirachtin, Bt, lufenuron and teflubenzuron did not affect T. diatraeae survival, while deltamethrin and thiamethoxam + lambda-cyhalothrin presented low toxicity and acephate was highly toxic, causing 100% mortality in the parasitoid. Azadirachtin, Bt, lufenuron and teflubenzuron are selective for T. diatraeae and could be used in IPM programs.

This study assessed the biological characteristcs of Cotesia favipes (Cameron) (Hymenoptera: Braconidae) with different densites of female parasitoids with Diatraea saccharalis (Fabricius) (Lepidoptera: Crambidae) caterpillars. Third instar caterpillars of D. saccharalis were exposed to C. favipes females at parasitoid to host ratos of 1:1, 3:1, 6:1, 9:1, and 12:1, with 5 replicatons. The parasitsm of C. favipes was 90% at 3:1 rato, and the emergence was 100% for all densites. The life cycle of C. favipes ranged from 18.17 [+ or -] 0.26 to 18.93 [+ or -] 0.50 d with the densites of 12:1 and 1:1 parasitoid to host. The higher progeny of C. favipes (87.38 [+ or -] 2.07 and 67.18 [+ or -] 2.57 individuals per D. saccharalis caterpillar) were obtained at the densites of 3:1 and 6:1, respectively. The sex rato of parasitoid per D. saccharalis caterpillar ranged from 0.12 [+ or -] 0.05 to 0.66 [+ or -] 0.02 between the parasitoid to host densites of 12:1 and 3:1, respectively. The density of 3:1 C. favipes females per D. saccharalis caterpillar was found to be optmal for propagation of the parasitoid.

This study assessed the biological characteristcs of Cotesia favipes (Cameron) (Hymenoptera: Braconidae) with different densites of female parasitoids with Diatraea saccharalis (Fabricius) (Lepidoptera: Crambidae) caterpillars. Third instar caterpillars of D. saccharalis were exposed to C. favipes females at parasitoid to host ratos of 1:1, 3:1, 6:1, 9:1, and 12:1, with 5 replicatons. The parasitsm of C. favipes was 90% at 3:1 rato, and the emergence was 100% for all densites. The life cycle of C. favipes ranged from 18.17 [+ or -] 0.26 to 18.93 [+ or -] 0.50 d with the densites of 12:1 and 1:1 parasitoid to host. The higher progeny of C. favipes (87.38 [+ or -] 2.07 and 67.18 [+ or -] 2.57 individuals per D. saccharalis caterpillar) were obtained at the densites of 3:1 and 6:1, respectively. The sex rato of parasitoid per D. saccharalis caterpillar ranged from 0.12 [+ or -] 0.05 to 0.66 [+ or -] 0.02 between the parasitoid to host densites of 12:1 and 3:1, respectively. The density of 3:1 C. favipes females per D. saccharalis caterpillar was found to be optmal for propagation of the parasitoid. Key Words: biological control; larval parasitoid; sugarcane borer Este estudo avaliou as caracteristcas biologicas de Cotesia favipes (Cameron) (Hymenoptera: Braconidae) com differentes densidades de femeas de C. favipes, com lagartas de Diatraea saccharalis (Fabricius) (Lepidoptera: Crambidae). Lagartas do terceiro instar de D. saccharalis foram expostas as femeas de C. favipes na seguinte proporcao (parasitoide para hospedeiro): 1:1, 3:1, 6:1, 9:1, e 12:1, com 5 repetcoes. O parasitsmo de C. favipes foi de 90% na densidade de 3:1, e a emergencia foi de 100% para todas as densidades. O ciclo de vida de C. favipes variou de 18,17 [+ or -] 0,26 a 18,93 [+ or -] 0,50 dias, com as densidades de 12:1 e 1:1 parasitoide:hospedeiro. A maior progenie de C. favipes (87,38 [+ or -] 2,07 e 67,18 [+ or -] 2,57 individuos por lagarta D. saccharalis) foi obtda nas densidades de 3:1 e 6:1, respectvamente. A razao sexual deste parasitoide por lagarta de D. saccharalis variou de 0,12 [+ or -] 0,05 a 0,66 [+ or -] 0,02 entre as densidades parasitoide para hospedeiro. A densidade de femeas de C. favipes 3:1 por lagarta de D. saccharalis foi considerada ideal para a multplicacao propagacao desse parasitoide. Palabras Clave: controle biologico; parasitoide de larvas; broca da cana-de-acucar