Rogério Hidalgo Barbosa

Foliar copper uptake by maize plants: effects on growth and yield

A slight increase in the levels of a certain nutrient can cause a significant 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) on the growth and yield of DG-501 maize. The experiment was carried out between December 2009 and April 2010 in conventional tillage. When plants were with six to eight leaves, Cu (0, 100, 200, 300, 400, 500 and 600g ha-1) was applied to the leaves. Treatments were arranged in randomized complete block with five replications. When 50% of the plants were in flowering, it was evaluated the plant height, culm diameter, height of the first ear insertion, leaf area, and chlorophyll content. At harvest, it was evaluated diameter and length of the ear, yield and thousand grain weight. There was a linear reduction in the plant height and in the height of the first ear insertion with increasing Cu doses. On the other hand, chlorophyll content, leaf area, diameter and length of ear, thousand grain weight and yield increased at doses up to 100g ha-1 Cu, however, decreased at higher doses. Therefore, foliar Cu application at doses higher than 100g ha-1 has toxic effect in maize plants with losses in growth and yield.

Combinations of Metarhizium anisopliae with Chemical Insecticides and their Effectiveness in Mahanarva fimbriolata (Hemiptera: Cercopidae) Control on Sugarcane

Abstract Some insecticides can be used jointly with entomopathogenic fungi, and therefore the combination of chemical and biological control measures can be a safe and effective method to control insect pests. The aim of this study was to evaluate the costs and efficacy of combinations of Metarhizium anisopliae (Metschnikoff) Sorokin (Hypocreales: Clavicipitaceae) with thiamethoxam and imidacloprid on spittlebug (Mahanarua fimbriolata (Stål); Hemiptera: Cercopidae) control on sugarcane. The experiment was conducted as a randomized block design (RBD) with 10 treatments and 4 replications. The treatments included a control (untreated), thiamethoxam (250 g ha-1), imidacloprid (700 g ha-1), M. anisopliae (M. a.) (3 × 1012 conidia ha-1), A1 (3 × 1012 M. a. conidia ha-1 + 65 g ha-1 of thiamethoxam), A2 (3 × 1012 M. a. conidia ha-1 + 125 g ha-1 of thiamethoxam), A3 (3 × 1012 M. a. conidia ha-1 + 187.5 g ha-1 of thiamethoxam), A4 (3 × 1012 M. a. conidia ha-1 + 175 g ha-1 of imidacloprid), A5 (3 × 1012 M. a. conidia ha-1 + 350 g ha-1of imidacloprid), and A6 (3 × 1012 M. a. conidia ha-1 + 525g ha-1 of imidacloprid). The reductions in the numbers of M. fimbriolata nymphs per treatment compared to the control were similar at 15 DAT (days after treatment) in all treatments except combination A5 (M. anisopliae and thiamethoxam). At 30 DAT, the numbers of nymphs were significantly reduced in all treatments except A3, and their effectiveness ranged from 14.28% to 92.85%. At 45 DAT the numbers of M. fimbriolata nymphs per treatment were significantly reduced in the following treatments: imidacloprid alone at 700g ha-1, A1, A2, A3, A4 and A6; and the combinations A1 and A2 caused the lowest M. fimbriolata nymph infestations and effectiveness rates of 77.41 and 87.09 %, respectively. At 75 DAT the 2 best control efficacies occurred in treatments A1 (3 × 1012 M. a. conidia ha-1 of + 65g ha-1 of thiamethoxam) (82.1%) and A5 (78.6%) (3 × 1012 M. a. conidia ha-1 + 350 g ha-1of imidacloprid). At 90 DAT the number of nymphs in the control had increased 2.8 fold over the number at 75 DAT. Very good control efficacies at 90 DAT occurred in all treatments with the combination of the fungus with an insecticide. At 105 DAT the numbers of nymphs had surged in all treatments, and no treatment provided effective control. The treatments with the highest earnings per hectare were A1 (3 × 1012 M. a. conidia ha-1 + 65 g thiamethoxam) and M. anisopliae alone at the recommended dose of 3 × 10 12 M. a. conidia ha-1. Our findings demonstrate the effectiveness of using either thiamethoxam or imidacloprid in combination with M. anisopliae to control M. fimbriolata nymphs on sugarcane, but greater net earnings per hectare occurred with the lowest rate of the thiamethoxam combination than with any of the imidacloprid combinations.

Biological characteristics of Palmistichus elaeisis Delvare & LaSalle (Hymenoptera: Eulophidae) on refrigerated pupae of Anticarsia gemmatalis Hubner (Lepidoptera: Noctuidae)

Mass rearing of parasitoids is a fundamental step for biological control programs. The biological characteristics of Palmistichus elaeisis Delvare & LaSalle (Hymenoptera: Eulophidae) were evaluated in pupae of Anticarsia gemmatalis Hubner (Lepidoptera: Noctuidae) stored at low temperatures. Twenty four hours-old pupae of A. gemmatalis were stored at 12 ° C for 0, 1, 3, 6, 9, and 12 d and then exposed to parasitism by P. elaeisis females. The life span of P. elaeisis was affected and ranged from 19 to 24 d on the pupae of the host. Parasitism reached 100% of the host pupae after storage in all periods at 12° C, and adults emerged from 20.00 to 54.54% of them. The progeny of P. elaeisis ranged from 71 to 198 and had an inverse relationship with the increase in the storage period. Pupae of A. gemmatalis may be stored for up to 6 d at 12 ° C and subsequently used in rearing of P. elaeisis.

Metarhizium anisopliae and Beauveria bassiana (Hypocreales: Clavicipitaceae) are compatible with Cotesia flavipes (Hymenoptera: Braconidae)

Abstract The aim of this study was to evaluate the effects of commercially available bioinsecticides based on Metarhizium anisopliae (Metschnikoff) Sorokin and Beauveria bassiana (Balsamo) Vuillemin, i.e., Biometha WP Plus® (M. anisopliae), Biovéria G® (B bassiana), Boverril WP® (B. bassiana), Metarril WP® (M. anisopliae), and Metiê WP® (M. anisopliae) on the pupae and adults of Cotesia flavipes (Cameron) (Hymenoptera: Braconidae) at concentrations of 1 × 109, 5 × 109, and 10 × 109 conidia mL-1. This braconid is released to control the sugarcane borer, Diatraea saccharalis. In the completely randomized first experiment with each commercial product, 10 C. flavipes female adults were held individually in disposable cups, which contained a 9-cm2 sugarcane leaf that had been treated with the one of the entomopathogenic fungal products. The mortality of C. flavipes females was assessed at 24, 48, 72, 96, and 120 h after treatment. In the second experiment, the same treatments were applied to C. flavipes pupae, because the latter can be exposed when the fungal products are applied to sugarcane to control various pests. In the second experiment we assessed the emergence of adults from treated pupae, the capacity of these adults to parasitize Diatraea saccharalis caterpillars, numbers of progeny of these C. flavipes, longevity of C. flavipes males and females, total adults emerged, and the percent emergence and longevity of males and females of the F1 generation. The mortality levels of C. flavipes pupae and adults were not affected by the 2 Entomopathogenic fungi. Therefore the use of Beauveria bassiana and M. anisopliae to protect sugarcane is compatible with the use of C. flavipes to suppress D. saccharalis.

Associação de Metarhizium anisopliae (Hyp.: Clavicipitaceae) com thiamethoxam para o controle da cigarrinha-das-raízes em cana-de-açúcar

O objetivo do trabalho foi avaliar a compatibilidade entre diferentes cepas de Rhizobium tropici e o fungo Trichoderma harzianum no tratamento de sementes de feijao (Phaseolus vulgaris L.). O experimento foi realizado na area da fazenda – escola da FAR/ Anhanguera no municipio de Rondonopolis – MT. O delineamento adotado foi inteiramente casualizado (DIC) consistindo em 8 tratamentos e 3 repeticoes, sendo estes: T1 (testemunha); T2 ( Inoculante A BR 322); T3 (Inoculante B BR 520); T4 (Inoculante C BR 320); T5 (Inoculante A BR 322 + Trichoderma harzianum); T6(Inoculante B BR 520 + Trichoderma harzianum); T7 (Inoculante C BR 320 + Trichoderma harzianum); T8 (Trichoderma harzianum). A cepa A de Rhizobium tropice (BR 322) obteve melhor compatibilidade quando associada com o fungo Trichoderma harzianum.

Foraging Activity of Palmistichus elaeisis (Hymenoptera: Eulophidae) at Various Densities on Pupae of the Eucalyptus Defoliator Thyrinteina arnobia (Lepidoptera: Geometridae)

Abstract Parasitoids are the main component of biological control of Lepidoptera defoliators in forested areas, and the densities of host insects can affect the efficiency of these natural enemies. The aim of this work was to study the biology and parasitism of Palmistichus elaeisis Delvare & LaSalle (Hymenoptera: Eulophidae) at various densities of females on individual pupae of Thyrinteina arnobia Stoll (Lepidoptera: Geometridae), the major Lepidoptera pest in eucalyptus (Myrtaceae) plantations in Brazil. Thyrinteina arnobia pupae were exposed to P. elaeisis females at various parasitoidto-host ratios: (1:1, 3:1, 6:1, 9:1, 12:1, 15:1, 18:1, and 21:1), with 12 replications. The parasitism (81.8%) and emergence (100%) rates of P. elaeisis on T. arnobia pupae were highest with 15 ovipositing females per host. The life cycle (egg to adult) of P. elaeisis was shortest (19.8 ± 0.5 d) at a ratio of 21:1. The largest production of P. elaeisis per T. arnobia pupa was obtained at the ratios of 15:1 (298.4 ± 5.0) and 18:1 (287.4 ± 4.3). The female sex ratio of parasitoid offspring was highest (0.97 ± 0.01) with a parasitoid-to-host ratio of 12:1. The density of 15 P. elaeisis females per T. arnobia pupa was the most appropriate one for providing high parasitism (81.8%), emergence (100%), and progeny (298.4 ± 5.0) of this parasitoid.

Alteração no método de amostragem de Mahanarva fimbriolata (Stål, 1854) (Hem.: Cercopidae) e avaliação da eficiência de Metarhizium anisopliae (Metschnikoff, 1879) Sorokin, 1883 (Hyp.: Clavicipitaceae)

The present study suggests a change in the method of sampling the spittlebug in sugarcane crops in order to improve the control of this pest. Conventional monitoring of Mahanarva fimbriolata may underestimate the number of eggs in the area, causing pest resurgence. In this regard a study was carried out in Ponta Pora, MS, Brazil, in order to study possible changes in the methods used for sampling M. fimbriolata. The experiment consists of randomized blocks with 10 treatments and 4 replications. The treatments were: 1) control - untreated, 2) Thiamethoxam 250 WG at 250 g ha-1, 3) IBCB 425 at 5 x 109 con ha-1, 4) IBCB 425 at 10 x 109 con ha-1, 5) IBCB 425 at 15 x 109 con ha-1, 6) BIO 08 at 5 x 109 con ha-1, 7) BIO 08 at 10 x 109 con ha-1, 8) BIO 08 at 15 x 109 con ha-1, 9) IBCB 425 at 5 x 109 con ha-1 - granular application and 10) BIO 08 at 5 x 109 con ha-1 - granular application. Evaluations of effectiveness of treatments were obtained at 15, 45, 75 and 105 days after application (DAA). At 15 DAA treatments with the isolated application with grainy BIO 08 and IBCB 425 at dosage of 5 x 109 con ha-1 and 10 x 109 con ha-1 showed an efficiency of 73.33 and 70.66%, respectively. There were no significant differences between treatments with biological and chemical insecticides tested in the experiment at 75 and 105 DAA.