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Abstract Plant-induced resistance can be an important component of soybean mites biological control programs. This work evaluates the preference of predatory mite Neoseiulus californicus (Acari: Phytoseiidae) to soybean plants under single and multiple herbivory conditions by two-spotted spider mite Tetranychus urticae (Acari: Tetranychidae), and velvetbean caterpillar Anticarsia gemmatalis (Lepidoptera: Noctuidae). Using a Y olfactometer, the following scenarios were evaluated: soybean with no infestation and soybean infested with A. gemmatalis; soybean infested with T. urticae and A. gemmatalis, and soybean infested with T. urticae and with both T. urticae and A. gemmatalis. Volatile compounds released by plants were analyzed and identified by a Trace GC Ultra gas chromatograph coupled to a mass spectrometer with a solid phase micro-extraction ion-trap. The predatory mite N. californicus preferred soybean plants infested with T. urticae compared to those infested with A. gemmatalis. Multiple infestation did not interfere with its preference to T. urticae. Multiple herbivory of T. urticae and A. gemmatalis modified the chemical profile of volatile compounds emitted by soybean plants. However, it did not interfere with the search behavior of N. californicus. Out of the 29 identified compounds only five promoted predatory mite response. Thus, regardless of single or multiple herbivory by T. urticae with or without A. gemmatalis, the indirect induced resistance mechanisms operate similarly. As such, this mechanism contributes to an increase in the encounter rate between predator and prey for N. Californicus and T. urticae, and the efficacy of biological control of mites on soybean.

Abstract The lower lignin content in plants species with energy potential results in easier cellulose breakdown, making glucose available for ethanol generation. However, higher lignin levels can increase resistance to insect attack. The objective of this work was to evaluate the susceptibility of a bmr-6 biomass sorghum (a mutant genotype with a lower concentration of lignin) to important pests of energy sorghum, Diatraea saccharalis and Spodoptera frugiperda. Experiments were performed in the laboratory and greenhouse to evaluate the development of these pests on the biomass sorghum bmr hybrids BR007, BR008, and TX635 and their respective conventional near-isogenic genotypes (without the bmr gene). The lignin content was higher in non-bmr hybrids, but the evaluated insect variables varied between treatments, not being consistent in just one hybrid or because it is bmr or not. The lowest survival of S. frugiperda was observed in the BR008 hybrid, both bmr and non-bmr. The S. frugiperda injury scores on plants in the greenhouse were high (>7) in all treatments. For D. saccharalis, there was no difference in larval survival in the laboratory, but in the greenhouse, the BR007 hybrid, both bmr and non-bmr, provided greater survival. Due the need to diversify the energy matrix and the fact that greater susceptibility of the bmr hybrids to either pests was not found in this study, these results hold promise for cultivation of these biomass sorghum hybrids for the production of biofuels.

Abstract Among the plants defense mechanisms, the induction and emission of volatile organic compounds, which can be used to attract natural enemies, such predators insects. Although well studied, the induction of plant volatiles that attract natural enemies can vary according to intensity of infestation of herbivores and the species of host plant. We investigated the olfactory behavioral responses of the predatory mite Neoseiulus californicus (McGregor) (Acari: Phytoseiidae) to the volatiles of infested maize (Zea mays) plants by the two-spotted spider mite Tetranychus urticae (Koch, 1836) (Acari: Tetranychidae) in early and advanced infestations. The Bt (Viptera) maize cultivar Impact® was used for tests the behavior of N. californicus. After initial and advanced infestations, the phytophagous mites T. urticae were removed, and the plants were tested using a “Y” olfactometer. The following treatments were evaluated: air vs. air, uninfested plants vs. air, uninfested plants vs. plants infested with 10 females of T. urticae, uninfested plants vs. plants infested with 100 females of T. urticae, uninfested plants vs. plants infested with 200 females of T. urticae and plants infested with 10 vs. plants infested with 200 females of T. urticae. The predatory mite N. californicus did not show preference to the treatments tested, suggesting that maize plants infested by T. urticae do not induce volatiles capable of attracting the predatory mite N. californicus. We concluded that N. californicus is not attracted by maize plants infested by T. urticae.

Abstract Understanding the ecological and toxicological relationship between genetically modified cultivars (GM) and biological control agents is of great importance for discussions related to the compatability of GM cultivars and integrated management strategies for pest resistance. The present study evaluated the search behavior and predatory capacity of Orius insidiosus (Say) (Hemiptera: Anthocoridae) and Doru luteipes (Scudder) (Dermaptera: Forficulidae) on eggs and caterpillars of Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) resistant or not to the protein Cry1F expressed in Bt corn. To determine the search time, a stopwatch was run until the capture of the first prey, predation capacity was evaluated by counting the prey remaining after 24 hours of infestation. The injuries of S. frugiperda in genetically modified and conventional corn in the presence and absence of predators was also evaluated. The predators were not able to distinguish between resistant and susceptible prey (eggs or caterpillars), given the predatory behaviour observed. There was no difference in searching time or predatory capacity between the predators for eggs and caterpillars of either resistant or susceptible S. frugiperda. In the presence of predators, the injury scores for resistant S. frugiperda on the Bt corn plants were lower. It was concluded that O. insidiosus and D. luteipes did not notice the presence of the protein Cry1F in the prey S. frugiperda, which may facilitate the combined use of GM corn and biological control in integrated management programs and for management of pest resistance.

Abstract In Brazil, the expansion of agricultural activity and the associated indiscriminate use of herbicides such as glyphosate is directly related to the loss of biodiversity in the Cerrado. The identification of plant species as bioindicators of herbicide action, especially species native to the area, can help in monitoring the impacts of xenobiotics in the remaining Cerrado. Thus, this study was designed to evaluate the possible use of the native Cerrado species Pouteria torta as a bioindicator of glyphosate action via changes in physiological performance. At 16 months after sowing, the effect of glyphosate was evaluated by applying the following doses: 0 (control), 25, 50, 100, 200, 400, 800, and 1200 g a.e. ha-1. In response to glyphosate, P. torta exhibited reductions in photosynthesis and chloroplastid pigment content, as well as accumulation of shikimic acid and the occurrence of chlorosis and necrosis. These changes demonstrate the high sensitivity of P. torta to glyphosate and its potential for use as a bioindicator of this herbicide.

O objetivo deste estudo foi avaliar a composição florística e estrutural do estrato arbóreo de um remanescente de mata atlântica submontana na Região do Imbé, RJ, testando a hipótese de que diferenças em altitude (zona 1 localizada a 50m.s.m. e zona 2 localizada a 250m.s.m.) acarretam alterações na comunidade. O total de dez parcelas de 30×40m foram alocadas em duas zonas altitudinais, cinco no sítio 1 e outras cinco no sítio 2. Todas as árvores com DAP > 10cm foram marcadas e medidas. Dentre os 940 indivíduos amostrados, um total de 210 espécies foram identificadas, distribuídas em 158 gêneros e 43 famílias. As duas zonas estudadas apresentaram valores semelhantes de densidade total, área basal total e diversidade de espécies. Os valores de diversidade de espécies estão entre os mais altos encontrados em Mata Atlântica. A família Euphorbiaceae apresentou os maiores valores de VC em ambas as zonas altitudinais. A família mais rica em número de espécies foi Leguminosae (26 espécies). Das 210 espécies amostradas, apenas 57 foram comuns às duas zonas amostradas. Na zona 1, as espécies com os maiores VC foram Hyeronima alchorneoides Allemão (14,3), Actimostemon verticilatus (Kl.) Baill. (11,4) e Rustia formosa (Cham. & Schltal.) Klotzch (10,7), enquanto que para a zona 2, foram Actimostemon verticilatus (13,8), Euterpe edulis Mart. (12,4) e Mabea fistulifera Mart. (8,1). Os resultados indicaram que a composição florística mudou em função da altitude, mas não a estrutura da floresta e a diversidade de espécies.The Imbé is one of the main Atlantic forest remnants in the Rio de Janeiro State. The aim of this study was to test whether differences in forest structure and floristic composition exist between two tree communities at different altitudes (site 1 at 50m high and site 2 at 250m high). Five plots of 30m×40m (1200m²) were setup in each site. All trees with DBH > 10cm were tagged and measured. A total of 210 species was sampled, distributed in 158 genus and 43 families. Both sites is showed similar values for basal area, number of individuals and canopy height. The species diversity (H'= 4,21 and 4,30, respectively to site 1 and site 2) can be considered to be within the highest values found for Atlantic forests. Among the families, the Euphorbiaceae had the highest values of CV in both altitudinal sites. The family with the highest richness of species was the Leguminosae (26 species). Only 57 species were common to both forest sites. At site 1, the species with the highest CV were Hyeronima alchorneoides Allemão (14,3), Actimostemon verticilatus (11,4) and Rustia formosa (Cham. & Schltal.) Klotzch (10,7), while for the forest at site 2 they were Actimostemon verticilatus (Kl.) Baill. (13,8), Euterpe edulis Mart. (12,4) and Mabea fistulifera Mart. (8,1). The results showed that the floristic composition changed with altitude, but not the forest structure and species diversity.

Previous surveys conducted in commercial nurseries found that different wood fungi, namely Cylindrocarpon spp., Botryosphaeriaceae, Phomopsis viticola and Phaeomoniella chlamydospora infect grapevine cuttings. Two field trials were carried out to evaluate the effectiveness of cyprodinil + fludioxonil, pyraclostrobin + metiram, fludioxonil and cyprodinil to prevent or reduce natural infections caused by such fungi. Rootstock and scion cuttings were soaked in fungicidal suspensions for 50 min prior to grafting. After callusing, the grafted cuttings were planted in two commercial field nurseries with and without a previous history of grapevine cultivation. After nine months in the nursery, the plants were uprooted and analysed for the incidence and severity of the wood fungi. Plants uprooted from the field without a previous history of grapevine cultivation were generally less strongly infected by wood fungi. Under this condition, only the mixture cyprodinil + fludioxonil simultaneously reduced the incidence of Cylindrocarpon and Botryosphaeriaceae fungi, as well as the severity of Cylindrocarpon infections. Treatments did not produce significant differences in the incidence and severity of P. viticola, and Pa. chlamydospora. For plants grown in the field with a grapevine history, all fungicides except cyprodinil significantly reduced the incidence and severity of Cylindrocarpon fungi. Also, the incidence and severity of Botryosphaeriaceae pathogens were significantly decreased both by cyprodinil + fludioxonil and by cyprodinil. No significant differences were noticed for P. viticola incidence and severity, and Pa. chlamydospora was not detected again. These results suggest that the practice of soaking grapevine cuttings in selected fungicides prior to grafting significantly reduces Cylindrocarpon spp. and Botryosphaeriaceae infections, thus improving the quality of planting material.

Black foot disease of grapevine is caused by Cylindrocarpon spp., with C. destructans being the main pathogen isolated from vine cuttings and young vineyards in Portugal. Few recommendations for black foot disease control are presently available, and they are not easy to implement within commercial nurseries. In this study, 14 fungicides were evaluated for their effect on the mycelial growth and conidium germination of four field isolates of C. destructans. Mycelial growth of the pathogen was inhibited by DMI fungicides, prochloraz (EC50 values

Foi estudada a vegetação de restinga do complexo lagunar Grussaí/Iquipari (21°44'S; 41°02'O), que compreende a bacia das lagunas de Grussaí e Iquipari, com aproximadamente 4.800ha. Uma transecção de 25ha (2500x100m) foi delimitada no sentido mar/interior e coletas botânicas realizadas entre os anos de 1995 e 1997. As quatro unidades fisionômicas ocorrentes na área foram estudadas e, através do Índice de Valor de Cobertura, foram determinadas as espécies dominantes em cada formação: 1) Formação Praial-Graminóide: Remirea maritima, Ipomoea imperati, Sporobolus virginicus e Chamaecyse thymifolia; 2) Formação Praial com Moitas: Schinus terebinthifolius, Eugenia sulcata, Pilosocereus arrabidae e Cereus fernambucensis; 3) Formação de Clusia: Pera glabrata, Eugenia sulcata, Sideroxylon obtusifolium e Scutia arenicola; 4) Formação Mata de Restinga: Maytenus obtusifolia, Pera glabrata, Protium heptaphyllum e Coccoloba alnifolia. A similaridade florística da área estudada com outras restingas nos Estados do Rio de Janeiro e Espírito Santo não ultrapassou 41%, onde a proximidade geográfica não representou aumento da similaridade. Os resultados ressaltam a variação da flora de restinga ao longo de um pequeno trecho do litoral brasileiro.

Due to its fungistatic or fungicidal potential, chitosan, a high molecular-weight polymer that is non-toxic and biodegradable, has become an alternative to conventional fungicides. In addition, chitosan is reported to elicit defense mechanisms in plant tissues. In this study, we explored the in vitro fungicidal effect of chitosan on some of the most important grapevine wood fungi, such as Botryosphaeria sp. (dieback and cane blight), Phomopsis sp. (Phomopsis cane and leaf spot), Eutypa lata (eutypa dieback), Neonectria liriodendri (black foot disease), Phaeomoniella chlamydospora (Petri disease and esca) and Fomitiporia sp. (esca). Inhibition of mycelial growth was evaluated at five concentrations 50, 25, 5, 2.5 and 0.5 mg a.i. l-1 of chitosan. Chitosan was effective in reducing mycelial growth of all the fungi. The lowest EC50 values were obtained with Pa. chlamydospora, Fomitiporia sp. and Botryosphaeria sp., and the highest with Neon. liriodendri. All these were inferior to the maximum recommended field rate (8.33 mg a.i. l-1) with exception of the value obtained with Neon. liriodendri. Greenhouse experiments were carried out to evaluate the efficacy of foliar sprays of chitosan on potted grapevine plants (cultivar Castelão) growing in a substrate artificially infested with Pa. chlamydospora or Neon. liriodendri. The effect of chitosan against Neon. liriodendri was similar to that achieved with some selected fungicides (carbendazim+flusilazole, cyprodinil+fludioxonil and tebuconazole). Chitosan significantly improved plant growth (plant height and number of roots) and decreased disease incidence compared with untreated plants. As regards Pa. chlamydospora, chitosan only reduced the disease incidence caused by this fungus.