Luciana Gonçalves de Oliveira

O cultivo da palma no semiárido brasileiro cresce devido à sua alta produtividade, resistência climática e adaptação a ambientes áridos. Apesar de estudos sobre sua produtividade, há pouca investigação sobre o impacto das características morfológicas na diversidade fenotípica e desempenho agronômico da mesma. A variação entre gêneros e espécies ressalta a importância da caracterização fenotípica e catalogação do germoplasma para o melhoramento genético. Este estudo caracterizou morfologicamente acessos de palma forrageira dos gêneros Opuntia e Nopalea do Banco Ativo de Germoplasma do IPA. O experimento foi realizado em Arcoverde-PE, avaliando 80 acessos conforme descritores da cultura. A análise comparativa revelou significativa diversidade fenotípica, com variações morfológicas interligadas impactando a dissimilaridade entre acessos. Para Nopalea, a Análise de Componentes Principais (PCA) explicou 72% da variabilidade dos dados, separando os acessos em três grupos distintos. Enquanto Opuntia, a PCA explicou 40,1% da variabilidade, formando oito grupos e evidenciando maior diversidade. Os acessos de Nopalea apresentaram estrutura fenotípica mais homogênea, em contraste Opuntia mostrou maior variação. Desta forma, as 15 características morfológicas utilizadas foram eficazes na discriminação dos acessos, demonstrando a relação entre variabilidade morfológica e estrutura genética. A análise de caracteres quantitativos revelou padrões fenotípicos associados a grupos genéticos e adaptação local, contribuindo para futuras estratégias de melhoramento genético da palma forrageira.

The common bean (Phaseolus vulgaris L.) is crucial for human nutrition, providing proteins and essential nutrients to millions of families globally. This crop faces significant challenges from diseases caused by phytopathogenic fungi like Macrophomina phaseolina and Fusarium spp.. Trichoderma sp. is known for its ability to produce secondary metabolites with antagonistic properties against various phytopathogens. This study aimed to evaluate the antagonistic potential of volatile and non-volatile metabolites produced by Trichoderma in inhibiting the mycelial growth of Macrophomina phaseolina, Fusarium triseptatum, Fusarium annulatum, and Fusarium fabacearum. Tests involved three Trichoderma species (T. asperelloides, T. asperellum, and T. afroharzianum). Volatile metabolites were tested using the double plate method, while non-volatile metabolites were assessed by incorporating Trichoderma filtrate into 25% Potato Dextrose Agar (PDA), with the pathogen placed in the Petri dish center. Results demonstrated that both types of metabolites effectively controlled phytopathogens, with T. asperelloides (URM8945 and URM8946) showing notable inhibition of M. phaseolina isolates, and T. asperellum (URM8998) and T. afroharzianum (URM8938) exhibiting activity against F. annulatum. Volatile compounds were generally more effective against Fusarium spp. isolates compared to non-volatile metabolites. Therefore, metabolites from these Trichoderma species should be considered for sustainable disease management in common bean crops.

Trichoderma is an important fungal genus, known mainly for its potential for the biological control of phytopathogens. Accurate identification of these fungi is essential for research and applications involving them, to be addressed correctly. The objectives of this study were to isolate, identify, and report the species richness of Trichoderma species that occur in the soil of different regions of Pernambuco, Brazil. DNA sequences of portions of the translation elongation factor 1-α (TEF1) gene region were generated for 56 isolates of Trichoderma, obtained from the Zona da Mata, Agreste, and Sertão regions of Pernambuco. According to the phylogenetic analysis based on these sequences, these fungi belong to two Sections—Trichoderma (35 isolates) and Pachybasidium (21 isolates). These fungi have been resolved in nine species, including Trichoderma afroharzianum, Trichoderma asperelloides, Trichoderma asperellum, Trichoderma koningiopsis, and five possible new species to be confirmed in further studies. This study shows that the soils of Pernambuco host a diversity of Trichoderma species and consequently of biological resources with potential for application in agriculture.

Nasutitermes corniger is an arboreal termite that causes economic damage in urban areas, and its control is for chemical insecticides. An alternative for insect control is the use of entomopathogenic fungi and plant extracts, or the synergistic effect of the association of these. The toxicity of aqueous and hydroethanolic extracts of Agave sisalana on the biological aspects of the fungal Cordyceps farinosa, C. fumosorosea and C. javanica and the action of the extracts and their synergistic effect on N. corniger was examined. The effect of the extracts on fungi was evaluated by germination, sporulation and mycelial growth of fungi in Sabouraud medium through the study of biological aspects under laboratory conditions; and control of N. corniger were examined, by ingestion of extracts and of the association extract plus fungus on filter paper, being the percentage of mortality of soldiers and workers of the termite daily. In general, the extracts were inoffensive to the fungi at concentrations 10, 25, 50, 100 and 200 mg.mL ⁻¹ . The extracts demonstrated termiticidal actions at concentrations tested, causing the mortalities about 100% of the workers after the third and sixth days (LC ₅₀ : 0.778 to 0.803 mg.mL ⁻¹ ) and 100% of the soldiers between the fourth and seventh days (LC ₅₀ :0.146 to 0.956 mg.mL ⁻¹ ). The association of the extracts with C. farinosa ESALQ1355 was more efficient in inducing the mortality in N. corniger. These results demonstrated the efficiency in vitro of the sisal extracts in controlling N. corniger termites, alone or in combination with fungi, suggesting their potential joint usefulness in the biological control of insect pests.

AÇÃO ANTAGÔNICA À Macrophomina phaseolina e Fusarium oxysporum E DIVERSIDADE GENÉTICA DE BACTÉRIAS OBTIDAS DE SOLO CULTIVADO COM Vigna unguiculata (L.) Walp)

Nasutitermes corniger (Motschulsky) is an urban termite pest that is controlled by chemical applications. We investigated the effect of the association of Isaria farinosa (Holm: Fries) Fries, I. fumosorosea (Wize) Brown & Smith, and I. javanica (Frieder & Bally) Samson & Hywell-Jones with the extracts of Libidibia ferrea var. ferrea (Mart. Ex Tul.) L. P. Queiroz in the control of N. corniger. The following experiments were performed: the toxicity of aqueous and methanolic extracts on the biological aspects of fungi, action of extracts on workers and soldiers, and fungus-extract combination on workers of termite. The aqueous extracts of the leaves and pods of L. ferrea var. ferrrea were more efficient than the methanol extracts, demonstrating termiticide activity at 10, 25, 50, 100, and 200 mg mL-1, with 100% worker mortality after the third and fourth days and 100% soldier mortality by the third through sixth day. Lethal concentrations (LC50) varied from 0.624 to 0.710 mg mL-1 for workers and from 0.146 to 1.410 mg mL-1 for soldiers. The extracts were compatible with the fungal strains at the lowest concentrations. Associations of the extracts with I. farinosa ESALQ1355 demonstrated efficient control of termite workers. The results demonstrate that L. ferrea var. ferrrea extracts, either alone or in association with I. farinosa ESALQ1355, functioned in the in vitro control of N. corniger, representing a viable alternative to be further tested in controlling those termites in urban areas.

Opuntia ficus-indica is a cactus used as fodder for animals in arid areas worldwide. However, the palm is parasitized by the carmine cochineal scale insect (Dactylopius opuntiae) causing great damage to cactus plantations in the semi-arid region of Brazil. Leaf extracts aqueous and hydro-ethanolic of neem and citronella at concentrations of 50, 100 and 200 mg/mL, and strains suspensions of Beauveria bassiana (1 × 108 conidia/mL); were applied on cladodes infested by D. opuntiae, in the laboratory. After 10 days of treatment, the percentages of mortality were obtained on the adult females. Then, the most efficient extracts were selected in the laboratory tests for control tests in palm plantation, where 100 mL of the extracts were applied in the 100 mg/mL concentration on cladodes of palms. The results show that B. bassiana strains were not pathogenic to D. opuntiae. Only the aqueous and hydro-ethanolic neem extracts were effective in controlling the cochineal. We conclude that neem extracts are effective against D. opuntiae and can be used to control carmine scale in Opuntia ficus-indica in the field.

We analyzed the activity of the entomopathogenic fungi Isaria farinosa, I. fumosorosea and I. javanica against the cochineal Dactylopius opuntiae, as well as the effects of the insecticides clorpirifos, acetamiprid, thiamethoxam and lambda-cyhalothrin on the conidia germination, mycelium growth and a sporulation of the fungi. These fungi were not pathogenic to cochineal. This the first report of the efficiency of Isaria spp. against this the insect. The bioassays of the compatibility of the insecticides acetamiprid and thiametoxam with species of Isaria indicate the possibility of the joint use of these products in studies on the control of D. opuntiae.

Cowpea crops have the highest social and economic relevance to Brazil, being the food base of families mainly in the semi-arid areas of the country. Charcoal rot caused by Macrophomina phaseolina is an economically important disease of cowpea that can cause significant reductions in bean yield. This study aimed to access the genetic diversity of M. phaseolina isolates obtained from cowpea grown in the Pernambuco semi-arid region, by molecular analysis. Fifty-one isolates, collected from municipality of Belém do São Francisco from cowpea plants and displaying typical symptoms and signs of charcoal rot, were studied using inter-simple sequence repeat (ISSR) markers. Unweighted pair-group method using arithmetic means (UPGMA) clustering of data showed that isolates clearly differentiate into two groups. The group 1 comprises the majority of isolates and the group 2 contains two isolates, isol46 and isol47. The highest similarity index (0.9) was observed between the isolates isol22 and isol35 and the lowest similarity index (0.2) was observed between isol37 and isol46 isolates. Our results revealed that the ISSR-PCR fingerprinting patterns were useful for differentiating M. phaseolina isolates from V. unguiculata plants sampled. Therefore, genetic characterization of this fungus is of importance for the effective disease management.