Centro Agrícola

5-9

Authors: Alán Rivero Aragón, Vicente Horacio Grillo Ravelo

Context: Sunflower is the fourth source of vegetable oil in the world. The sunflower moth is its main pest in America. The control of this species is extremely difficult and, generally, the solutions proposed for its control involve the use of insecticides. Objective: To formulate an ecologically sustainable strategy for the control of the sunflower moth. Methods: The insect-host interaction and the damage caused were characterized. The best biological control agents were selected in terms of efficacy. Results: None of the tested cultivars was resistant to Homoeosoma electellum . The perfect timing to protect the sunflower against H. electellum might be estimated between 65 % of the life cycle of the cultivars until reaching the physiological maturity and 84 % until reaching the same phenological state. The application of entomopathogenic bio-preparations significantly reduces the affectation. Conclusions: Treatment with entomopathogenic bio-preparations during the delimited critical interval allows controlling the damage caused to sunflower.

15-19

Authors: Ubaldo Álvarez Hernández, Arahis Cruz Limonte, Ania Villarreal Carrazana, Anialis Almeida Rivero

The aim of the work was to evaluate the effect of integrated management measures on the key pests of tobacco, soybeans and sesame. Three experiments were developed, the first had three treatments: T1. 12 rows of tobacco + 1 row of sorghum +1 row of sunflower, with applications of B. thuringiensis; T2: Monoculture tobacco with applications of insecticides; T3:Absolute control. The soybean and sesame experiments had two treatments each, respectively,Direct Sowing (T1) and Conventional Tillage (T2) and distance between rows of 0.60 m (T1)and 0.80 m (T2). In the three experiments the key pests were evaluated by direct observation according to the methodology described for each case. Polyculture, direct sowing and the shorter distance between rows maintained lower population levels of the key pests in each crop.

24-28

Authors: Rosa Elena González Vázquez, María del Carmen Castellón Valdés, Horacio Grillo Ravelo, Osmany Molina Concepción

Context: Tarophagus colocasiae M. is the most important insect pest in Colocasia esculenta Schott cultivation in Cuba. There are no precedents of its management by entomopathogenic fungi. Objective: To determine T. colocasiaes susceptibility to Metarhizium anisopliae and Beauveria bassiana under laboratory conditions. Methods: T. colocasiaes nymphs and adults were treated with commercial strains of both microorganisms, with an adjusted concentration of 107 spores mL-1. It was determined the mortality at 72, 96 and 120 hours and the average lethal time (TL50). Results: The highest mortality was obtained in the treatment with M. anisopliaeat 120 hours. B. bassiana strain was the most aggressive one, with an average lethal time below 72 hours. Conclusions: T. colocasiaes nymphs and adults are susceptible to entomopathogenic fungi, which provides an encouraging perspective for the implementation of an ecological management strategy.

33-37

Authors: Miriam Díaz Díaz, Alexander Bernal Cabrera, Ricardo Medina Marrero, Divaldo Alfredo Augusto Henriques, Milagros García Bernal

The lemon (Citrus aurantifolia) crop is susceptible to attack by phytopathogens, which are controlled with chemical molecules. An alternative to reverse the ecological damage caused by these chemicals is biological control. The aim of this study was to select strains of actinomycetes with antagonistic activity to Colletotrichum gloeosporioides. It was determined the antagonistic activity in vitro of 181 strains of actinomycetes, belonging to the Chemical Bioactive Center's strain, against C. gloeosporioides; as well as, the extracellular enzymatic activity of the strains that showed better antagonistic effect. From the total of evaluated strains, 62 showed antagonistic capacity manifested against C. gloeosporioides, indicating that they have the potential to be evaluated in vitro and in vivo against different lemon phytopathogens.

43-48

Authors: Silvio de Jesús Martínez MedinaYoel Coello ClaroManuel Díaz CastellanosAlexander Bernal CabreraFelipe Lidcay Herrera Isla43

The study was carried out in the Agricultural Farm "Liberación de Remedios" in the period between December 2018 and April 2019, with the objective of determining the response of commercial cultivars of common bean (Phaseolus vulgaris L.) to the natural infection of Uromyces appendiculatus (Pers.) Unger. Seeds with basic category of cultivars ‘Guama-23̕’, ‘Cuba C 25-9-R’, ‘Delicas-364̕’ and ‘CIAP-24̕’. The incidence percentages, rust severity and the diameter of the pustules were determined. The results indicated that cultivars ‘Delicias 364̔’ and ‘Cuba C 25-9-R’ presented susceptibility to the natural infection of the pathogen, while cultivar ‘CIAP-24̕’ presented moderate resistance and ‘Guama-23̕’ had a resistance response by presenting necrotic spots without reaching the sporulation, so it is recommended to plant it in the late season in the area where the study was carried out.

54-58

Authors: Roberto Valdés Herrera, Yhosvanni Pérez Rodríguez, Marlén Cardenas Morales, Sahily Lozada Reyes, Mayrelis Lavastida Pérez

The experiments were conducted at the Center for Agricultural Research (CIAP) to demonstrate the allelopathic effect exerted by extracts of eight species belonging to the Myrtaceae family on Sitophilus oryzae L. The increase of insects in the mixtures of the grain with powders of the botanical species was calculated. Seven Myrtaceae species exerted an insectistatic effect on S. oryzae. The extracts of the botanical species Pimenta racemosa (Mill.) J.W. Moore also had an insecticidal effect. In the treatments with extracts of Syzygium malaccense L., P. racemosa and Piper auritum Kunth, the insect did not multiply.

63-67

Authors: Lisbeth Morales Díaz de Villegas, Michel Leiva-Mora, Danilo Vera-Coello, Alexander Bernal Cabrera, María Aracely Vera-Loor

The aim of this work was to characterize morphologically, physiologically and molecularly endophytic endospore-forming bacteria associated to Theobroma cacao (cv. Criollo type National) in Quininde canton, Esmeraldas province, Ecuador. The bacteria were characterized from the cultural, morphological and physiological point of view according to methodologies collected in the scientific literature. The confirmation of the identity of the bacteria was made from the sequencing of the gene encoding 16S rRNA. As results, all the strains showed cultural, morphological and physiological characteristics similar to the Bacillus genus. The sequencing confirmed the previous criteria and the main species identified were Bacillus subtilis, Bacillus amyloliquefaciens, Bacillus mycoides and Bacillus cereus with 99 % similarity; while other strains did not produce an optimal consensus sequence, remaining as Bacillus sp.

71-75

Authors: Orelvis Portal, Milady F. Mendoza-Rodríguez, Bárbara Ocaña, Sandra Pérez Pelaez, María I. Oloriz, Monica Höfte

Bananas and plantains are an important source of human food and income for many countries. Among the most important diseases of the crop is the black leaf streak disease (Pseudocercospora fijiensis (Morelet) Deighton). To study the molecular bases of the Musa spp.-P. fijiensis interaction the susceptible cultivar ‘Grande naine’ and the resistant cultivar ‘Calcutta 4’ were used, which were inoculated with a suspension of P. fijiensis under greenhouse conditions. Subtractive libraries of both cultivars were obtained and the gene expression profiles were analyzed by quantitative PCR. Genes related to defense, antioxidants, and jasmonic acid/ethylene and phenylpropanoid pathways were isolated.

80-83

Authors: Orelvis Portal, José Efraín González Ramírez, Dariel Cabrera Mederos, Yaquelin Puchades Izaguirre, Osmany Aday-Díaz

Among the most important diseases in Saccharum spp., sugarcane yellow leaf virus (SCYLV) and sugarcane mosaic virus (SCMV) stand out. In Carica papaya L., papaya ringspot virus (PRSV-P) causes one of the most destructive diseases. The objective of this research was to determine the distribution in Cuba of these viruses and their molecular characterization. Prospecting and molecular diagnosis were carried out by RT-PCR. In the case of SCMV, direct sequencing was performed. Phylodynamic analyzes were performed with 34 sequences from Cuban PRSV-P isolates and 107 sequences from isolates from the American continent and Caribbean islands. SCYLV and PRSV-P are widely distributed in Cuba. From SCYLV the existence of the races BRA-PER, CUB and REU was reported, and from SCMV a single race. The Cuban isolates of PRSV-P and from the American continent and Caribbean islands showed a common ancestor. SCYLV and PRSV-P constitute a potential hazard to farmers.

88-91

Authors: Alexander Bernal Cabrera, Benedicto Martínez Coca, Lidcay Herrera Isla, Belkis Peteira Delgado, Michel Leiva Mora, Yosbel Lazo Roger

Leaf mold, caused by the fungus Cladosporium fulvum (syn. Passalora fulva), is a very common and destructive disease in greenhouse tomato cultivation in the world. The objective of the work was to characterize culturally, pathogenetically and molecularly a population of 36 isolates of C. fulvum from different localities of the country. The results of cultural characterization showed that C. fulvum isolates maintain homogeneous cultural characteristics that are not related to pathogenic variability. From a pathogenetic point of view, the presence of C. fulvum strains that can overcome the Cf-9 resistance gene was demonstrated, a result that was confirmed through the non-amplification of the Avr9 gene. These are the first results in the country on C. fulvum where three of the most important aspects that characterize the variability of this phytopathogenic fungus are combined.