Vol

umen

39

•

N

úmer

o 2

Ag

ron

om

ía C

ost

arri

cen

se

Contents

ISSN 0377-9424Versión digital ISSN 2215-2202AGRONOMÍA

COSTARRICENSEVOLUME 39 NUMBER 2 2015

REVISTA DE CIENCIAS AGRÍCOLASUNIVERSIDAD DE COSTA RICA

COLEGIO DE INGENIEROS AGRÓNOMOSMINISTERIO DE AGRICULTURA Y GANADERÍA

www.cia.ucr.ac.cr www.mag.go.cr/rev_agr/index.html

AGRONOMÍACOSTARRICENSE

Biannual journal of agricultural sciencesof the University of Costa Rica,

the Society of Ingenieros Agrónomosand the Ministry of Agriculture

Julio - Diciembre 2015 Volumen 39 Número 2

Scientific papersRelationship between the serological status towards enzootic bovine leukosis and reproductive parameters in specialized dairy herds in Costa Rica.Juan José Romero, Gerardo Dávila, Gabriela Beita and Gaby Dolz . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-18

Fungi that cause postharvest diseases in chayote (Sechium edule (Jacq.) Sw.) and their in vitro control.Siul D. Romero-Velazquez, Bertha Tlapal-Bolaños, Jorge Cadena-Iñiguez, Daniel Nieto-Ángel and Mª. de Lourdes Arévalo-Galarza . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19-32

Genetic diversity among bovine racial subpopulations of Costa Rica.Marco Martínez, Bernardo Vargas, Juan Miguel Cordero, Idania Chacón and Bernal León . . . . . 33-45

Evaluation of silicon, calcium and magnesium in liquid fertilizers on sorghum growth in the greenhouse.Mario A. Araya, Manuel E. Camacho, Eloy Molina and Gilberto Cabalceta . . . . . . . . . . . . . . . . . . 47-59

Effect of Trichoderma spp., Paecilomyces lilacinus and nematicide injection into the pseudostem, on Radopholus similis control and banana production.Randall Vargas, Amy Wang, Miguel Obregón and Mario Araya . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61-76

Risk factors for clinical mastitis in dairy cattle of Costa Rica.María Gabriela Mora, Bernardo Vargas, Juan José Romero and Jorge Camacho . . . . . . . . . . . . . . . 77-89

Asexual propagation bluebush (Justicia tinctoria (Oerst.) D. N. Gibson, Fam. Acanthaceae) by cuttings.Carlos A. Solís, Víctor Jiménez and Julio Arias . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91-103

Risk profile of microbiological and chemical contamination in the production chain of nine horticultural products for fresh consumption of a group of agricultural companies in the Costa Rican Central Valley.Guillermo Vargas-Hernández, Alfredo Durán-Quirós, María Isabel González Lutz and Dennis Mora-Acedo . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105-119

Determining the stages of tillering stage, initiation of primordia, flowering and maturity in the rice plant, with the system S, V and R correlated with the thermal sum at the time.Jennifer Velázquez, Andrea Rosales, Hernán Rodríguez and Rafael Salas . . . . . . . . . . . . . . . . . . 121-129

Technical notesCharacterization of the producers of organic vegetables distributed in the Greater Metropolitan Area (GAM), Costa Rica.Marlen Camacho, Karen Arauz, Natalia Barboza, Héctor A Martínez and Julio Arias . . . . . . . 131-142

Determination of the growth of nematophagous fungi on diverse carbon sources.Martha Orozco A., Ana Jiménez R., Oscar Acuña N. and Víctor Álvarez C. . . . . . . . . . . . . . . . . 143-151

Design of a system to quantify contamination risks and its use in identifying critical control points in horticultural crops in Costa Rica.Guillermo Vargas-Hernández, María Isabel González-Lutz, Alfredo Durán-Quirós and Dennis Mora-Acedo . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153-166