Aristides Armstrong | University of Puerto Rico Mayaguez (original) (raw)

Papers by Aristides Armstrong

Journal of Agriculture of The University of Puerto Rico, Oct 1, 1987

Journal of Agriculture of The University of Puerto Rico, Dec 1, 2012

para determinar el comportamiento agronómico de cuatro genotipos de maíz. El objetivo de esta inv... more para determinar el comportamiento agronómico de cuatro genotipos de maíz. El objetivo de esta investigación fue determinar los coeficientes genéticos de tres cultivares locales de maíz: 'Mayorbela' (M), 'Diente de Caballo' (DC), 'Chulo' (Ch) y de un híbrido transgénico de Pioneer Hi-Bred International, Inc. (híbrido Pioneer) para utilizarlos en el modelo CERES-Maize para predecir el comportamiento de estos genotipos bajo condiciones tropicales. Se determinaron los coeficientes genéticos para el crecimiento y desarrollo del maíz, los cuales incluyeron: duración de la fase juvenil del cultivo (P1), duración de la fase de acumulación de materia seca en el grano (P5), número potencial de granos por mazorca (G2), y crecimiento diario lineal del grano (G3). El crecimiento del cultivo se expresó utilizando el concepto de unidades termales (Td). Además, se estimaron otras variables de crecimiento tales como índice de área foliar y biomasa total acumulada. Se establecieron dos experimentos

Journal of Agriculture of The University of Puerto Rico, Dec 31, 1969

En Puerto Rico existen 20 especies de hornópteros y hemípteros asociados al cultivo de la papaya ... more En Puerto Rico existen 20 especies de hornópteros y hemípteros asociados al cultivo de la papaya (Carica papaya L.). Entre los hornópteros están los cicadélidos Empoasca papayae Ornan, Empoasca dilitaña DeLong y Davidson, Empoasca canavalia DeLong y Empoasca insularis Ornan (Cook, 1931; Martorell, 1976). Sin embargo, se desconoce la distribución geográfica de las especies de Empoasca asociadas a la papaya en la isla, y no está claro cuál es la especie predominante en este cultivo. En Puerto Rico se ha reportado a E. papayae como vector principal del cogollo racimoso, una enfermedad importante de la papaya (Martorell y Adsuar, 1952), En otros países se han reportado como vectores del cogollo racimoso a E. düUaria y E. stevensi Young (Haque y Parasram, 1973; Martorell y Adsuar, 1952), Con el objetivo de confirmar las especies de Empoasca asociadas al cultivo de la papaya y determinar la especie de mayor predominancia se realizó un catastro entre junio de 1995 y marzo de 1996 en diferentes áreas de Puerto Rico. Para tal fin se visitaron 19 siembras de papaya en fincas

Journal of Agriculture of The University of Puerto Rico, Apr 1, 1994

During 1988-89 Spodoptera sunia larvae were found attacking cabbage (Brassica olerácea var. capit... more During 1988-89 Spodoptera sunia larvae were found attacking cabbage (Brassica olerácea var. capita (a L.) in experimental plots at the Puerto Rico Agricultural Experiment Station in Fortuna at Juana Díaz, PR. Plots consisted of 28 cabbage genotypes, 14 of which were attacked.

Journal of Agriculture of The University of Puerto Rico, Dec 31, 1969

Three field trials with cabbage var. Market Prize were established at the Isabela Substation, AES... more Three field trials with cabbage var. Market Prize were established at the Isabela Substation, AES-UPR, to evaluate the susceptibility of Plutelfa xylostella to various insecticides. Dosages recommended by the manufacturer were used for the first two applications in the first trial, and some double dosages were included in an attempt to get at least a 90% control of the larvae population. For the other two trials, recommended dosages and the effective higher dosages from the first trial were compared. Significant differences were obtained with methamidophos {2.34 L/ha), permethrin (0.234 and 0.468 l/ha), and fenvalerate (0.35 L/ha) for controlling the larvae. Control figures for those four treatments were 97.8, 100, 100, and 99.9%, respectively. Methamidophos, acephate, and naled controlled over 90% of the larvae only with double the recommended rates. Chlorpyrifos at 1.17 L/ha was ineffective, but at its higher rate controlled 80 to 90% of the larvae. Diazinon, methomyl, dimethoate, and endosulfan even at their highest rates were ineffective for controlling the larvae. The number of larvae increased after each application of these insecticides. The greatest numbers of marketable heads were obtained from plots treated with permethrin, fenvalerate, and methamidophos at the highest rate for each, RESUMEN

Journal of Agriculture of The University of Puerto Rico, Oct 1, 1987

Journal of Agriculture of The University of Puerto Rico, Apr 1, 2011

Sweet corn (Zea mays L.) is a popular food in Puerto Rico. This high-value horticultural crop can... more Sweet corn (Zea mays L.) is a popular food in Puerto Rico. This high-value horticultural crop can be successfully cultivated by using different levels of technology, ranging from mechanized production for processing to plantings on small-scale farms where sweet corn can be intercropped with other high value crops such as tropical pumpkin {Cucúrbita moschata Duch. ex Lam.) or pole snap beans (Phaseolus vulgaris L.).

Journal of Agriculture of The University of Puerto Rico, Dec 31, 1969

Two field plantings were established at Isabela (AES-UPR) (27 August 1984) to evaluate 27 genotyp... more Two field plantings were established at Isabela (AES-UPR) (27 August 1984) to evaluate 27 genotypes (15 early bloomers and 12 late bloomers) for resistance to pod borer, Heliothis virescens and Btiella zinckenelh. One planting of the 27 genotypes was treated with methomyl 90S (0.56 kg/ha). The second planting was untreated, insecticide applications began at the flowering stage. The efficacy and resistance data were based on the number of larvae and damaged pods per plot ai harvest. Eggs of H. virescerts per pod per plot were counted. None of the untreated early bloomers tested were free from pod borer attack. The most tolerant genotypes were lines 82-26-1 and 82-1-24 Ponce 83, with 19 and 28% damaged pods, respectively. The most susceptible was line 69-73-1-B-D with 57% damaged pods. At harvest, genotypes 82-3-16, 29 Irradiado, 79 Irradiado, 99-1 Irradiado and 69-73-1-B-D were free or almost free of E. zinckenelh larvae. Methomyl-treated early bloomer genotypes showed lower percentages of infestation. Line 69-73-1-B-D showed only 7% damaged pods. The most susceptible, with 55% damaged pods, was line 82-29. All the untreated late bloomer genotypes were attacked by pod borer larvae. Lines 69-68 and 7 had the best ratings with 21 and 24% damaged pods, respectively. Cultivar Amarillo Kaki was the most susceptible, with 57% damaged pods. At harvest, H. virescens larvae was more dominant except for lines 87-7 Ponce 83 and cv. Santa Isabel, where E. zinckenetla larvae were more abundant, Methomyl-treated plants of the late bloomers showed lower percentages of damaged pods. Line 12 and cv. Amarillo-Kaki 1 each showed 11% damaged pods. Cultivar Santa Isabel and lines 82-7 Ponce and 77-1 Irradiado were the most susceptible.

Journal of Agriculture of The University of Puerto Rico, Dec 31, 1969

Light trap studies on population abundance of Heliothis virescens and Etiella zinckenella on diff... more Light trap studies on population abundance of Heliothis virescens and Etiella zinckenella on different stages (bloom and pod formation) of pigeon pea were conducted during the growing seasons of 1984, 1985 and 1986. Cultivare Kaki and 2B-Bushy were used. Heliothis virescens was more abundant than E. zinckenella. Both species were detected at the bloom stage, but H. virescens predominated at the bloom and pod formation stage, indicating an early infestation. At the dry pod stage, adults of f, zinckenella were noticeable when the pods approached maturity (full pod stage) reaching a peak number during the dry pod stage. Both pod borers were more abundant at the harvest period (green pods). It is suggested that overlapping generations of both species and their life cycles are synchronous with the phenology of the crop. RESUMEN Heliothis virescens y Etiella zinckenella capturados en trampas lumínicas en gandulares En 1934, 1985 y 1986 se hicieron estudios con trampas ¡umínieas para establecer preliminar men te si había Heliothis virescens y Etiella zinckenella en las diferentes etapas de desarrollo del gandul (floración y formación de la vaina). Se sembraron las variedades Kaki y 2B-Bushy. Los resultados indican que H. virescens es más predominante que E. zinckenella. Aunque ambas especies se detectaron en la etapa de florecida, H. virescens se capturó en mayor número durante las etapas de floración y formación de la vaina. Los adultos de f. zinckenella se capturaron en mayor número cuando las vainas estaban ya maduras alcanzando su número máximo durante la etapa de vainas secas. Ambas especies de barrenadores se capturaron en gran número durante la época de cosecha (vainas verdes). Se sugiere una posible sobreposición de generaciones de ambas especies coincidiendo con una mayor abundancia en la cosecha y una sincronía de los ciclos de vida de estos insectos con la fenología del cultivo.

Journal of Agriculture of The University of Puerto Rico, 1990

The Journal of Agriculture of the University of Puerto Rico, 1969

La mosca asiática del gandul, Melanagromyza obtusa (Malloch) se detectó en Puerto Rico por primer... more La mosca asiática del gandul, Melanagromyza obtusa (Malloch) se detectó en Puerto Rico por primera vez en 1999.

The Journal of Agriculture of the University of Puerto Rico, 1969

Two parasitoid species (Catolaccus hunteri and Urosigalphus mexicanus) were recovered from the la... more Two parasitoid species (Catolaccus hunteri and Urosigalphus mexicanus) were recovered from the larvae of A. eugenii from samples collected at Lajas, Puerto Rico.

The Journal of Agriculture of the University of Puerto Rico, 1969

The effeciveness of several insecticides and nematicide-insecticides in the control of aphids, mi... more The effeciveness of several insecticides and nematicide-insecticides in the control of aphids, mites and nematodes in pepper cultivars Cubanelle and Blanco del País was determined in four field experiments in 1979, 1980 and 1981 at lsabela, Puerto Rico. In the first test, a significant control of the green peach aphid Myzus persicae was obtained, 48 h and 1 month after application. In the second test, the oxamyl L-treated plots were the least affected by pepper mite. In these plots some reduction in nematode population levels, especially in Rotylenchulus reniformis, was obtained. Highest yield increases of pepper cv. Cubanelle were obtained with 1.12 kg/ha of oxamyl L (46%), 1.68 kg/ha of aldicarb (41%), and 0.56 kg/ha of oxamyl (40%). In the third test, Blanco del País plants treated with oxamyl showed no mite damage, a normal stand, and the highest yields, as well as good nematode control. Plant stand from methamidophos-treated plots was similar to that of control plants although ...

The Journal of Agriculture of the University of Puerto Rico, 1969

Se determinó el ciclo de vida del piche de la batata, Cylas formicarius var. elegantulus, bajo co... more Se determinó el ciclo de vida del piche de la batata, Cylas formicarius var. elegantulus, bajo condiciones de laboratorio en Puerto Rico. Se observaron todas las etapas de desarrollo del insecto y se determinó la duración de cada una. El ciclo de vida tuvo la siguiente duración media en días para cada etapa: huevo, 7,7; larva, 28.0; pupa 7.2; preadulto, 4.4; adulto 42.5. El ciclo de vida de huevo a adulto tuvo una duración media de 47.3 días.

The Journal of Agriculture of the University of Puerto Rico, 1969

Two field experiments were undertaken in Puerto Rico, one in Isabela and another in Mayagüez, to ... more Two field experiments were undertaken in Puerto Rico, one in Isabela and another in Mayagüez, to determine the susceptibility of several cultivars of Ipomoea batatas (L.) (Lam.) to Cylas formicarius var. elegantulus (Summers). Although the total yield of the cultivars was not affected by the initial injuries caused by the insect, the quality of the tuber was affected in both experiments. The degree of susceptibility in each experiment was determined from the internal damage and the number of larvae in the tubers. In Isabela, cultivars WRAS-3, WRAS-7, WRAS-31, WRAS-36, Mojave and Gem were highly susceptible to the weevil attacks, whereas varieties Regal and Sumor and the WRAS-7 line were moderately susceptible. In Mayagüez cultivars WRAS-36, Mojave, Miguela and Gem were highly susceptible to the attack of the insect. Cultivars WRAS-3, WRAS-7, Resisto, Sumor, WRAS-25, WRAS-31, WRAS-35, were moderately susceptible. Variety Regal and the WRAS-37 and WRAS-40 lines were the most resistant...

The Journal of Agriculture of the University of Puerto Rico, 1969

NUEVO HOSPEDERO ALTERNO DEL PICUDO DEL PIMIENTO, ANTHONOMOUS EUGENII CANO EN PUERTO RICO

The Journal of Agriculture of the University of Puerto Rico, 1969

Se realizaron dos ensayos de campo de pimiento var. Cubanelle (trasplantadas el 22 de abril de 19... more Se realizaron dos ensayos de campo de pimiento var. Cubanelle (trasplantadas el 22 de abril de 1985) en la Estación Experimental Agrícola en Isabela para evaluar insecticidas para el control del picudo del pimiento, Anthonomus eugenii Cano. En el primer ensayo se evaluaron los insecticidas permetrina 2E a razón de 0.23 y 0.47 U ha, oxamilo L a razón de 2.34 y 4.68 L/ha y fenvalerato 2.3 EC a razón de 0.39 y 0.78 L/ha. En el segundo ensayo sólo se evaluó el fenvalerato a las dosis ya señaladas. Todas las aplicaciones foliares se realizaron con una bomba de espalda; se empezaron cuando la fruta ya se estaba formando y se continuaron semanalmente. La eficacia se determinó a base del número de frutos caídos por parcela. Se obtuvieron diferencias significativas con fenvalerato (0.78 L/ha), cuyo número de frutas caídas por parcela (10.07) fue el menor. Con 90% de control y 31% mostró el menor porcentaje de pérdidas. Con oxamilo a razón de 4.68 una se logró 79% de control y el segundo núme...