SUSCEPTIBILITY OF 7 CULTIVARS OF COFFEA ARABICA L. TO LEUCOPTERA COFFEELLA (GUÉRIN-MÉNEVILLE)

SUSCEPTIBILITY OF 7 CULTIVARS OF COFFEA ARABICA L. TO LEUCOPTERA COFFEELLA (GUÉRIN-MÉNEVILLE

HOST INSTAR PREFERENCE OF MIRAX INSULARIS (MUESEBECK) (HYMENOPTERA: BRACONIDAE), A KOINOBIONT PARASITOID OF LEUCOPTERA COFFEELLA GUERIN-MÉNÉVILLE (LEPIDOPTERA: LYONETIIDAE)

HOST INSTAR PREFERENCE OF MIRAX INSULARIS (MUESEBECK) (HYMENOPTERA: BRACONIDAE), A KOINOBIONT PARASITOID OF LEUCOPTERA COFFEELLA GUERIN-MÉNÉVILLE (LEPIDOPTERA: LYONETIIDAE

Plant Allelochemicals and Insect Pathogens: The Effects of Alpha-Tomatine on the Susceptibility of Pseudoplusia Includens (Walker) and Heliothis Zea (Boddie) to the Entomogenous Fungus Nomuraea Rileyi (Farlow) Samson.

Research was conducted to determine the impact of the allelochemical, $\alpha$-tomatine, on the susceptibility of the lepidopterous pests, Heliothis zea (Boddie) and Pseudoplusia includens (Walker) to the entomogenous fungus, Nomuraea rileyi (Farlow) Samson. In one experiment, $\alpha$-tomatine inhibited colony formation and growth of N. rileyi, in vitro. In vivo, larval growth and developmental time of H. zea were affected by $\alpha$-tomatine and N. rileyi. The fungus was detected in the hemolymph and tissue of larvae treated with two concentrations (LC\sb{50} and LC\sb{90}) of N. rileyi conidia, including those fed $\alpha$-tomatine. At the LC\sb{50}, $\alpha$-tomatine protected larvae against N. rileyi and increased survivorship; at the LC\sb{90}, it inhibited the development of N. rileyi, thereby reducing production of conidia. In a second experiment, larval weight of P. includens was decreased by increasing concentrations (0.001 to 0.10% wet weight of diet (wwt)) $\alpha$-tomatine. A linear regression (Y = 217.86 $-$ 2,089.53 X, r\sp2 = 0.90) described the relationship between the larval growth of P. includens and the $\alpha$-tomatine concentrations. The effective dose required to reduce larval weight by 50% was calculated (ED\sb{50} = 0.048% wwt) and then validated in a subsequent experiment. In that study, a significant reduction (P $\leq$ 0.05) in mean body weight of 10- and 12-day-old larvae was obtained in larvae fed diet containing $\alpha$-tomatine when compared with larvae in the control. In a third experiment, N. rileyi was detected in the hemolymph and tissue of P. includens larvae treated with two concentrations (LC\sb{50} and LC\sb{90}) of conidia, including those fed $\alpha$-tomatine. At the LC\sb{90}, $\alpha$-tomatine protected larvae against N. rileyi and increased survivorship; at the LC\sb{50}, it inhibited the production of conidia of N. rileyi. Results from these experiments demonstrated that $\alpha$-tomatine exerted antagonistic effects against N. rileyi, and retained its antifungal qualities at the third trophic level, inhibiting the development of N. rileyi in P. includens and H. zea. In addition, these studies demonstrated that generalist insect-heribivores that tolerate $\alpha$-tomatine may be protected against entomopathogenic fungi

XYLOSANDRUS COMPACTUS (EICHOFF), COLEOPTERA: SCOLYTIDAE, THE BLACK TWIG BORER ATTACKING COFFEE IN PUERTO RICO

XYLOSANDRUS COMPACTUS (EICHOFF), COLEOPTERA: SCOLYTIDAE, THE BLACK TWIG BORER ATTACKING COFFEE IN PUERTO RIC

Una alternativa para limitar la población del minador del café: la aumentación de Mirax insularis

A biological control program for the suppression of the coffee leaf miner Leucoptera coffeella Guérin-Méneville, populations in Puerto Rico is promising. Such a project is favored because of stable habitat, host specificity of the pest, indirect pest and salubrious environment. Because of the negative ecological impact of chemical applications for controlling CLM populations, it is important to select an alternative to supress this pest in the shortest time possible. Classical biological control, new associations and other techniques such as augmentation are feasible approaches. Augmentation seems the most appropriate because it requires no time-consuming foreign exploration and quarantine procedures. Mirax insularis Muesebeck can be augmented in the field just before CLM population peaks by mass liberations of parasitoids reared in greenhouses. This approach is possible because the braconid is well adapted to Puerto Rican coffee plantations and the biology and phenology of the host is well known. To properly evaluate the impact of a biological control program, it is necessary to establish an economic threshold of the CLM damage.Un programa de control biológico del minador de la hoja del cafeto, Leucoptera coffeella Guérin-Méneville, en Puerto Rico parece ser prometedor. Dicho programa es factible porque las plantaciones de café proveen un ambiente estable, el minador es una plaga específica del café y que le ocasiona un daño indirecto. Debido al impacto ecológico ocasionado por las aplicaciones de insecticidas granulares para controlar el minador es necesario seleccionar la mejor técnica de control biológico, una que disminuya la población de la plaga en el menor tiempo posible para evitar la contaminación química. Varias técnicas de control biológico (control biológico clásico, nuevas asociaciones, incrementación) se evalúan desde el punto de vista teórico; todas parecen ser prometedoras. Sin embargo, la incrementación parece ser la más apropiada debido a su sencillez en comparación con otras técnicas que requieren complicados procedimientos tales como: exploración en el extranjero, cuarentena, etc. La incrementación de la población del parásito, Mirax insularis Muesebeck (Hymenoptera: Braconidae), en el campo, justo antes de que las poblaciones del minador aumenten, se puede realizar utilizando liberaciones masivas del parásito criado en invernaderos. Esta técnica es posible ya que el bracónido está bien adaptado en toda la región cafetalera de Puerto Rico. Además, se sabe la biología y fenología del minador del café y éste se puede criar usando técnicas de laboratorio. Es necesario, sin embargo, determinar el umbral económico del daño del minador de tal manera que se pueda evaluar apropiadamente el impacto de un programa de control biológico

PARASITOIDS OF PSEUDOPLUSIA INCLUDENS WALKER (LEPIDOPTERA: NOCTUIDAE) LARVAE ON THE SOUTH COAST OF PUERTO RICO

PARASITOIDS OF PSEUDOPLUSIA INCLUDENS WALKER (LEPIDOPTERA: NOCTUIDAE) LARVAE ON THE SOUTH COAST OF PUERTO RIC

MANGOES (MANGIFERA INDICA L.) SUSCEPTIBILITY TO AULACASPIS TUBERCULARIS NEWSTEAD (HOMOPTERA: DIASPIDIDAE) IN PUERTO RICO

MANGOES (MANGIFERA INDICA L.) SUSCEPTIBILITY TO AULACASPIS TUBERCULARIS NEWSTEAD (HOMOPTERA: DIASPIDIDAE) IN PUERTO RIC

EFFECTS OF CaC2 ON THE OVIPOSITION OF CARPOPHILUS HUMERALIS F. (COLEOPTERA: NITIDULIDAE)

EFFECTS OF CaC2 ON THE OVIPOSITION OF CARPOPHILUS HUMERALIS F. (COLEOPTERA: NITIDULIDAE

Dinâmica poblacional del parasitoide exôtico del minador del café, Mirax insularis Muesebeck en una plantaciôn de café al sol en Puerto Rico

A field study was conducted in a sunlight coffee grove of Puerto Rico to determine the population dynamics of Mirax insularis Muesebeck, the coffee leafminer [Leucoptera coffeella (Guérin-Méneville)] larvae parasitoid. Coffee leaf samples were collected monthly starting at early spring (March) and finishing in late autumn (December) of 2005. The highest parasitism ratio (0.2095) was recorded during August, followed by that of December with 0.1971. The lowest parasitization ratio (0.0120) was obtained in November. The average parasitism percentage obtained during the study was 20.13. Although the parasitism ratio was very low from April to July, in August when the coffee leafminer (CLM) population peaked, M. insularis also increased exponentially. However, from September to November a dramatic decrease in the parasitism ratio was observed. Heavy rains occurred during that season decreasing the CLM population and thus affecting the viability of suitable larvae for parasitization

PLATYPUS RATZEBURGI CHAPUIS (COLEOPTERA: PLATYPODIDAE): A NEW PEST ATTACKING COFFEE

PLATYPUS RATZEBURGI CHAPUIS (COLEOPTERA: PLATYPODIDAE): A NEW PEST ATTACKING COFFE