Factors influencing the abundance of pests in production fields and rates of interception of Dracaena marginata imported from Costa Rica

Importation of live nursery plants, like Dracaena marginata Lamoureux (Ruscaceae), can provide a significant pathway for the entry of foliar pests from overseas into the United States. We studied the abundance of foliar pests of quarantine importance found on Costa Rican-grown D. marginata. These include five genera of leafhoppers (Heteroptera: Cicadellidae, Oncometopia, Caldweliola, Diestostema, Gypona, and Empoasca), Florida red scale (Heteroptera: Disapididae, Chrysomphalus aoinidum (L.)), katydids (Orthoptera: Tettigoniidae), and a snail (Succinea costarricana von Martens (Gastropoda, Stylommatophora, Succineidae)). In our first study, we examined the rationale behind size restrictions on Dracaena cuttings imported into the United States from Costa Rica. When comparing plant size, no differences were found in the abundance of quarantined pests on small (15–46 cm), medium (46–81 cm), and large (81–152 cm) propagules. In a second study, we estimated monthly abundances of pests in production plots for 1 yr to determine their relationship to rates of interception at U.S. ports. In any given month, <6% of the marketable shoots standing in the field were infested with at least one quarantine pest. There was no relationship between the average monthly frequencies of pest detection in the field and in U.S. inspection ports. Pest detections increased during the 1 mo when average monthly shipments were abnormally high. Our data suggest that off-shore postprocessing efforts to remove pestinfested material from the market stream need to be adjusted to accommodate sharp increases in the volume of shipped plants.publishedVersionFil: Hidalgo, Eduardo. Centro Agronómico Tropical de Investigación y Enseñanza (CATIE); Costa Rica.Fil: Benjamin, Tamara. Purdue University. College of Agriculture. Department of Entomology; United States.Fil: Casanoves, Fernando. Centro Agronómico Tropical de Investigación y Enseñanza (CATIE); Costa Rica.Fil: Sadof, Clifford. Purdue University. College of Agriculture. Department of Entomology; United States

Influence of silvopastoral systems on the distribution of ticks in livestock farms in tropical dry forest

P?ginas 38-40.La corta de ?rboles en pasturas ha sido implementada en algunas regiones como una medida de control sanitario, ya que muchos productores creen dicen que los ectopar?sitos han sido encontrados bajo los ?rboles. El objetivo de este estudio fue generar informaci?n sobre la distribuci?n de garrapatas en el suelo de fincas ganaderas en el tr?pico seco. Este estudio fue realizado en cuatro fincas ganaderas de la provincia de Guanacaste, Costa Rica. La influencia de la cobertura de ?rboles individuales, en grupos, en cercas vivas y pasturas abiertas establecidas en pasturas de Brachiaria brizantha y Hyparrhenia rufa fueron evaluados. No se encontraron diferencias significativas (p = 0,77) en el n?mero de sitios con larvas de garrapatas larvas o en el total de n?mero de larvas en el suelo (p = 0,18) entre sistemas silvopastoriles y pasturas abiertas. Se encontr? una relaci?n significativa entre el n?mero total de larvas en el suelo y la presencia de ?rboles dispersos en la pastura (p=0,002), la humedad relativa (p=0,004) y la temperatura del aire (p=0,005). Se encontr? una relaci?n negativa entre el n?mero de sitios con larvas de garrapatas en el suelo y el ?rea de cobertura de dosel (p = 0,03). No se encontraron diferencias significativas entre la poblaci?n de larvas en el suelo bajo la cobertura de dosel entre sistemas silvopastoriles y pasturas abiertas, a pesar de encontrarse diferencias microclim?ticas (temperatura del aire y humedad relativa) entre estos sitios.ABSTRACT. The elimination of trees in pastures has been implemented in some regions as a control measurement due to lives-tock farmers think ectoparasites are found under tree canopy. The objective of the study was to generate information regarding the influence of tree cover in silvopastoral systems on tick distribution in soil of livestock (cattle) farms in the dry tropics. The influence of individual trees and trees in groups and live fences and open Brachiaria brizantha y Hyparrhenia rufa pastures was evaluated. No statistical differences (p=0.77) in the number of sites with tick larvae of or in the total number of larvae in soil (p = 0.18) between silvopastoral systems and open pastures. A significant relationship between the total number of tick larvae in the soil and presence of individual trees in pastures (p = 0.002), the relative humidity (p=0.004) and air?s temperature (p=0.005). A negative relationship was found between the number of sites with tick larvae in the soil and canopy tree area. No significant differences in larvae population in soil under tree cover between silvopastoral systems and open pastures, despite microclimatic conditions (air?s temperature and relative humidity) between both sites

An assessment of silvopastoral systems condition and their capacity to generate ecosystem services in the Colombian Amazon

Livestock production in the Colombian Amazonia is typically dual-purpose (meat and milk) based on silvopastoral systems. We aimed to assess how the ecological condition of these systems correspond to the ecosystem services they generate based on an assessment of farmers’ knowl-edge of the tree species. We evaluated 159 paddocks. We recorded 143 tree species from 37 families, with 22 species being most common (relative occurrence frequency = 57%). Based on tree species composition, we characterized four states of silvopastoral condition (hereon ‘pad-dock condition types’) using clustering techniques: (i) High structural complexity and highest tree species richness (HSCR); (ii) High species diversity and tall trees (HDTT); (iii) High species diversity and medium-sized trees (HDMT); (iv) Structurally simple with lowest species richness (SSLR). Tree species richness was significantly higher in HSCR (11.70 ± 1.47 per paddock), than in SSLR (2.86 ± 0.80). HDTT and HDMT had similar richness, with intermediate values (5.55 ± 0.82 and 6.38 ± 0.51, respectively). Farmers appreciate a number of ecosystem services provided by the silvopastoral system, but a limited number of tree species are valued. This indicates the need for additional biodiversity conservation measures in these landscapes, including measures to improve knowl-edge about the value of tree species with few occurrences or low densities. Tree species richness; silvopastoral system condition; biodiversity conservation; Importance Value Index; Index of Cultural Importance; tree selective preservationpublishedVersio

Dung Beetle Assemblages Attracted to Cow and Horse Dung: The Importance of Mouthpart Traits, Body Size, and Nesting Behavior in the Community Assembly Process

Dung beetles use excrement for feeding and reproductive purposes. Although they use a range of dung types, there have been several reports of dung beetles showing a preference for certain feces. However, exactly what determines dung preference in dung beetles remains controversial. In the present study, we investigated differences in dung beetle communities attracted to horse or cow dung from a functional diversity standpoint. Specifically, by examining 18 functional traits, we sought to understand if the dung beetle assembly process is mediated by particular traits in different dung types. Species specific dung preferences were recorded for eight species, two of which prefer horse dung and six of which prefer cow dung. Significant differences were found between the functional traits of the mouthparts of the dung beetles attracted to horse dung and those that were attracted to cow dung. Specifically, zygum development and the percentage of the molar area and the conjunctive area differed between horse and cow dung colonizing beetles. We propose that the quantitative differences in the mouthpart traits of the species attracted to horse and cow dung respectively could be related to the differential capacity of the beetles to filtrate and concentrate small particles from the dung. Hence, the dung preference of dung beetles could be related to their ability to exploit a specific dung type, which varies according to their mouthpart traits. Moreover, we found that larger and nester beetles preferred cow dung, whereas smaller and non-nester beetles preferred horse dung. This finding could be related to the tradeoff between fitness and parental investments, and to the suitability of the trophic resource according to the season and species phenology

How climate awareness influences farmers’ adaptation decisions in Central America?

Central America is one of the regions with the highest vulnerability to climate change, with negative effects projected to affect its economy and food security. To address this issue, an integrative farm management approach such as Climate-Smart Agriculture can help reorient agricultural practices towards climate adaptation and food security. Past studies have shown that several factors can either hinder or encourage the adoptions of Climate-Smart practices, including subjective expectations and perceptions. Building on this literature, we analyze farmers' climate awareness and their perceptions regarding the change in climate patterns as well as their choices of farming practices to adapt to these changes. We show that reforestation was the preferred adaptation strategy among interviewed farmers and that educational profiles and the size of landholdings drive the adoption of this and other practices. Soil management and introduction of new crops are preferred by literate farms with large farmlands, whereas illiterate farmers with smaller farmland tend to move towards farm intensification with an increase in the utilization of external inputs. Our findings provide evidence to support the design of capacity development interventions targeting specific groups of farmers according to their main crop and education profile.How climate awareness influences farmers’ adaptation decisions in Central America?acceptedVersio