Environmental Entomology (1995) 24, 1487-1494

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Patricia J. Folgarait, Robert J. Marquis, Par Ingvarsson, H. Elizabeth Braker and Marcela Arguedas (1995)
Patterns of attack by insect herbivores and a fungus on saplings in a tropical tree plantation
Environmental Entomology 24 (6), 1487-1494
Abstract: We investigated the effects of plant density, plant diversity, and light availability on susceptibility of saplings of Stryphnodendron microstachyum Poeppig and Endlicher to attack by herbivores and pathogens in the lowlands of northeastern Costa Rica. Seedlings of S. microstachyum were planted at either low or high density. High density stands were planted in 2 environments with 2 plant diversities within each environment: monocultures in abandoned pastures (=sun) and in 5-yr-old secondary forest (=shade), or polycultures in which S. microstachyum was planted with 4 other species also in sun and shade. Low density stands consisted of isolated individuals in 4 types of sites (abandoned pasture, secondary forest understory, primary forest understory, and primary forest light gap). Numbers of galls (Diptera: Cecidomyiidae), larvae (Lepidoptera: Noctuidae: Euclystis), and fungal spots (Melanconiales: Pestalotia) were greater in the high density stand than in low density stands, and greater in the shade than in sun. We found no differences in infection between monocultures and polycultures at high density, nor did we find Euclystis larvae or Cecidomyiidae galls in low density stands. Numbers of fungal spots per leaf and density of galls were greater on larger plants. These data suggest that higher plant densities increase the probability of attack by herbivorous insects and leaf pathogens, and that plantations of tropical native tree species in partial shade, as a means of reforestation, run the risk of outbreaks of normally rare plant enemies. Furthermore, the observed positive relation between plant size and attack suggests that plantations of this tree species will become more susceptible to pest outbreaks as the trees mature.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Database assignments for author(s): Patricia J. Folgarait

Research topic(s) for pests/diseases/weeds:
environment - cropping system/rotation

Pest and/or beneficial records:

Beneficial Pest/Disease/Weed Crop/Product Country Quarant.

Euclystis (genus) Stryphnodendron (crop) Costa Rica