Relating shading levels and distance from natural vegetation with hemipteran pests and predators occurrence on coffee
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Date
2015
Journal Title
Journal ISSN
Volume Title
Publisher
Journal of applied entomology
Abstract
The study was carried out to determine the effect of shading levels and/
or distance from the natural alpine vegetation (NAV) on the occurrence
of two insect functional groups: hemipteran herbivores and generalist
predators in farmers’ coffee fields in the Mt. Elgon region of Uganda.
Three distance categories from the NAV, that is (i) 0–250 m; (ii) 250–
1000 m and (iii) 1000–1500 m, were used to demarcate farms in the
first stage of selection, and within each distance category, three levels of
shading, that is (i) no shade, (ii) moderate shade and (iii) full shade,
were used for final selection of coffee farms for the study. A total of 90
individually owned coffee fields were studied; 30 for each distance category,
of which 10 represented each shading level. In two separate
rounds, inventories of scale insects (Coccus spp.), antestia bugs (Antestiopsis
spp.), root mealybugs (Planococcus spp.) and aphids (Toxoptera aurantii)
on coffee plants were made for the hemipteran herbivores, whereas ants
(Formicidae) and spiders (Araneae) were recorded for the predatory
taxa. The results showed that the interaction between distance from the
NAV and shading level consistently influenced the occurrence of the
insects in both functional groups. For scale insects, root mealybugs and
ants, it was closest to the NAV that shading-level effects were most discernible
and generally limiting. To the contrary, the occurrence of
aphids and spiders increased with the increase in the level of shading for
plants furthest from the NAV. These results indicate that if inclusion of
shade trees is to be a strategy in ecological pest management, the level
of shading should be determined basing on the insect taxa as well as
other pertinent factors in the landscape.
Description
Keywords
Ants, Aphids, Arabica coffee, Mealybugs, Scale insects, Spiders
Citation
Karungi, J., Nambi, N., Ijala, AR, Jonsson, M., Kyamanywa, S., & Ekbom, B. (2015). Relating shading levels and distance from natural vegetation with hemipteran pests and predators occurrence on coffee. Journal of applied entomology , 139 (9), 669-678. doi: 10.1111/jen.12203