Occurrence and abundance of non-target arthropods in Bt and non-Bt lines of eggplant

Issue Date

10-2009

Abstract

The composition of above ground arthropod groups were monitored on Bt and non-Bt eggplant for 14 weeks from outplanting conducted in confined trial at Trangka, Bay, Laguna from December 2007 to April 2008. There were three replications each for Bt-positive and Bt-negative plots in BC3 F1 populations of Mara and DLP. Each replication had 210 plants of BC3F1 Mara X EE-1 and 189 plants of BC3F1 DLP X EE-1. Each replication occupied an area of approximately 150 sq meters. Direct count and sweep net were used in sampling. Common species were identified to species level while the less common ones to family or order. The relative diversities of arthropods were compared using rank-abundance tests and correlation in relative abundance for both types determined. Rarefaction analysis was done to tests and correlation in relative abundance for both types determined. Rarefaction analysis was done to test if diversity would be significantly different if sample sizes were equal. In general, temporal occurrence and population dynamics of the different tropic levels on Bt+ and Bt- plots did not show remarkable differences throughout the duration of the monitoring period. The population density oscillations of those in Bt+ and Bt- plots were congruent and followed the same pattern. Species evenness of chewing, predatory, and generalist predatory arthropods were found slightly higher in Bt- plots than in Bt+. However, in terms of relative species abundance, DLP Bt+ plots had greater abundance of sucking and herbivorous insects than BT-. The chewing arthropod community in Bt+ generally was dominated by a few species while the assemblage was more diverse in BT-. For herbivores it was the opposite with the Bt+ plots harboring a more diverse arthropod community as indicated by the overall higher species richness and evenness.

Source or Periodical Title

Philippine Entomologist

ISSN

0048-3753

Volume

23

Issue

2

Page

202-203

Document Type

Article

Frequency

semi-annually

Language

English

En – AGROVOC descriptors

ARTHROPODA; SOLANUM MELONGENA; EGGPLANTS; BACILLUS THURINGIENSIS; PEST MONITORING; POPULATION DENSITY

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