Date of Award

2011

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Natural Resources

First Advisor

Jackai, Louis E.N. Dr.

Abstract

A laboratory study was conducted to compare food utilization and suitability of Nezara viridula on selected varieties of tomato and cowpea. A two-year field study was performed to evaluate the effectiveness of biorational pesticides (Agroneem®) and conventional pesticides (Imidacloprid or Thiamethoxam) to suppress and enhance the population of insect pests and beneficial, respectively, on both crops. In the first year both pesticide groups were applied following manufacturer’s recommendation (10-14 d cycles), and in the second year the application of the pesticides was driven by monitored thresholds of insect pests. In the laboratory study conducted on the feeding behavior, nymphs performed better on cowpea than on tomato. Although the nymphs required comparable duration to complete development, and attained similar weights at adult emergence, mortality was higher on the seeds of Pinkeye purple hull (PPH) than those of Mississippi Silver (MS). Mortality on both varieties of tomato was comparable. Consumption index and growth rate were higher on cowpea than tomato which indicates cowpea as a preferred host. In the field study the most predominant species of insects recorded on both crops were in the families: Chrysomelidae, Pentatomidae, Cicadellidae, Vespidae, Sarcophagidae, Thripidae and Sphingidae. In both years the number of insects on cowpea was higher than on tomato. The number of insects on these crops was higher in the second year compared to the first. However, there was no significant difference (P>0.05) in pest number between varieties in the treated plots. The yield of cowpea and tomato was comparable in all sprayed plots.

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