Title page for ETD etd-05022009-040744


Type of Document Master's Thesis
Author Ludwig, Scott W.
URN etd-05022009-040744
Title Role of trap crops on harlequin bug, Murgantia histrionica (Hahn), population dynamics and parasitism in broccoli plots
Degree Master of Science
Department Entomology
Advisory Committee
Advisor Name Title
Kok, Loke T. Committee Chair
Pfeiffer, Douglas G. Committee Member
Pienkowski, Robert L. Committee Member
Keywords
  • Harlequin bug
  • Broccoli
  • Trap crops
Date of Defense 1995-12-05
Availability restricted
Abstract

Trap crops were evaluated for harlequin bug control in broccoli field plots in 1994 and 1995. Mustard and rape prevented low densities of harlequin bug from reaching broccoli, but at high densities the insect moved from the trap plants into the broccoli. This indicates that harlequin bugs that are attracted to trap plants may damage the protected broccoli if their numbers are not prevented from increasing.

Harlequin bugs were shown to have two and a partial third generation a year. Trissolcus murgantiae Ashmead and Ooencyrtus johnsoni Howard, were identified as egg parasitoids. Their combined parasitization levels for the two years were 8% and 37%. T. murgantiae accounted for 87% and 96% of the parasitization, respectively..

When 19.6 cm and 11.9 cm broccoli plants were exposed to five densities of harlequin bug adults a negative correlation between plant mortality and insect density was observed (y = 38.00 - 2.32x, r2 = 0.95 and y = 22.17 - 1.17x, r2 = 0.99, respectively). No correlation was observed in broccoli plants 11.9 tall..

Host plants affected harlequin bug development. Nymphs developed faster when reared on rape in comparison with mustard. The preoviposition time for rape reared nymphs was shorter than mustard reared insects. Fecundity and viability of eggs were not different for harlequin bugs reared at different sex ratios.

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