Management of Zonocerus variegatus with Pyrrolizidine Alkaloid Attracticide Bait

摘要

Background and Objective: Zonocerus variegatus is native to sub-Saharan Africa but assumed pest status following the accidental introduction of the exotic Siam weed, Chromolaena odorata . Both the insect and the weed cause economic damage in agriculture, forestry and conservation. Zonocerus. variegatus is strongly attracted to the flowers of C. odorata from which the insect sequesters pyrrolizidine alkaloids (PAs) for protection against its natural enemies and diapausing eggs. The present study aimed to reduce field populations of Zonocerus variegatus below economic injury level using a pyrrolizidine alkaloid attracticide bait. Materials and Methods: Field trials were conducted to determine efficacy of a novel PA based attracticide bait developed for the field management of Z. variegatus in open fields at the Forest Savannah Transition and Semi-deciduous ecological zones of Ghana. Part of the study also investigated the attraction of Z. variegatus to various parts of the developed PA based attracticide bait in an open field and a citrus nursery in a Randomized Complete Block design. Results: Most hoppers were attracted to the inside of the PA based bait where the attracticide was placed. The results on the field efficacy trials showed an efficiency of about 0.3% knock down per trap of field population of Z. variegatus . The 3rd to 5th instar larvae of Z. variegatus persist in the field for about 100 days; a period when the PA based attracticide bait will be most effective in reducing populations of the insects. Conclusion: This study therefore concludes that the PA based attracticide bait will reduce dry season populations of Z. variegatus as well as in surveillance studies.