Some parasites of Segestes decoratus Redtenbacher (Orthoptera: Tettigoniidae) and their possible use in the biological control of tettigoniid pests of coconuts in papua new guinea

Abstract

AbstractA number of tettigoniids belonging to the genera Sexava, Segestes and Segestidea are responsible for severe defoliation of coconut palm, oil palm and Pandanus spp. in Papua New Guinea. Most chemical and cultural methods of control are either impractical or uneconomic. The possibility of biological control was examined with reference to some of the natural enemies of Segestes decoratus Redtenbacher, in particular a parasite of nymphs and adults, Stichotrema dallatorreanum Hofeneder, as well as the egg parasites Triteleia atrella (Dodd), a species of Tetrastichus near T. dubius (Waterston) and a second species of Tetrastichus. It was concluded that S. dallatorreanum contributed to the control of Segestes decoratus in areas with an evenly distributed rainfall and that the parasite had potential as a biological control agent in areas where it is not endemic against pest species of Sexava, Segestes and Segestidea. A survey of the egg parasites showed that they were not effective in controlling the pests as they were only able to parasitize eggs in exposed oviposition sites. Egg predators of unknown identity were responsible for higher egg mortality than were the egg parasites.