Predation and Food as Factors Affecting Survival of Nezara viridula (L.) (Hemiptera: Pentatomidae) in a Soybean Ecosystem

Abstract

Direct field observations and use of radioactive phosphorus (32P) as a tracer showed 18 insect and 6 spider species, representing 6 orders and 19 families, to be predators of Nezara viridula (L.) in a soybean ecosystem in Louisiana. Solenopsis invicta Buren was the dominant egg predator during the vegetative stages of soybean development, while cannibalism of eggs by adults and nymphs of N. viridula was also frequently observed during this stage. Grasshoppers were the more important egg feeders during the reproductive stages of plant development. Life tables developed for N. viridula in field cages showed that survival to adult was 0.5% during the vegetative and flowering stages and 4.5% during pod set, but it increased significantly to 38.2% when seeds were formed. Under field conditions during the latter period, survival to fourth-instar nymphs declined to 8.7%, from which it was concluded that, in this particular ecosystem, 33.6% mortality was caused by predation and 57.7% was due to other factors.