Effects of Blackbirds (Agelaius phoenicius) on Stink Bug (Hemiptera: Pentatomidae) Populations, Damage, and Yield in Florida Rice

Abstract

Blackbirds are important agricultural pests that can cause major economic losses in a variety of crops. Although birds in other agro-ecosystems may perform biological control services by controlling insect pests, the potential of blackbirds to provide these services in rice had not been evaluated. We used bird exclosures to evaluate the effects of blackbirds on stink bugs in rice and on crop damage and yields in the Everglades Agricultural Area in southern Florida. Experiments were conducted in both the main rice crop and the ratoon crop. We found no difference in the abundance of rice stink bugs (Oebalus spp.) in exclosures vs. controls, indicating that predation by birds did not reduce stink bug populations. Damage to rice by stink bugs (pecky rice) was similar between exclosures and controls, as well. However, bird damage, quantified as the percentage of panicles damaged, differed by as much as an order of magnitude in exclosures vs. controls. Mean damage estimates were 3.5% in the bird exclosures vs. 35.3% in the control for the main crop and 4.5% and 20.5%, respectively, in the exclosures and controls for the ratoon crop. Nonetheless, mean yields did not differ between exclosures and controls. Our results suggest that despite their conspicuous presence, blackbirds have little effect on stink bug populations or rice yield in Florida rice fields.