Researcher Embrapa Santo Antonio de Goias, Goias, Brazil
The rice stink bugs Oebalus poecilus and O. ypsilongriseus are important pests that feed on rice panicles in all Brazilian producing areas. A more time-efficient method of detecting and quantifying their population is important for the development of an integrated strategy of control accepted by the growers. Fifteen commercial rice fields were sampled, at least once, during panicle development stages to collect information to describe the spatial distribution of the stink bug and to determine the parameters for establishing sampling plans and improve strategy of control. A total of 2,250 locations were sampled. A sample unit consisted of 10 consecutive sweeps across a 180o arc with a
sweep made on each forward step. Sampling was conducted in a regular and uniform grid to guarantee coverage of the field. Presence of macroscale variation indicated that stink bug populations can be highest in parts of the field with presence of weeds (Echinocloa spp. and Paspalum spp). The probability distribution that better adjusted to the stink bug population was negative binomial. Because spatial correlation was little significant, sampling procedure can follow any field direction that result in the least physical effort. Samples may be taken either circling the perimeter of the fields, following a zigzag pattern, or field transcept. The spatial dependence was up to 65 meters, which is the shortest distance between successive samples in field sampling procedures.
