Spatial dispersion and sequential sampling plan of the southern green stink bug (Hemiptera: Pentatomidae) on fresh market tomatoes
1989
Lye, B.H. | Story, R.N.
The spatial dispersion and sampling methodology of the southern green stink bug (SGSB), Nezara viridula (L.), were studied on fresh market tomatoes, Lycopersicum esculentum Mill. A visual count was used to sample SGSB populations from horizontal plant strata. More SGSB individuals were sampled from fruit clusters than from vegetative structures and samples from fruit clusters had the lowest coefficients of variation (CV) and the highest mean SGSB counts. Values of mean SGSB, CV, relative variation, and relative net precision indicated that the penultimate fruit cluster was the most efficient sampling unit among plant strata. Time consumed in counting SGSB on each stratum ranged from 3 to 10 s and showed little variation in mean or CV values. Regression equations estimating whole-plant populations of SGSB from individual fruit clusters were developed. The between-plant dispersion of SGSB fitted a negative binomial distribution with a moderate aggregation. A sequential sampling plan using the penultimate fruit cluster as a sample unit was developed to classify SGSB populations into light, moderate, and severe damage levels.
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