A comparative study of two sampling approaches for the coconut whitefly and its associated parasitoids in Inhambane province, Mozambique

Research to develop and evaluate pest management tactics requires meaningful measurements of populations of pests and/or beneficial organisms for accurate and precise estimation. Sample size and number of samples corresponding to fixed levels of precision varies with the population levels of interest. This means that a fixed sample size that provides adequately precise population estimates at low population level is unnecessarily large when the population levels are high. A study was conducted to compare two sampling approaches for coconut whitefly, Aleurotrachelus atratus (whitefly density) and the associated parasitoids (density and rate of parasitism) in Inhamabane Province, Mozambique in order to guide future research in relation to field sampling approaches especially where resource constraints are important considerations. Two approaches were compared to assess their similarities and differences in terms of results based on whiteflies and their associated parasitoids in Inhambane province. Results from five districts of the province showed that whitefly density differed significantly between the two approaches/ methods according to t-test at 95% confidence level (P = 0.0000). However, there was no significant difference between the two methods in terms of parasitoid density at 95% confidence level (P = 0.0635). Nonetheless, studies for comparison of insect sampling methods should include reduction of distance between sampling points and increasing the number of plants per sample (sample size) to increase precision.