Spatial distribution and evaluation sequential sampling model of the lesser moth (Batrachedra amydraula) on six traditional date palm fruit cultivars in Iran

Date Palm Lessr Moth Batrachedra amydraula Meyrick, is among the most important pests feeding on date fruits. Here, we studied the standardization of the class-specific sampling method to define the appropriate unit and number as well as to know population distribution pattern of B. amydraula in its specific ecological niches and fitting of continuous sampling model on six date palm cultivars in five provinces. Sampling was repeated in 10 days intervals from late March to early September. Distribution pattern of B. amydraula in the date palm orchards was calculated using indices of mean crowding, Taylor's law, mass average index, patchiness, and Iowa. The results showed that the mean density of B. amydraula varied from 3.304 (Sayer cultivar) to 0.804 (Rabi cultivar) in 20 studied fruits. According to Taylor's law, the distribution of this pest was cumulative. The sample size decreased by increasing density of B. amydraula in date palm orchards. The slope of decrement was different in the various date cultivars so that the lowest and highest number of the samples were observed in Sayer and Kabekab, respectively. By these results we can say that sequential sampling method can decrease sample size by 3 to 16 times compared with the classical sampling model.