Standardized sampling plan for Jasmine whitefly Aleuroclava jasmini (Takahashi) (Hemi.: Aleyrodidae) in Khuzestan citrus orchards, Southwest of Iran

Spatial distribution, precision levels, number of samples for Jasmine whitefly, Aleuroclava jasmini (Takahashi) (Hemi.: Aleyrodidae) was studied during 2010 and 2011 growing seasons in citrus orchards of Khuzestan Province, Iran. To do this, the samples were taken from 41 citrus orchards, in four geographical directions and four sides of a tree (five leaves on each sides of a tree) with stratified random sampling method. Number of eggs, 1st-4th instar nymphs and exuviae per 1 cm2 on lower surface of mature leaves were counted. Results showed that maximum of mean density of eggs and pupae in each citrus orchards was 34.9/cm2 and 49.13/cm2 on each leaf, respectively. There was no significant differences between the relative variation at each developmental stages at two spring and autumn generations, geographic directions of trees in citrus orchard and different geographical sides of each tree. The data of spatial distribution for the pest population among all citrus orchards with both Iwao’s Patchiness regression method and Taylor’s Power Law indicated that Taylor\'s Power Low showed a better fit than Iwao\'s model. The regression coefficient (b) for eggs, pupae and exuviae were 1.82, 1.67 and 1.79, respectively showing negative binomial distribution among populations. The common K for egg, pupae and exuviae, sum of alive stages and total population were determined 0.29, 0.57, 0.36, 0.7 and 0.79, respectively. The lowest level of permissible precision was determined 12.5% for this pest. Number of fixed samples in the precision level of 0.25 for egg, pupae, exuviae, sum of alive stages and total population were calculated 55, 28, 45, 23 and 20 leaves, respectively.