JWSS - Journal of Water and Soil Science

High attraction is reported for yellow sticky traps to capture pistachio psylla. In pest management, it is important to forecast from the adult population density the density of other developmental stages in order to gain an estimate of the density in damaging stages. In 1998 and 1999, yellow sticky boards with 10150.15 cm were installed in two pistachio orchards in Borkhar district of Isfahan and egg and nymphal densities were simultaneously counted on leaves. Collected data were used to determine regression relationships between two weeks’ average egg density, first and second nymphal instar densities and the sum of egg and first and second instar nymphal densities, one week after the average adult capture in two previous weeks. A low correlation was found between egg count and adult capture, but higher coefficients were obtained between other stages. It was possible to estimate first and second instar nymphal populations from the following equations:

 For high adult densities (X):

Y= 58.6+0.4762X-(7*10^-5)X²                                    R²=0.82                             commercial orchard

 Y= 27.68+0.5092X-(5*10^-5)X²                       R²=0.86                              abandoned orchard

and for low adult densities (X)

Y= 1.7162X-17.454                                     R²=0.97                              commercial orchard

 Y= 1.1117X-4.9841                                    R2=0.90                              abandoned orchard

The application of this method is recommended for the management of pistachio psylla.