Influence of moisture content of leaf on population fluctuations of common pistachio psylla, Agonoscena pistaciae, (Hemiptera: Aphalaridae), in central Iran

پذیرفته شده برای پوستر

عنوان دوره: سومین کنگره بین المللی حشره شناسی ایران

¹Department of Plant Protection, Faculty of Agriculture, University of Tabriz, Tabriz, Iran

²Department of Plant Protection, Pistachio Research Institute, AREEO, Rafsanjan, Iran

Pistacia vera L. (Sapindales: Anacardiaceae) is a very important horticultural product in Iran. Common pistachio psyllid (CPP) Agonoscena pistaciae Burckhardt and Lauterer (Hemiptera: Aphalaridae), is a key pest of pistachio. This study was conducted to determine the effect leaf moisture content on CPP population fluctuations in 2016 and 2017. We monitored the abundance of pistachio psylla in four pistachio orchards (area no less than 0.5 ha) on 24 trees located in Maybod County, Yazd province in the center of Iran. Half of the trees were in Off year and the other half in ON year. Locations of the orchards extended over a distance of 2.6 km. The coordinates of the sites were: 1) 32°16´4˝N, 53°58´50˝E, 2) 32°16´9˝N, 53°58´54˝E, 3) 32°16´54˝N, 53°59´8˝E and 4) 32°17´23˝N, 53°59´24˝E. In order to reduce the effect of the root stock and scion, Badami cultivars (commercial non grafted ones) were used. The moisture content of pistachio leaves was measured by weighing leaves once immediately after picking up and once again after drying them in an Owen for 7 days. Sampling was done by removing healthy mature leaves from the middle of infertile branches at a height of 2 m. From each tree, 20 leaves were collected. Number of egg and nymph were measured by Southwood & Jepson’s (SJ) graphical method, simply by dividing the area under the SJ curves into developmental time and then subjecting the result to one-way ANOVA using SPSS. Degree-days rather than chronological time were used both for drawing the SJ’s graphs and developmental times. One-way ANOVA was used to test if egg and nymph numbers and moisture content of pistachio leaf were similar in all orchards. To determine the relationship between CPP population growth and leaf moisture content, we used regression and STATISTICA software. The results revealed a significant difference between the moisture content of the leaves of the four locations (F=9.27; df=3, 20; P-value<0.001) ranged between 48.9–55.5%. But there was no significant difference in the abundance of eggs and nymphs at different locations (F=0.99; df=3, 20; P-value=0.418 for eggs; F=2.6; df=3, 20; P-value=0.08 for nymphs). The regression analysis between moisture content of leaf and number of egg and nymph showed no significant relationship between them (df=1, 22; adjusted R2=0.045; P-value=0.947 for egg; df=1,22; adjusted R2=0.025; P-value=0.515). It seems that in contrast to many other herbivore insects, moisture content of leaf has no considerable effect on CPP abundance in natural range of moisture variations.

pistachio psyllid؛ Leaf moisture of؛ population fluctuations