تاثیر خسارت کنه قرمز مرکبات Panonychus citri (McGregor 1916) روی غلظت کلروفیل برگ مرکبات

The citrus red mite (CRM) Panonychus citri (McGregor 1916) is one of the most important citrus pests in northern Iran. This study was conducted to study the effect of CRM on Chlorophyll concentrations of Citrus sinensis cv. Thomson navel orange during in the Horticultural Research Station located at Ghaemshahr County, (Mazandaran Province, north of Iran) during the growing seasons of 2016. The experiment was based on a randomized complete block design on the same age trees of Thomson Novel oranges with 1 control treatment (without CRM control) and 4 treatments for artificial pollution with CRM (weekly and one treatment per week) in 4 repetitions. The results of the analysis of the experiment showed that the level of chlorophyll content measured in treatments was significant at 1% level (p <0.001). A comparison of the means of chlorophyll concentration in treatments by Turkey’s method at the 5% level showed that the treatments were significantly different and were classified into different groups. The results showed that the highest average leaf chlorophyll concentration (79.13 ± 1.06) was related to the control treatment with mean density of 0.05 ± 0.08, different stages of age of CRM in per leaf and in group a, but the lowest chlorophyll concentration of leaf was related to treatment 4 with a mean density of 10.59 ± 0.91 different stages of age in per leaf and with mean chlorophyll content of leaf 62.08 ± 1.50, and placed in group c. Also, the results of correlation calculations between mean population density and chlorophyll concentration showed a strong and significant negative correlation (r = -0.911, p = 0.031). Therefore, with the increase in the population of CRM, the chlorophyll concentration of the leaf decreases and eventually causes the leaves to be dried and thrown in Thomson navel oranges.