تعیین توزیع فضایی شپشک نخودی .Eulecanium Coryli L درختان هلو در مراغه

Peaches (Prunus Persica L.) belong to the Family Rosacea and the genus Prunus. Iran's distinctive climate and four seasons provide it with a strong to grow fruit trees. The peach tree produces fruit early and has a high economic output in a short time. The Lecanium scale Eulecanium Coryli L. is one of the important pests of peach trees. The Lecanium scale belongs to the family Coccidae and subfamily Lecaninae, which was first reported by Kothari in 1949 in Iran. The purpose of this research was to determine the spatial distribution of E. Coryli L. on peach trees in Maragheh orchards. The research was conducted during a crop season of 2022 in an orchard which was infected by the Lecanium scale . For sampling, the desired garden was visited for 28 days, and the number of scales on the trees was counted and recorded in the four geographical directions of north, south, east and west, and in three strata including the base, trunk and crown using a hand magnifier. 31 trees out of 1500 peach trees were were selected for sampling. Then, based on the results, the average number of scales counted for each of the directions and parts, variance, and standard error were calculated using SAS software. To determine the spatial distribution of this pest, K coefficient, Crowding index (David and Moore), Morisita index, Green index and b index in Taylor's law were used. The results of the present study showed that the results of different methods are almost similar and indicate the cumulative distribution pattern of the Lecanium scale. According to the studies of other researchers, cumulative distribution is the dominant pattern of distribution of insects in the nature. The results showed that the pattern of spatial distribution of scales was cumulative using any of the variance-to-mean ratio methods, Taylor regression method, and Morisita, Green, David, and Moore index in all three strata . While in the K coefficient, the spatial distribution in the northern part was cumulative and the rest of the strata were estimated as random. Studies utilizing this index have revealed the random spread of this pest. Using the Taylor's regression method, the distribution in the basic part was uniform and the other strata are estimated as cumulative. Also, the use of different statistical methods can provide more complete information about insect distribution patterns that can be used in the design of sampling programs and pest management. By utilizing the findings from this study and understanding the spatial distribution pattern, the density of this pest can be quickly estimated at a low cost by implementing suitable sampling programs. Additionally, these discoveries aid in making the best decisions for pest control in integrated pest management programs.