Evaluation of processed kaolin clay (WP 95%) on reducing the population of olive psylla Euphyllura straminea Loginova. (Hem. Psyllidae)

Olive is one of the most important horticultural crops in Iran, especially in Guilan, Zanjan and Qazvin provinces. There are many pests in olive groves. Olive psylla, Euphyllura straminea Loginova. (Hem.: Psyllidae) is the most important insect pest of olive during flowering of trees in winter and the beginning of spring in Iran.
Material and In this research, the effect of kaolin powder (Sepidan®WP), on the developmental stages of the pest was evaluated in Guilan province during the growing season of 2012 and 2013. The treatments consisted of two kaolin concentrations of 3 and 5% and two treated with insecticide (diazinon EC 60% Volk oil 5%) and control (water spraying) which were compared using a layout of a randomized complete block design.
Results showed that in insect control treatments at 7, 14 and 21 days after spraying, diazinon insecticide, respectively, was 88.35, 80.43, 71.25%, kaolin 5% had 41.80, 35.22, 32.55% efficiency and kaolin 3%, 40.27, 25.12 and 16.12% respectively. On nymphs, the diazinon insecticide was 92.19, 89.25, 79.63, kaolin 5%, 61.06, 47.61, 42.43%, and kaolin 3%, 26.46, 31.10 and 22.61 % respectively. On the eggs, diazinon insecticide caused 31.16, 37.67, 47.17% efficiency, kaolin 5%, 28.07, 31.61, 36.61, efficiency, kaolin 3% 28.46, 25.18, and 26.32%, respectively. In the second year of the experiment, the results were the same as the first year.
According to the results, although the diazinon insecticide had the greatest effect on reducing the population of olive psylla, with regard to the necessity of reducing the application of chemical pesticides, Kaolin 5% treatment is recommended to be effective in reducing the number of nymphs, which is the main cause of damage