EFFECT OF SILICON, POTASSIUM AND CALCIUM COMPOUNDS ON GROWTH AND INCREASE THE EFFICIENCY OF CITRUS SEEDLINGS TO RESIST CITRUS LEAFMINER (Phyllocnistis citrella).

Abstract

Citrus leafminer is a serious pest of citrus, it cause an economic loses in nurseries and new plantings by decreasing growth rates. Therefore, a greenhouse experiment was carried out during 2014 and 2015 seasons in a private nursery at Kafr El-Sheikh Governorate, Egypt, to study the effect of silicon, potassium and calcium applications on growth and improvement the efficiency of Valencia orange seedlings to resist citrus leafminer. Nine treatments were arranged in randomized complete block design as soil and foliar applications of potassium silicate, silicon oxide, calcium and potassium nitrate beside control. The highest values of most growth measurements were recorded by potassium nitrate followed by potassium silicate as soil and foliar applications compared with the other treatments. All treatments enhanced leaf N, P, K and Si contents as compared to the control. Citrus leafminer infestation % and its severity were reduced with potassium silicate treatment which recorded the lowest values. The best anatomical structures of leaves were recorded with potassium silicate treatments compared to the control. In addition to, the positive effect on increasing the seedlings growth and reducing the percentage of leaves infestation, which help nursery men to get high net income due to sale more seedlings with higher price and preserve environment by reducing amount of insecticide used in controlling citrus leafminer.