Effective Factors in Little Leaf Disease on Pistachio Trees

In this survey, effective factors in little leaf disease on trees were studied in different pistachio orchards in Kerman province. Little leaf disease is the most serious disease of pistachio in Iran. Affected trees reduced growth rates. The first symptoms of little leaf disease are those of nutrient deficiency: a slight yellowing and shortening of the needles and reducing of shoot growth. New needles are discolored and shorter than normal, and the tree loses all but the new needles near the tips of the branches. This study examined the causes of the disease through several researches conducted in various places (Anar, Rafsanjan, Shahrbabak, Noogh, Koshkoeih), in Kerman, south of IRAN. The following treatments were employed: 1- healthy leaflet from healthy tree, 2- healthy leaflet from problem tree, 3- problem leaflet from affected trees. Little leaf disease was divided into two groups (trees with severe and low problem). External leaflet, total leaf and leaf stalk analysis were performed to determine nutrient element content. The results showed that concentration of iron in leaf stalk healthy leaflet from problem tree were statistically significant because of fixed and decreasing mobility of iron. Reductions in iron, manganese, cooper and zinc were noticed in healthy leaflet from problem tree (healthy leaflet from healthy tree). In places where the soil is characterized by low and poor iron, manganese, cooper and zinc, alone or together, the disease appears in leaflets. Therefore any foliar application can tackle the problem for the following year.