shade tree tonka (dipteryx odorata) new host for pratylenchus loosi in tea plantation

the root lesion nematode tea,pratylenchus loosi, is currently the most important damage-causing factor of tea in iran and all over the world. this nematode is considered as the most damage-causing factor of tea in many tea-producing countries including sri lanka, china, india, japan and bngladesh. in recent years, it’s also considered as a key disease and damage-causing of tea that cause to severe damage to tea shrubs, so that the growth of infected plants has been decreased and because of inability in creating the new branches and leaves, yield loss is severe. tea plant is the host of this nematode and in addition to tea, it has been reported in the weed of forest millet, citrus and cherry in iran, while citrus, apple, pear, grass and several species of weed are considered as its host in the world. this nematode has been reported from strawberry in sri lanka and this plant has been introduced as weak host. in order to investigation of host range of this nematode, a study is conducted in iranian tea research institute in 2013. tree tonka (dipteryx odorata), has been imported as shade tree and cultivated in tea farm margins in some areas. in second half of 2013, symptoms of nematode infection on shade trees were observed in shahid-eslami tea farm placed in iranian tea research institute. after sampling the soil and root of this tree, extraction of nematodes from root was done using conventional methods. after investigation of morphological and morphometric characters using scientific authorized references, isolated nematode species from root was diagnosed as pratylenchus loosi. loof, 1960.the mentioned nematode population was counted in average of one hundred grams of soil as 30 nematodes and in 30 grams of root as 210 nematodes in february 2014. it is the first report of tonka plant as a host (d. odorata) to p. loosi in the world. considering the permanent tonka tree, its role is crucial in survival of root lesion nematode p.loosi in tea farms.