بررسي مقاومت درختان اراضي شني خوزستان به موريانه

A study of wood resistance of four tree species to sand termite Psammotermes hybostoma Desneux in sand dunes of Khuzestan province

The sand dunes of Khuzestan, with an area of 350000 hectares, includes 5.3 percent of the whole province. Since 1995-1999, annually on average, for the biological stability of the sand dunes, 1160 and 1632 hectares have undergone mulching and plantation respectively. Despite of protecting economical sources of the province, this process has tremendous effects from the environmental point of view. Tamarix aphylla,Ziziphus spine Christi, Eucalyptus camaldulensis 9616 and Prosopis juliflora are the four most important plant species which are planted for stabilization of sand particles. One of the most important pests, which damages these plants and may demolish them, is the sand termite or Psammotermes hybostoma. Selecting resistant plants to this termite species would reduce the sand stabilization costs on these lands. For the purpose of selecting resistant species among the ones available, 64 blocks of wood with the dimensions of 10.5x4.5x5 cm. From each 13 years old undamaged trunk of the four species were used. The blocks were buried in sand in the depth of 30cm. for 3 summer months. Meanwhile, the physical and chemical analysis of the wood of the Plant species was specified. Results showed that 72.5, 47.5, 25 and 15 percents of the wooden blocks belong to T. aphylla, Z. spine Christi, E. camaldulensis 9616 and P. juliflora were respectively infected with the termite. The feeding indices (reduction of wood due to termite feeding + reduction of wood due to evaporation) were 27.3, 18, 10.5 and 3.9 percent for T. aphylla, Z. spine Christi, E. camaldulensis 9616, and P. juliflora respectively. The actual feeding of termite from 1000 grams blocks of each plant species were 6.2,4.2, 1.6 and 1.3 percentively. These experiments showed that the tree species P. juliflora was the most resistant among the four plant species.