EFFECTIVE CONTROL OF CITRUS NEMATODE (Tylenchulus semipenetrans) BY INDIVIDUAL CANOPY SOIL SOLARIZATION OF INFECTED SWEET ORANGE TREES *

Citrus nematode (Tylenchulus semipenetrans) is a serious pest of citrus trees in north and south of Iran. During 2010-2012, the effect of soil solarization on canopy soil of individual infected sweet orange trees evaluated in a randomized complete block experiment, in Darab region, Fars province. Trees were treated at the beginning of the nematode activity in spring for two periods, 45 and 60 days and at the onset of maximum temperature in June 21 for a period of 60 days. Non-solarized plots were used as control. Recorded data showed that the maximum mean of monthly temperature reached 39.7- 41.8 °C, under plastic covering, at soil depth of 15cm. The results indicated that the percentage of the nematode survival reached to zero or near zero in all treatments. There were no increases in the citrus nematode populations three months and one year after solarization (P≤0.05). The population densities of some plant ectoparasitic nematodes belong to other families and also rhabditids were less affected by the treatments. Due to severe reduction of citrus nematode population density, the vegetative, as well as the reproductive factors of the treated trees were enhanced in the consequent year (P≤0.05). After soil solarization, the mean yields in different treatments were increased 71.6-77.9 and 70.2-77.8% in comparison to the initial measurement and control٫ respectively.