Temporal Fluctuations in the Population of Citrus Nematode (Tylenchulus semipenetrans) in the Pothowar Region of Pakistan
Temporal Fluctuations in the Population of Citrus Nematode (Tylenchulus semipenetrans) in the Pothowar Region of Pakistan
Muhammad Saeed1,2,*, Tariq Mukhtar1 and Malik Abdul Rehman3
ABSTRACT
The study of the population dynamics of citrus nematode (Tylenchulus semipenetrans) in a production area is required for the assessment of damaging potential of the nematode to citrus, identification of key factors that influence population densities, and to devise effective management strategies. In the present study, seasonal fluctuations in the population densities of T. semipenetrans were studied in two citrus orchards naturally infested with citrus nematode during the year 2014. The effect of soil temperature was also evaluated on the populations of the nematode. The nematode populations differed significantly at both the soil depths. The populations were significantly higher at a depth of 30 cm as compared to 45 cm throughout the year at both the orchards. Similarly, females per gram of roots also followed the same pattern. The number of nematodes in the soil and females in the roots were the higher during the months of April to June and August-September showing two peaks throughout the year. The regression analysis between temperature and number of nematodes in the soil and females in the roots showed highly significant results at both the orchards. A direct relationship was observed between nematode population and temperature. Maximum nematode and female populations were observed at a temperature ranging between 26°C to 29°C at a soil depth of 30 cm. On the other hand, minimum populations were recorded at a temperature range of 9°C to 12°C. Similar trends were observed at the soil depth of 45 cm. It is concluded from the present study that the management of nematode including application of nematicides should be started in the spring season, just prior to the first root flush, to protect the new roots from nematode infection.
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December 2019
Vol. 51, Iss. 6, Pages 1999-2399
