Effect of some biological nematicides combined with oxamyl in the control of citrus nematode, Tylenchulus semipenetrans

Abstract

This experiment was carried out to explore the role of two bio-nematicides namely : Mycorrhizae (Arbuscular mycorrhiza) and Nemafree (Serratia marcescens) with oxamyl singly and in combination to control citrus nematode, Tylenchulus semipenetrans under greenhouse conditions. Several methods of control were evaluated, using a chemical pesticide or biological agents (fungi and bacteria), or conducting chemical control, then biological control and vice versa, to determine their efficacy against citrus nematode infecting Valencia orange seedlings. Statistical analysis of the obtained data indicated that the single treatment of the oxamyl nematicide recorded the highest reduction % of citrus nematode larvae reaching (63.8 %), followed by Mycorrhizae (39.5%) and Nemafree (23.1%). The treatment of (oxamyl then Mycorrhizae) recorded the greatest effect in reducing nematode population, where larvae number after 4 weeks of application was 671.9 larvae per 100 cm of soil, as the lowest number of larvae compared to other treatments with a percentage of 48.3% of the total number of larvae, compared with 1300 larvae per 100 cm of soil in control. The treated seedlings with (oxamyl then Mycorrhizae) recorded the lowest number of females in citrus roots , reaching 8.0 female per gram root, with a reduction percentage of 71.4 % compared with other treatments.