ROOT KNOT (MELOIDOGYNE INCOGNITA) ON LOOFA (LUFFA AEGYPTIACA L.): OCCURRENCE, CONTROL AND FRUITS YIELD

Field surveys were conducted in loofa fields of seven govemorates in 1997 and 1998. Infection percentages were always increased by approximately 3-6 folds by repeatedly using the same soil, although some sanitary measures were adopted. Infection ranges were (13.1-15.3%), (40.8-47.5%) and (79.1­89.1%) in the plants grown for one, two and three successive seasons in the same field soil, respectively. Three nematicides and one biocide (Nemaless) singly and in combina­tions were evaluated against the disease. All treatments effectively reduced number of galls by 20.5-100.0%. egg-masses by 44-100% and second-stage larvae by 25-100% in the root and soil. The highest reduction was obtained with the application of Temik and Nemacur at the rate of 10 gm/plant, while the least was associated with Nemaless or Vydate. In most cases, spraying Vydate on plants grown in Nemacur or Temic-treated soil decreased their positive ef­fectiveness against this nematode. Sufficient increases in fruit yield quantity per plant (20.00-81.25%) and improving in quality by decreasing number of short and medium fruits as well as increasing long ones by 11.11 to 191.65% were recorded. Temik and Nema­cur (10 gm per plant) were the most effective treatments. while, Vydate and Ne­maless were the least. Applying Vydate on loofa plants grown in Temik or Nem­acur-created soil always decreased their efficacy in increasing fruits yield.