Effect of combined application of Pseudomonas fluorescens CHA0 and chemical fertilizers on the activity of root-knot nematode, Meloidogyne incognita, and infected tomato plant in greenhouse*

Effects of chemical fertilizers on Meloidogyne incognita activity and Pseudomonas fluorescens CHA0 were studied in vitro. The results showed that the chemical fertilizers increased 67.0-94.8% mortality of the second stage juveniles and decreased 43.8-80.8% egg hatching of the nematode, but did not inhibit the bacterium growth on NA and LB culture + fertilizer. Effect of combined application of P. fluorescens CHA0 and chemical fertilizers, on the activity of M. incognita and growth indices of infected tomato plant cv. Early Urbana was studied in greenhouse in three turns. Results showed that application of triple superphosphate, sulphur, zinc sulphate and copper sulphate in combination with P. fluorescnse CHA0 significantly increased the growth parameters of tomato plants. In the first trial, combination of the bacterium with 50 mg/kg of nitrogen (urea) caused 54.9% and 67.3% reductions in galls and egg masses/gram of root, respectively, and with 10 mg/kg of phosphorus caused 18% reduction in reproduction factor (RF) of the nematode. In the second trial, the bacterium and 5 mg/kg of cupper caused 83.2% and 80.6% reductions in galls and egg masses/gram of root, respectively, and with 100 mg/kg of nitrogen caused 81.7% reduction in RF. In the third trial, the bacterium and 5 mg/kg of cupper caused 74.7% and 81.2% reductions in galls and egg masses/gram of root, respectively, and with 100 mg/kg of nitrogen caused 67.6% reduction in RF. Combination of P. fluorescens CHA0 and copper sulphate was the best treatment in increasing tomato growth parameters and decreasing the nematode indices.