Algal application as a biological control method of root-knot nematode Meloidogyne incognita on cucumber under protected culture conditions and its impact on yield and fruit quality

This study was conducted during seasons 2016 and 2017 to control the root-knot nematode Meloidogyne incognita in cucumber, cultivated in infected soil, using some algal treatments under greenhouse conditions, at Kaha Farm, Qaluobia Governorate, Egypt. Six algal treatments were tested: two foliar applications of Spirulina and Amphora, two drenched soil applications of Spirulina and Amphora, two treatments using Spirulina, as spraying and drenching, and Amphora, as spraying and drenching, in addition to the Rugby nematicide (10% Ebufos, at the rate of 5g/m(2)) and control. Rugby was applied by a soil prepared in its experimental units. After 15days from transplanting, the algal extract treatments were applied twice monthly for 3months. The same concentration (2g/l) of both types of algae was applied in both foliar and drench treatments. The control was sprayed only by water. The results indicated that the soil drenched with Amphora or Spirulina extracts had significant increments in vegetative growth, yield, and fruit quality. In contrast, the control plants had the lowest values in all criteria. Amphora (sprayed with soil drenched) treatment gave 2.5 and 2.69 folds the control in marketable yield in 2016 and 2017 seasons, respectively. The combination of sprayed and soil drenched with Amphora was more effective in nematode's control or in enhancing plant resistance for nematode as shown at most nematode parameters, especially the rate of nematode reproduction factor (RF), which reached 0.42 and 0.45 in both seasons, respectively. It had insignificant differences compared with the nematicide. Therefore, using algae for the biological control of root-knot nematodes is recommended, especially in sustainable agriculture for maintaining the soil and improve fertility.