Résumé
Afield study was conducted to evaluate the effects of a chemical mixture, biological suspension and synthetic nematicide [oxamyl] on the fruit yield and development of a natural polyspecific microorganism community on cucumber plants. This community included the fungi Aspergillus niger, A. ochracious, A. terreus, Fusarium solani, Penicillium spp., Rhizoctonia solani, and Trichoderma spp.; the dominant bacteria Bacillus spp. and Pseudomonas spp. and the root-knot nematode Meloidogyne incognita. Changes in the density and structure of the community were presented and discussed. Plots treated with the mixture, consisted of red molasses [50 liter], milk [1 liter], smashed garlic cloves [5 kg] and water [45 liter], had the highest fruit yield and lowest M incognita population. Moreover, cucumber yield was significantly [P = 0.01] higher when the mixture was applied at high [16 liter/plot] than medium [8 liter/plot] or low [4 liter/plot] rate. Although the fruit yield of oxamyl-treated plots was not consistent with the applied rates, the medium [120 ml/plot] and high [240 ml/plot] rates showed significantly [P = 0.01] higher yield than plots treated with any of the three doses [0.5, 1 and 2 liter/plot] of the biological suspension having species of Bacillus, Pseudomonas, Rhizobacterium and Rhizobium in almost equal cell- numbers [total of 1.6 x 10[8] bacterial cells/ml water]. Yet, plots treated with the high rate of the suspension [2 liter/plot] yielded more [P = 0.01] fruits than the untreated control. At harvest time, Rhizoctonia solani disappeared while F. solani, was present in a few treatments
Sujets)
Antihelminthiques antinématodes , Tylenchoidea/effets des médicaments et des substances chimiques , Cucumis sativus/croissance et développement , Mélasses , LaitRésumé
Two biological control agents, Nemaless [a commercial suspension of the bacterium Serratia marcescens; 1 x 10 [9] bacterial cells/ml] and Nemastop plus [a commercial suspension presumably of garlic, allium sativum, extract and the fungus Paeciiomyces lilacinus], were tried to determine their effects on cucumber growth parameters and Meloidogyne javanica development and reproduction. Both have significantly [P = 0.05] reduced the rootknot nematode final population on cucumber cv. Royal sluis. The hatching percentages of M.javanica eggs were significantly [P = 0.05] reduced in the Nemaless and Nemastop plus treated soil compared to the control [nematode only]. Nemastop plus was more effective in reducing the nematode population levels than Nemaless. Yet, the two compounds together did not show a synergistic effect on M. javanica final population density but rather showed decrease in the efficacy. The beneficial effects of such biocontrol agents were mirrored by better shoot growth of cucumber cv. Royal sluis in the treated pots