Pomegranate (Punica granatum L.) growth and biochemical alterations in response to meloidogyne incognita infection, minerals, and nano-fertilizers

The effects of four inoculum levels (500, 1,000, 2,000, or 4,000 second-stage juveniles (J2) per plant) of the root-knot nematode, Meloidogyne incognita, on two pomegranate cultivars (‘Manfalouty’ and ‘Wonderful’) were investigated under greenhouse conditions in response to plant inorganic and organic chemical concentrations. Furthermore, the effects of six commercial chemical fertilizers (inorganic fertilizers and nano-fertilizers) on plant growth and nematode reproduction were also studied. Both cultivars recorded the highest gall formation, embedded stages, and final nematode population at the inoculum dosage of 2,000 J2/plant. The highest reproductive rate was achieved with 500 J2/plant, while the lowest rate was observed with 4,000 J2/plant on both cultivars. ‘Wonderful’, at all M. incognita inoculum levels, was more sensitive to nematode infestation than ‘Manfalouty’. ‘Wonderful’ showed a greater reduction in fresh and dry plant weights than ‘Manfalouty’ at 2,000 and 4,000 J2/plant. In both cultivars, the concentrations of N, P, and    K decreased with increasing nematode inoculum levels. This decline was more pronounced in ‘Manfalouty’ than in ‘Wonderful’. The nano-fertilizers, Hyper Feed®, and Hyper Feed Solo® reduced all nematode parameters but only in ‘Wonderful’. Treatment with Hyper Feed® resulted in the highest percentage increases in all plant growth parameters in ‘Wonderful’. Total carbohydrate concentration was increased in ‘Manfalouty’ treated with the nano-fertilizers, especially with Hyper Feed®. Also, concentrations of total phenols and tannins increased in ‘Wonderful’ when treated with either nano-fertilizer. Generally, both nano-fertilizers showed an increase in plant N levels. We recommend using nano-fertilizers in integrated pest management (IPM) programs on pomegranate where they improved plant growth parameters and reduced nematode multiplication parameters more markedly than inorganic fertilizers.