This work was executed during two successive seasons of 2018 and 2019 in the nursery and laboratory of Fac. Agric., Minia Univ., Egypt to investigate the response of vegetative and root growth and some chemical composition of Delonix regia seedlings to four percentages of humic acid (0, 1, 2 and 4%) and four bio-and/or mineral NPK fertilization treatments (control, 100% NPK, Minia Azotein and 75% NPK plus Minia Azotein), as well as, the interaction between them. All used three percentages of humic acid significantly increased vegetative growth (plant height, stem diameter, the aerial part dry weight), root growth (root number and roots dry weight) and chemical composition (photosynthetic pigments, NPK%, total phenolic and total flavonoids contents) over control. Humic acid at 4% more was effective treatment. All used bio-and/or mineral NPK fertilization treatments significantly increased all studied characters over control. The best treatments were 100% NPK or 75% NPK plus Minia Azotein. It could be recommended to add humic acid at 4% in combination with 100% NPK or 75% NPK plus Minia Azotein to improve growth of Delonix regia.

Geranium (Pelargonium graveolens L'Herit ex Ait.) plants infected with root rot and wilt diseases were collected from different locations of Behira, Ismailia and Minia Governorates, Egypt. Fusarium, Macrophomina, Rhizoctonia and Pythium were isolated from the infected plants. The results showed that F. oxysporum recorded the highest isolated rate, followed by R. solani, F. solani, M. phaseolina and Pythium sp. The effect of various concentrations of marjoram and peppermint essential oils on the mycelial growth of the isolated fungi was tested in vitro. Marjoram and peppermint oils completely inhibited the growth of F. oxysporum, F. solani, R. solani and Pythium sp. at the concentration of 5 ml/l. A Field experiment was conducted at the Experimental Farm of Agricultural Research Station, Malawy, Minia Governorate, Egypt, during two successive seasons of 2020 and 2021 to study the effect of different weed control methods (un-weeded control, clover cover yield, hand hoeing and black plastic mulch) on weeds biomass. The results indicated that all weed control treatments significantly decreased the weight of grassy broad-leaf weeds and total weeds compared to the un-weeded control. Moreover, all weed control treatments and plants treated with the essential oils of marjoram and peppermint as well as the biocides (Bacillus subtilis and Trichoderma harzianum) significantly decreased the wilt disease incidence and improved the vegetative growth, yield and volatile oil of geranium plants. The results indicated that plastic mulch was the most effective in reducing wilt incidence as well as increasing all growth characteristics and productivity of volatile oil, while the highest disease incidence and the lowest growth and yield were recorded under un-weeded treatment. The application of the marjoram essential oil or biocide B. subtilis resulted in the lowest incidence of wilt disease and the highest increase in the growth, herb yield, essential oil yield and main components of essential oil. The highest growth characters and volatile oil were recorded with either black plastic mulch and marjoram essential oil or with B. subtilis treatment.