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This study was conducted to evaluate the bioherbicidal properties of orange peels against canary grass and cheese weed mallow and the response of common bean plants. Two successive pot experiments were conducted with twelve treatments. The first four treatments were applied by incorporating of orange peels powder with the soil surface at successive rates (10, 20, 30 and 40 g/pot) one week pre-sowing of common bean. In the other corresponding four treatments, the orange peels powder was incorporated with the soil surface at the same rates but directly at the same time with sowing of common bean seeds. Additionally, four untreated control treatments were applied for comparison. The recorded results revealed the inhibitory allelopathic effects of orange peels powder on both weeds with direct relationship between the orange peels rate and it's inhibitory effects. However, the pre-sowing treatments were more effective than the others which applied at the time of sowing. Orange peels at 40g/pot at one week pre-sowing gave the highest inhibitory effect on both weeds. This superior treatment subsequently recorded the highest growth parameters and yield traits of common bean. Estimated phenolic compounds, flavonoids and essential oils in orange peels may be responsible for this inhibitory effect. [ABSTRACT FROM AUTHOR]

Allelopathy and natural products are safe non-chemical modern techniques that are applied as alternative to synthetic herbicides for controlling weeds. So, two pot experiments were conducted to evaluate the allelopathic effect of Psidium guajava leaf powder (PLP) and Acetic acid 5% as a natural products on the growth and yield of Capsicum annuum plants and both associated weeds: Phalaris minor (grassy weed) and Malva parviflora (broad-leaf weed). PLP was mixed with in the soil surface at successive rates (15, 30, 45 and 60 g pot- 1). In the corresponding treatments PLP at the same sequenced rates were mixed with the soil then sprayed with acetic acid 5% immediately. Moreover, sole spraying of acetic acid 5% treatment was sprayed on the soil surface. All treatments were applied before transplanting directly. Results revealed that the maximum inhibition of both weeds in both seasons (2018 and 2019) was recorded by PLP at 60g + Acetic acid 5% as compared to unweeded control. Concerning C. annuum growth parameters and yield traits, sole application of PLP at successive rates is more effective than PLP at the same successive rates with acetic acid 5%. So, it was observed that PLP at 60g pot-1 and 45 g pot-1 significantly developed most of growth parameters and yield traits of C. annuum than the healthy plants in both seasons. On the contrary, acetic acid treatment alone recorded the lowest value of all growth parameters and yield traits of C. annuum plants. [ABSTRACT FROM AUTHOR]

Two pot experiments were carried out during two successive winter seasons of (2016/2017) and (2017/2018) at the green house of National Research Centre (NRC), Giza, Egypt. The experiments were conducted to compare the allelopathic effect of Beta vulgaris (shoot and root aqueous extracts at 3%, 6%, 9%) to chemical herbicides (Topik and Basagran) at recommended doses (140 g fed-1 and 1 L fed-1, respectively) in controlling weeds (Phalaris minor and Malva parviflora) associated with Lupinus albus plants. Results showed that all applied aqueous extracts caused reduction in two weeds biomass under investigation. Meanwhile, root aqueous extract was more effective than shoot aqueous extract in controlling weeds. It is worthy to mention that phenolic compounds and flavonoids in B. vulgaris root aqueous extract were higher than that in B. vulgaris shoot aqueous extract. In addition, all applied aqueous extracts increased growth, yield and yield components of L. albus plant. The inhibitory effect of B. vulgaris aqueous extract on weeds or its stimulatory effect on L. albus plants increased by increasing the extracts concentration. The two applied herbicides gave complete eradication of both weeds depending on selectivity of each herbicide followed by root aqueous extract of B. vulgaris at 9%; this in turn reflected on L. albus plants by scoring highest results as compared to unweeded treatment. [ABSTRACT FROM AUTHOR]

Allelopathy is a complex phenomenon which depends on allelochemical concentrations. So, two pot experiments were carried out to investigate the allelopathic effect of alcoholic fresh shoot extract of Eruca sativa (foliar spray) and E. sativa shoot powder (mixed with soil) on Pisum sativum plants and two associated weeds, Phalaris minor and Beta vulgaris. The experiments were conducted in the greenhouse of the National Research Centre, Giza, Egypt during two successive winter seasons (2016-2017 and 2017-2018). Ten treatments were applied in this study. Four treatments were applied before sowing, that E. sativa shoot powder was mixed with the soil at rates of 15, 30, 45 and 60 g · pot-1. The other four treatments of E. sativa alcoholic fresh shoot extract were sprayed twice on both plants and weeds at 5, 10, 15 and 20% (w/v) concentrations. Additionally, two untreated treatments, healthy (P. sativum only) and unweeded (untreated infested P. sativum plants with weeds) were applied for comparison. The results indicated that both alcoholic extracts and powder reduced growth of both weeds. Moreover, there was a direct relationship between concentration and weed reduction. Eruca sativa alcoholic extracts increased yield parameters of P. sativum plants. The maximum yield attributes were recorded by spraying of E. sativa alcoholic extract at 20%. On the other hand, it was clearly noticed that the high powder rates affected negatively P. sativum yield parameters. But the lowest powder rate (15 g · pot-1) stimulated P. sativum yield parameters as compared to unweeded treatment. Chemical analysis of E. sativa shoot powder ensured that the abundant amount of glucosinolates (9.6 μmol · g-1) and phenolic compounds (46.5 mg · g-1) may be responsible for its allelopathic effect. In conclusion, spraying of alcoholic fresh shoot extract of E. sativa at 20% (w/v) and mixing E. sativa shoot powder at 15 g · pot-1can be applied as natural bioherbicides for controlling weeds. [ABSTRACT FROM AUTHOR]