This study focused on the some lethal and sub-lethal bioeffects of essential oil of Eucalyptus floribundi on the adult of Rhyzopertha dominica and Oryzaephilus surinamensis. Further, the chemical composition of this hydro-distillated essential oil was evaluated by GC-MS analysis. LC of E. floribundi essential oil was obtained for R. dominica and O. surinamensis as 34.39 and 43.54 μl/l.air, respectively. LT₅₀ of R. dominica at 100, 200 and 500 μl/l air concentrations was 4.28, 3.92 and 3.13. Accordingly, LT₅₀ for O. surinamensis at the same concentrations was calculated as 4.90, 4.44 and 2.92. The experiment results showed that increasing the concentration of essential oil and the exposure time led to the increases in mortality. According to the repellent index it was found that essential oil at three concentrations of 70, 140 and 280 μl/l air was repellent for both insects. In the analysis of the fumigant toxicity durability, LT of the essential oil on R. dominica was 5.44 days and on O. surinamensis was 11.36 days. The results of anti-nutritional experiment revealed that the increase of essential oil concentration has contributive to the nutritional indexes of O. surinamensis and R. dominica adult. It has been found that the E. floribundi essential oil may produce a great range of bio-effects on R. dominica and O. surinamensis and can be a potent candidate for such insect pest management.

Meloidogyne spp. are important parasitic nematodes affecting a variety of plants worldwide. We investigated the nematicidal properties of specific compounds found in bio-fumigant plants, particularly linalool, nonanal, methylene chloride, and 2-Decanal. Laboratory findings revealed that methylene chloride and 2-Decenal effectively reduced populations of second-stage juveniles (J2s). Additionally, the research explored the effects of tomato (Solanum lycopersicum L.) on M. incognita J2s, observing that tomato leaves significantly increased J2 mortality for all time measurements and different temperatures, while the opposite results were observed for root-stems. In the study, leaf treatment resulted in a maximum mortality response (MR_max) and half-maximal effective concentration (EC₅₀) of approximately 100% and 4.0 µg/mg, respectively, at a temperature of 35 °C by week 8. In contrast, the root-stems treatment showed an MR_max of 13.5% and an EC₅₀ of 3.0 ± 1.7 µg/mg. GC-MS analysis identified key compounds in tomato leaves and root-stems, such as α-pinene, d-limonene, and linalool. The results suggest that tomato leaves have potential as effective bio-fumigants for controlling root-knot nematodes.

The root-knot nematode (Meloidogyne incognita) is a plant pathogen that causes significant economic damage to important food crops. The nematicidal and insecticidal effects of the essential oil and extract of the root and stem of different species of Eupatorium have been studied in several countries. We investigated the impact of root stems and leaves of the E. adenophorum on the second-stage juveniles (J2s) of M. incognita. Nematode mortality decreased by root-stem treatment and increasing temperature and time. Nematodes (J2) were more sensitive to root-stem treatment than leaf treatment at all tested conditions. For example, the half maximal effective concentration (EC₅₀) root-stems at 35 °C was estimated as 10.3 mg/g and in the 8th week as 7.8 mg/g, while the maximal effective concentration (EC_max) in leaf treatment is 20.3 and 10.1 mg/g, respectively. The E. adenophorum 40 mg/g concentration of root stems also produced the highest height of the cucumber stem and the highest cucumber fresh weight in the greenhouse. (E)-beta-farnesene, α-pinene and D-limonene, as the main identified components in fumigant plants, increased the mortality rate of J2s in root-stems treatment. We conclude that E. adenophorum dried root stems added to the soil in greenhouses have the potential as a bio-fumigant for M. incognita management.

Pythium spp. are soil-borne pathogens that cause damping-off and root rot diseases in many plant species such as cucumber. In the current study, the effect of dried roots–stems and leaves of Ageratina adenophora (Sprengel) R. King and H. Robinson (=Eupatorium adenophorum Sprengel) alone and in combination with pyrogenic biomass biochar to control Pythium aphanidermatum (Edson) Fitz was assessed. In four treatments of leaves, roots–stems, leaves + biochar, and roots–stems + biochar, it was observed that the treatment with leaves at an E_max (maximal effective concentration on control fungi) of 79 g/kg of soil had the most antifungal effect on P. aphanidermatum. Also, the C_max (the highest level of control) increased with time and reached 82.4% and 71% on days 30 and 60, respectively. The highest cucumber fresh fruit weight and the highest height of the stems in the greenhouse were observed in leaf treatment of A. adenophora. Biochar did not have any remarkable controlling effect on P. aphanidermatum, and its population increased. The main compounds extracted from the dried leaves and roots–stems of A. adenophora, including α-pinene, nonanone, hexahydronaphthalene, 3-undecanone, muurolene, and heneicosane, had antifungal properties. We concluded that the leaves of A. adenophora have the potential to be used as a bio-fumigant for P. aphanidermatum management.