Abstract
The chemical compositions of the essential oils from the leaves and flowers of Callistemon viminalis and their insecticide and fungitoxic activities were determined. The essential oil was extracted by the hydrodistillation method using a modified Clevenger apparatus. The chemical characterization was performed by GC-MS and GC-FID. The evaluation of the insecticidal activity was performed with the Myzus persicae aphid, and the antifungal potential was determined via the inhibition of the mycelial growth of Alternaria alternata, Fusarium oxysorum and Botrytis cinérea phytopathogenic fungi. The principal components of the essential oils from the leaves and flowers were eucalyptol (84.60% and 61.47%), α-pinene (10.28% and 21.48%) and α-terpineol (2.59% and 2.79%), respectively. The use of a 0.5% concentration of the essential oil from the flowers influenced the preference of aphids and their reproduction. The number of adult aphids decreased within a period of 48 hours in the presence of the essential oil from the leaves. In the test with no chance of choice, the mean number of adults decreased with both oils within 48 hours. No inhibition of the mycelial growth of the A. alternate microorganism was observed in any of the treatments with the two essential oils. However, the growth of F. oxysporum and B. cinerea fungi was inhibited. The mycelial growth of F. oxysporum was inhibited with the concentration of 100 μL·Lˉ1 of the oil from the flowers and 250 μL·Lˉ1 of the oil from the leaves. The inhibition of the growth of B. cinerea was observed at concentrations of 500 and 100 μL·Lˉ1 for the oils from the flowers and leaves, respectively. The essential oils presented insecticidal and antifungal potentials. However, further studies are needed for these oils to be used in integrated pest management.
Highlights
The Myzus persicae Sulzer aphid (Hemiptera: Aphididae), known as the peach aphid, is considered to be one of the most harmful species from an agricultural point of view, affecting several vegetable crops of great commercial importance
The evaluation of the insecticidal activity was performed with the Myzus persicae aphid, and the antifungal potential was determined via the inhibition of the mycelial growth of Alternaria alternata, Fusarium oxysorum and Botrytis cinérea phytopathogenic fungi
In addition to insect attacks, various plant cultures are affected by phytopathogenic microorganisms, of which fungi occupy a prominent place because they are the principal cause of diseases in plants
Summary
The Myzus persicae Sulzer aphid (Hemiptera: Aphididae), known as the peach aphid, is considered to be one of the most harmful species from an agricultural point of view, affecting several vegetable crops of great commercial importance. It is the most important vector of Potato Leafroll Virus (PLRV) in potato crops. This aphid causes direct damage through the continuous suction of the sap from the plant and indirect damage via transmission of the vírus. Their action results in significant losses in production, as well as damage to grains during storage, reduction of nutritional value and even the production of mycotoxins harmful to humans and animals [2] [3]
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