Acaricidal activities of wild plant extracts against Luciaphorus perniciosus Rack (Acari: Pygmephoridae) and Formicomotes heteromorphus Magowski (Acari: Dolichocybidae)

Abstract

The acaricidal activities of methanol, dichloromethane and hexane extracts obtained from leaves of eight wild plants, Justicia adhatoda L., Momordica charantia L., Embelia ribes Burm.f., Commelina diffusa Burm.f., Litsea cubeba (Lour.) Pers., Ageratum conyzoides L., Galinsoga parviflora Cav. and Bidens pilosa L. were tested against the mushroom mites, Luciaphorus perniciosus Rack and Formicomotes heteromorphus Magowski by a filter paper contact toxicity bioassay. Based upon 24 h LD50 values, the dichloromethane extract of J. adhatoda was the most toxic to L. perniciosus (17.44 mg/cm2), followed by the hexane extract of the same plant (19.27 mg/cm2) and the methanolic extract of L. cubeba (19.58 mg/cm2). In contrast, these extracts had a comparatively low activity against F. heteromorphus. Most toxic to F. heteromorphus was the hexane extract of L. cubeba (27.99 mg/cm2), followed by the methanol and dichloromethane extracts of this plant (29.83 and 39.25 mg/cm2, respectively). These results suggest that extracts of J. adhatoda and L. cubeba have potential to be used as botanical pesticides to control mushroom mites.