Feeding and oviposition deterrent activities of microencapsulated cardamom oleoresin and eucalyptol against Cydia pomonella

Abstract

Behavioral manipulation of insects with spice-based deterrents may provide an alternative control strategy. Microencapsulation technology could lead to more effective use of spice essential oils and oleoresins in the field by extending their residual activity. The feeding and oviposition deterrent potential of the microencapsulated cardamom (Elettaria cardamomum [L.] Maton) oleoresin (MEC-C) and eucalyptol (MEC-E) were evaluated against codling moth, Cydia pomonella Linnaeus, 1758. MEC-C capsules contained both 1,8-cineole and a-terpinyl acetate, whereas MEC-E capsules contained only 1,8-cineole. In larval feeding bioassays, MEC-E exhibited the lowest feeding deterrent activity (33%) while MEC-C at 100 mg mL(-1) had the highest (91%). The highest oviposition deterrence activity against gravid females was also shown by MEC-C at 100 mg mL(-1) with 84% effective repellency. In 2010 and 2011, two apple orchards were divided into four 1 ha blocks and sprayed with the following treatments in ultra-low volume sprays: (a) MEC-E at 100 g L-1, (b) MEC-C at 50 g L-1, (c) MEC-C at 100 g L-1, and (d) MEC-pyrethrin at 15 mL L-1. Water-treated abandoned orchards were used as negative controls. Moth catches were monitored weekly using Ajar traps baited with the combination of codlemone, pear ester, and terpinyl acetate. Based on pooled data, mean cumulative moth catch per trap per week was significantly higher in the MEC-E blocks (26.3 male and 13.5 female moths) than those in other treatments except the abandoned blocks. At mid-season and pre-harvest damage assessment, the percentage of infested fruits with live larvae in the high dose MEC-C-treated blocks was reduced to 1.9% and 2.3% in 2010 and to 1.1% and 1.8% in 2011, respectively. Since fruit damage exceeded the economic damage threshold of 1%, high-dose MEC-C treatment may only offer supplementary protection against codling moth in integrated pest management programs.