Bio-nematicidal properties of some citrus peel extracts against the golden potato cyst nematode, Globodera rostochiensis (Wollenweber, 1923) behrens, 1975 (Tylenchida: Heteroderidae)

Abstract

The extracts of peels of kumquat, pomelo and bergamot showed significant bio-nematicidal effect against Globodera rostochiensis second-stage juveniles after 48h application. The bio-nematicidal activity was very low in all the extracts of fresh peels but was greatly increased in the extracts of stored pulped peels with 92.4 %, 94.8 % and 86.4 % mortality of nematodes for kumquat, pomelo and bergamot respectively. The data showed that essential oils from citrus peels may have been released in the extracts during storage of the pulped citrus peels. The egg hatch inhibition of the extracts from stored pulped citrus peels was 86.3 %, 93.3 % and 81.1 % for kumquat, pomelo and bergamot respectively. The reversibility tests revealed that the effect of citrus extracts on the hatch of eggs was not permanent. The hatching partially resumed after the removal of the citrus peel extracts but was still significantly lower than the control group. The infection of Globodera rostochiensis second-stage juveniles on potato seedling roots was significantly inhibited by the extracts of the cooler-stored pulped peels of kumquat, pomelo and bergamot. The results support the use of biologically derived preparations with almost no side effects, as an alternative to chemical preparations that have serious adverse effects on the environment and human health in agricultural pest control.