Effect of certain systemic nematicides on the interaction between Tylenchulus semipenetrans and Acaulospora trappei on sour orange and Cleopatra mandarin

Abstract

In a pot experiment sour orange was more susceptible to the citrus nematode Tylenchulus semipenetrans than Cleopatra mandarin. The presence of the V A mycorrhizal fungus Acaulospora trappei reduced the numbers of nematode juveniles on sour orange and Cleopatra mandarin roots by 42% and 43% respectively. Chemical control of the citrus nematode with the nematicides aldicarb, oxamyl and phenamiphos was more effective in the presence of mycorrhizae. The nematicides also decreased the number of mycorrhizal spores in the soil and roots. A. trappei alone or in combination with the citrus nematode caused a significant increase in the length, fresh and dry weight of shoots and roots of the two rootstocks.