Roles of Oxalic and Malic Acids in Chickpea Trichome Exudate in Host-Plant Resistance to Helicoverpa armigera

Abstract

Abstract-Effects of malic acid and oxalic acid on oviposition of Helicoverpa armigera were investigated in a laboratory cage choice experiment. Malic acid stimulated oviposition at a concentration of 0.6 ^imol/cm2 but inhibited it at 3.4 fimol/cm2. Oxalic acid showed neither stimulation nor inhibition of oviposition at 0.25-1.7 /^mol/cm2. Correlations between the amount of these acids in trichome exudate on leaf and pod surface and H. armigera populations and pod damage were investigated in a field experiment using 14 chickpea genotypes. Malic acid on the leaves stimulated oviposition during the vegetative and flowering stages, when its concentration was 0.1-0.7 ^mol/cm2. Later, during the podding stage there was no significant correlation between either egg density or pod damage and malic acid levels. However, there was a significant negative correlation between pod damage and oxalic acid levels. Oxalic acid, which had been reported to have an antibiotic effect on H. armigera larvae, has an important role in resistance to this pest in chickpea. The length of the podding period was also a factor influencing the extent of pod damage; a longer podding period resulted in prolonged exposure to H. armigera attack and more pod damage.

Expression of resistance to the pod borer Helicoverpa armigera (Lepidoptera: Noctuidae), in relation to high-performance liquid chromatography fingerprints of leaf exudates of chickpea

“…Oxalic acid inhibits the growth of H. armigera larvae when incorporated in artificial diet, while malic acid shows no such effects (Yoshida et al, 1995(Yoshida et al, , 1997. Acetic acid showed a negative association with larval weight gain, and H. armigera damage rating at flowering and at maturity, while citric acid showed a negative and significant association with leaf damage at flowering.…”

Interaction between host plant resistance and biological activity of Bacillus thuringiensis in managing the pod borer Helicoverpa armigera in chickpea

“…However, C 235 also resulted on adverse effects on H. armigera in combination with Bt, although it had low amounts of oxalic acids, but considerably high amounts of malic acid in the leaf exudates. Expression of resistance to pod borer, H. armigera is influenced by the pH and amounts of malic and oxalic acids in the leaf exudates (Bhagwat et al, 1995;Yoshida et al, 1995Yoshida et al, , 1997 and reduced larval and pupal weights and prolonged larval and pupal periods have been observed in insects reared on leaves, pods and in artificial diets impregnated with lyophilized leaves and pods of H. armigera-resistant genotypes of chickpea as compared to those of the susceptible ones (Sreelatha, 2003;Narayanamma et al, 2008 Figures followed by the same letter within a column do not differ significantly at P < 0.05. -= There was no larval survival.…”

Physiological characteristics of the Large Copper butterfly, Lycaena dispar (Lepidoptera: Lycaenidae)

“…The family Polygonaceae, to which Rumex belongs, is reported to contain high levels of oxalates (Libert and Franceschi, 1987). These compounds, can act as a feeding deterrent to many herbivores (Bink, 1970(Bink, , 1986Libert and Franceschi, 1987;Yoshida et al, 1997;Yoshihara et al, 1980). Because the final-instar larvae of L. phlaeas can use R. crispus and R. acetosa, it is probable that the oxalates present in these plants have little or no harmful effect on L. phlaeas larvae and that allelochemicals may not be the reason that other Rumex species are not used as host plants.…”