FOLIAR BIOCHEMICAL CHANGES DURING GALL FORMATION IN MITRAGYNA PARVIFOLIA

Mitragyna parvifolia is a medicinally important plant which is native to India and Shrilanka. This plant is widely used by tribal people of Rajasthan and other Ayurvedic practitioners. Normal leaf and leaf gall of Mitragyna parvifolia were collected and categorized in normal (healthy leaf) and galled leaf. In the present investigation an attempt was made to study the changes of some metabolites during the gall formation on leaf of Mitragyna parvifolia attacked by gall insect. Total soluble sugar, total phenol and peroxidase activities were found high in gall leaves as compared to healthy leaves but chlorophyll contents and polyphenol oxidase activities were recorded high in normal leave and protein contents were slightly high in normal leaves as compared to infected or gall leaves.

Gall Insect Menace in Eucalyptus

Altogether about 920 species of insects recorded from Eucalyptus worldwide, about six species are gall insects. Of these, Leptocybe invasa, is a major nursery pest of Eucalyptus, exclusively responsible for gall formation in seedlings and saplings, including coppice shoots. The insect has threatened Eucalyptus propagation in nursery stage. The present paper has reviewed succinctly the insect pests of Eucalyptus with special emphasis on gall insect, Leptocybe invasa Fisher & LaSalle (Hymenoptera : Eulophidae), its seasonal occurrence, nature of damage, host plants and description of gall insect, developmental stages of gall, natural enemies and management. The paper has highlighted the need for long term strategies to combat against this severe pest to prevent its spread.

Oxidative stress and antioxidants in overwintering larvae of cold-hardy goldenrod gall insects

Antioxidant and pro-oxidant systems were studied in overwintering larvae of two cold-hardy gall insect species, the freeze-tolerant fly Eurosta solidaginis and the freeze-avoiding moth Epiblema scudderiana. An increase in the levels of the oxidized form of glutathione suggested slight oxidative stress in both species during the winter. Freeze-tolerant Eurosta solidaginis larvae generally had decreased activities of antioxidant enzymes in the winter, indicating that these larvae do not face increased challenge from oxidative stress during the numerous freeze-thaw events they experience. Instead, existing defences must be sufficient to prevent any damage. By contrast, increased winter activities of antioxidant enzymes in freeze-avoiding Epiblema scudderiana suggest that these larvae must defend against the formation of reactive oxygen species. This may result from the oxidative nature of winter metabolism in these larvae, as well as a dependence on lipid oxidation as their fuel over this season. Xanthine dehydrogenase activity decreased dramatically in both species during the autumn, reducing the potential for the formation of the pro-oxidant xanthine oxidase. Indeed, xanthine oxidase activity fell to undetectable levels by winter in Epiblema scudderiana and was not detectable at any time in Eurosta solidaginis.

The insect galls on willow

SynopsisA provisional species list for the insects galling willow in Britain is presented. Aspects of willow biology which may be important in gall-insect species diversity are briefly discussed and the process of gall formation is reviewed for one species of willow-galling sawfly. An experiment investigating willow defences against galling, by measuring phenolic levels in plant and gall tissue, is also described.