BP Singh

Methods for Detection of Insects and Mites in Imported Germplasm 187acid and 1 part of glycerine (by weight). This renders themsufficiently transparent to reveal internal infestation of larvae,pupae or adults and holes and tunnels made by hatching larvae.The solution is prepared by heating the distilled water and thenadding the rest of the ingredients Kaura (1959).This technique is hazardous to workers due to exposure tofumes of phenol ( a nerve poison) which is a major drawback, ifa large number of seed samples are to be handled. The viabilityis lost and hence .the valuable imported material is unfit forbreeding purposes,- This is a limitation when sample size is verysmall and especially in quarantine where 100 per cent sample isto be examined and cleared for indenter.3. Staining methodStaining methods make use of the capacity of certain dyes tostain the gelatinous egg plugs deposited by the insect on seed orany part of the plant. Some of more successful staining methodsare:a) Adq fuchsin technique for phytophagous chalcidoids : It iswell known that in freshly oviposited green pods, little quantityof watery substances oozes out of the area around the ovipositionpunctures which gradually develops a rust coloured lesion - aminute spot which can be seen with the help of a binocular on theseed coat of infested seeds. In course of time the surrounding seedcoat develops rust coloured lesion which increases in size, as thelarva is full grown the seed attains brownish colour and becomessome what shriveled.The eggs could be detected by making the green pods andseeds transparent in lacto-phenol medium (Koura, 1959) and 3 percent acid fuchsin stain (BDH) added to it. After 24 hrs. eggs couldbe recovered by dissecting the seeds, placed beneath the seed-coatin developing cotyledons or between the two cotyledons near oraround the germpoint (Verma, 1986). Before examinanon underbinocular, the fresh lactophenol medium is to be changed to avoidthe tinting of eggs with chlorophyll.b) Detection oj eggs ,in vegetative propagules : pirectdetermination of the site of egg deposition is difficult in thoseinsects that lay their eggs within plant tissue. The eggs of