Influence of leaf-vein characteristics on oviposition preference of the cotton leafhopper, Amrasca devastans | [Influence des caractérisqtiques des nervures des feuilles sur la préférence de ponte de Amrasca devastans]
1999
Sharma, A. ((Agricultural University, Hisar (Inde). Department of Entomology)) | Singh, R.
Oviposition preference of the cotton leafhopper, Amrasca devastans (Distant) was investigated in relation to leaf-vein characteristics of 12 host plants viz: okra, cotton, castor, cowpea, pigeonpea, sesame, egg plant, cluster bean, green gram, shoe flower, country mallow and portia tree. Observations on the oviposition of the leafhopper under no choice conditions were recorded on three occasions during the peak period of leafhopper incidence in the field. On all three occasions the leafhopper rejected green gram, shoe flower and portia tree for egg-laying thereby indicating non-acceptance of these plants for oviposition. For the remaining plants, the number of eggs per leaf differed significantly. Okra received the maximum number of eggs. Lateral veins of castor, cotton, cowpea, egg plant and country mallow leaves received more eggs in comparison to the main vein and sub-veins whereas in okra the sub-veins received the highest number of eggs followed by lateral and main veins. Correlations of trichome density with the number of eggs laid in different veins were non-significant. Likewise trichrome length had no influence on oviposition by the leafhopper. All types of veins in okra leaves were thicker than the rest of the host plants which might have stimulated more egg-laying in okra. Thickness of each category of vein viz: main vein (r = 60), lateral veins (r = 0.65) and sub-veins (r = 0.56) was found to be positively correlated with the number of eggs laid. Length of main and lateral veins were also found to be positively and significantly related to the number of eggs laid. It may be concluded from the present investigations that leaf vein thickness and length are crucial factor in influencing oviposition behaviour of the cotton leafhopper
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