Sharma, D.R.Devi, Hijam Shila2017-06-032017-06-032014http://krishikosh.egranth.ac.in/handle/1/5810015965The studies on bioecology of citrus psylla, Diaphorina citri Kuwayama were conducted at Punjab Agricultural University, Ludhiana from 2012-2014. The results indicated that the population of citrus psylla was present throughout the year but only adults found surviving from December to February. There was low nymphal population when temperature was > 39°C or < 7°C. Two population peaks of nymphs were bserved, first in April-May and second in August-September. Highest population of adults was found during May. With the decrease in temperature from the end of September, the population of D. citri started to decrease and reached its lowest level during winter season. Correlation analysis indicated that maximum and minimum temperature, sunshine and rainfall were positively correlated with nymphal, adult and mixed population but the effect of rainfall on adult population was non-significant, while relative humidity was negatively correlated. Four predatory beetles were found active during spring (March-April) and autumn (August- September) seasons. There were significant differences in abundance of D. citri on different genotypes/cultivars. A single female, on an average, laid from 329.65 ± 66.72 to 650.55 ± 61.22 eggs on these host plants while the total nymphal period (1st to 5th instar) of D. citri during summer season for both the years was 16.0 ± 1.24, 16.7 ± 1.04 and 17.35 ± 1.09 days on Kinnow, rough lemon and curry leaf, respectively which was shorter than that of spring and autumn seasons. The average female longevity was 42.55 ± 3.32, 41.75 ± 3.87 and 44.1 ± 4.51 days on Kinnow, rough lemon and curry leaf, respectively which was more than male longevity. The adult life span was found more on curry leaf than other two host plants. The morphometric parameters of different stages were also assessed on three host plants. Six generations of D. citri were recorded on Kinnow and rough lemon but there were only 2 generations on curry leaf.enfruits, planting, animal developmental stages, seasons, eggs, biological phenomena, relative humidity, developmental stages, sexual reproduction, diseasesThesis