EFFECT OF PLANT-AGE ON HOST PREFERENCE, HONEYDEW PRODUCTION AND FECUNDITY OF NILAPARVATA-LUGENS (STAL) (HOM, DELPHACIDAE) ON RICE CULTIVARS

Host preference, honeydew production, fecundity and size of egg groups of brown planthopper Nilaparvata lugens (BPH) were studied on 30-, 60- and 90-day-old rice plants of cultivars TN1, ASD7, Mudgo, Babawee, Rathu-Heenati and Ptb33. BPH preferred to infest TN1 and ASD7 to Babawee and Mudgo, while Rathu-Heenati and Ptb33 were non-preferred. In general, plant age within a cultivar did not affect BPH preference, but on Babawee it settled more on 90-day-old plants than on 30- or 60-day-old ones. Honeydew output was high on TN1 and ASD7 and low on Ptb33. On TN1, ASD7 and Mudgo it was lower on 90-day-old than on younger plants, but on Babawee the output was highest on the oldest plants. Over 24 h most eggs were laid on TN1, but there were no differences in egg laying between other cultivars, or between plants of different ages within individual cultivars. Lifetime fecundity was highest on TN1 and low on Ptb33 and Rathu-Heenati. On TN1 and Mudgo fecundity was lowest on 90-day-old plants, but on Babawee it was highest on 90-day-old plants. Plant age did not affect the number of eggs laid on other cultivars. The size of egg groups declined in the order TN1, ASD7, Mudgo, Babawee, Rathu-Heenati and Ptb33, but it was not affected by plant age.