A. A. Buhroo , M. Z. Chishti , M. Amin Masoodi

Abstract

Studies on the seasonal population trends of Scolytus nitidus on apple trees indicated adult emergence from middle of April to middle of October with two marked peaks of swarming in April-May and in July. The adults generally appeared on wing during the day time. The emergence was maximum in the second fortnight of July. There was also a third partial generation but the third time swarming was not clearly demarcated in nature mainly due to the fact that all the individuals of second brood could not complete their development and the second swarming beetles emerged for a prolonged period overlapping with the third time emergence. The emergence period for one brood lasted for 87 days. The peaks of beetle populations were found to be correlated with higher temperatures. The emergence started at a monthly maximum mean temperature of 22.5°C and minimum mean temperature of 8.3°C around the middle of April.

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M. Amin Masoodi

Abstract

Biological studies of Lymantria obfuscata Walker showed that male moths after eelosion are attracted to female moths and copulation lasts for 1 hour to 2.05 hours. After preovipositional period of 1.05 to 6.05 hours on an average 462.3 globuler light pinkish eggs were laid in the Iirst week of June in a period of 3 to 6 days in the form of yellowish oval egg masses covered with a coating of yellowish brown hairs. Average incubation period was 302.80 days and hatching started in the last week of March. There were five larval instars and the total larval period lasted for 45.77 days and 49.50 days for males and females respectively. Full fed larvae spun few strands of silk and remained in prepupal form for a period of two to three days before transforming into reddish brown pupae. Male pupae were relatively smaller in size than the female ones and lasted for 14.37 and 10.42 days respectively. Eclosion of adults was diurnal. The dirty creamy white female moths were too heavy and unable to fly. Male moths were respectively small, darker in colour and flying during day. Male and female moths lived for 5.33 and 8.73 days respectively and there was no significant variation in the longevity of adult moths when provided with 5 per cent honey solution. There was only one generation of the pest in a year.

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