Life cycle of gundhi bug Leptocorisa oratorious F on alternate host Echinochloa colonum L under laboratory condition

Abstract

Studies on biology and morphometry of paddy earhead bug, Leptocorisa oratorius F (Hemiptera: Alydidae) were carried out on its alternate host Echinochloa colonum L in the laboratory of Bihar Agricultural University, Sabour, Bhagalpur, Bihar in the year 2016. The study revealed that the eggs had an incubation period of 7.81±0.87 days which ranges from 7-9 days. The nymphs were observed to pass through five instars where the insects moulted between each stages and the duration of each instars was 3.4±0.84, 3.9±0.87, 3.9±0.87, 3.9±1.10 and 4.2±1.03 days for I, II, III, IV and V instars respectively. The total nymphal period was observed to be ranged between 14-26 days whereas the total developmental period from egg to adult was ranged between 21-35 days. Eggs were laid singly, in clusters or in a linear fashion with an average fecundity of 75-135, and the linear pattern found most common, under laboratory condition on the E. colonum L. The longevity of adult male and female was observed to be considerably different and it was ranged from 17-30 days and 45-62 days for male and female respectively. The length and width of the eggs were ranged from 0.76 to 1.2 mm (0.94±0.09) and 0.45 to 0.83 mm (0.64 to±0.10) respectively. The adult females were measured to be 15.8 to 17.5 mm (16.58±0.57) in length and 2.00 to 3.00 mm (2.69±0.34) in width whereas the length and width of males were observed to be slightly smaller and were varied from 14.00 to 15.50 mm (15.06±0.49) and 1.6-1.8 mm (2.36±0.27) respectively. The demonstration of all the stages of L. oratorius development on alternate host should make this notorious pest easy to be identified and this knowledge can allow for timely and effective management, thus a reduction in the qualitative and quantitative losses on the yield of rice.