| Publication Type: | Journal Article |
| : | 1988 |
| Authors: | K. De, Pande Y. D. |
| Journal: | Entomon |
| Volume: | 13 |
| Pagination: | 17-24 |
| Type of Article: | Article |
| : | 0377-9335 |
| : | Sternochetus gravis (Fabricius) occurred as a serious past of mangoes and was distributed throughout Tripura [India], a state adjoining Bangladesh. The life-history of the weevil was studied on Mangifera indicafruits at different temperatures in the laboratory at Agartala during 1982-1984. The reproductively immature adults overwintered inside seeds or other protective places during May-February. The females outlived the males and the survival period varied from 82.2 to 135 days. Provision of food significantly increased the longevity of female only. The weevils undertook short flights only along a horizontal plane. The ratio of males to females was approximately 1:1.4. Mating occurred 10 to 15 days after termination of hibernation and lasted 19 to 22 minutes. Oviposition occurred from March to May on immature mango fruits. No other material was found suitable for successful hatching of eggs. Eggs were laid singly on the surface of fruits. The process of egg laying was quite peculiar. The mean egg size was 0.6 mm in length. Eggs hatched after 4 to 65 days and the larvae fed on cotyledons or pulp. They underwent five identifiable instars. Pupation occurred in mango flesh and seed and occupied 7 to 10 days. Larval maturity was influenced more by different temperature regimens than other stages. One complete life-cycle occupied on an average 41.2, 41.6 and 48.3 days at 22 .+-. 3.degree. C, 24 .+-. 3.degree. C and 27 .+-. 2.degree. C respectively. The species was univoltine. A new host of the pest species, M. sylvatica was recorded. Three species of ants, viz., Oecophylla smaragdina, Camponotus sp. and Monomorium sp. were predators and fungus Aspergillus sp. and mite Rhizoglyphus sp. ectoparasitized the larvae, pupae and hibernating adults. |