Biological Control of Insect Pests: Southeast Asian Prospects - EcoPort

108 Biological Control of Insect Pests: Southeast Asian Prospects
Host plants
cages in Papua New Guinea, larvae pupated in strongly spun cocoons
covered with particles of chewed wood, suggesting that pupation on bark
may occur in the field. In India, Sengupta and Behura (1955, 1957) record
pupation generally inside the fruit, the moth emerging through an exit hole.
The pupal period lasts from 9 to 14 days, so that the total period from egg to
adult takes from 28 to 41 days. Adult longevity is 8 to 9 days. Adult males
can be distinguished from females by having expanded dark brown, hairy,
mesothoracic tibiae (Leefmans and Van der Vecht 1930; Vožte
1936;
Kalshoven 1981; Fenner 1987, 1997; Golez 1991a).
Adults are generally nocturnal and, during the day, spend most of their
time resting under leaves on the tree. They are seldom attracted to light.
Females prefer to oviposit on fruit protected from direct light. Newly
hatched larvae stay together and tunnel into the fruit near where the eggs
were laid. If later instar larvae are crowded, some may leave by suspending
themselves on silken threads, which also facilitate transfer to other fruits. A
shorter developmental period was observed for both males and females
reared on the pulp than on the seed of carabao mangoes, although those
reared on the seeds were larger and lived longer, females producing more
eggs. Development differed slightly on different mango varieties (Golez
1991a).
In cages in Papua New Guinea only a small proportion of pupae yielded
adults in the several months after pupation, suggesting a pupal diapause
which may synchronise the life cycle with the seasonal fruiting of its host
(Fenner 1987, 1997).
The commonest host, wherever D. sublimbalis occurs, is Mangifera indica,
but there are records also from M. odorata in Papua New Guinea and
Indonesia from M. minor in Papua New Guinea (F. Dori pers. comm. 1997).
and from Bouea burmanica in Thailand (Beller and Bhenchitr 1936). All
four belong to the family Anacardiaceae (Sengupta and Behura 1955;
Kalshoven 1981; M. Schaffer pers. comm. 1997). Larvae are unable to
develop on parts of the mango tree other than the fruit, or in the fruit of
avocado, chico, guava, jackfruit, papaya, santol, sineguelas or star apple
(Golez 1991a). However, as the genus Mangifera contains many species it is
quite possible that further wild hosts will be found (Fenner 1997). Indeed the
label data, quoted earlier, on specimens collected well outside the major
fruiting season of M. indica suggests that this may well be so. The genus
Mangifera contains about 62 species of tall evergreen trees which are native
to the area stretching from India to Papua New Guinea, with the greatest