Biological Control of Insect Pests: Southeast Asian Prospects - EcoPort

Major natural enemies
4.2 Anomis flava 31
Apanteles anomidis Hym.: Braconidae
A. anomidis is an important endoparasite of A. flava in China. It has one
generation a year. A mated female lays an average of 109 eggs and prefers to
lay in 1st to 3rd instar host larvae. Adults fed on 10% aqueous sugar solution
lived about 1.5 days at 29¡C (Xiong et al. 1994). An average of 13.7 pupae of
A. anomidis were obtained from each parasitised A. flava larva (Xie 1984).
Palexorista quadrizonula Dip.: Tachinidae
This parasitoid was the most important of 4 species attacking A. flava in
Tanzania. It is widespread in Africa south of the Sahara and occurs also in
the Seychelles and St Helena. It attacks a range of lepidopterous larvae,
especially species belonging to the Noctuidae, but also to the Arctiidae,
Geometridae, Pyralidae and Tortricidae. In A. flava it produces 1 to 5
puparia from each larva, with an average developmental period of 7.9 days
(Crosskey 1970; Robertson 1973).
Discussion
Many natural enemies of A. flava have been reported, although there have
been few studies detailed enough to indicate their true effectiveness. Most of
the parasitoids are unlikely to be specific to A. flava, but to attack also other
lepidopterous larvae feeding on the same host plants. Most of these other
hosts are themselves pest species, whose abundance it is desirable to lower.
Specificity in these circumstances is rather to lepidopterous larvae in a
particular habitat and the parasitoids may thus be sufficiently restricted in
their attack on non-target species to be seriously considered as agents for
classical biological control. Indeed, for a sporadic pest such as A. flava, it is
highly desirable that there should be readily available a reservoir of natural
enemies present continuously, so as to be in place when populations of
A. flava start to increase.
The reasons for sporadic outbreaks have not been identified, although
Brader (1966) suggested that it might well be due to the application of
insecticides resulting in the death of natural enemies.