The larval stages of the Lepidoptera need no introduction, their destructive defoliating habits are familiar to anyone who has any connections with plants. Apart from the large conspicuous adults and sometimes larvae of the larger species of moths, there are a huge number of very small species known collectively as microlepidoptera. Some of these have feeding areas away from growing plant material for they inhabit stored grains, processed foods, the contents of birds' nests, etc. Some species attack pods and seeds developing on the plant and these form a transitional group between the true plant feeder and those at the other extreme of the feeding scale.
Collected ripe pods of legumes from Acacia and related genera are frequently found to have been attacked by a species of Lepidoptera. The evidence is usually in the form of partially devoured seeds and the inside of the pod is lined with a mass of silk and faecal pellets. At this stage the larva responsible for the damage has pupated and the adult moth emerged and flown away.
As with the other smaller groups of insects infesting pods of the tree legumes, the biological data is very sparse or non-existent, apart from a handful of species infesting grain legume crops. Members of the Pyralidae and Pterophoridae constitute the majority of the species within the microlepidoptera which attack plants and non-growing hosts so it is within these families that the species infesting pods are likely to be found. They appear to exhibit less host specificity than do the beetles. For example, one of the pod borers, Maruca testulalis, a member of the Pyralidae, now found in most tropical regions of the world where grain legumes are grown, attacks, according to Taylor (1978) no less than 24 species of legumes and 2 non-leguminous hosts. In India and parts of South East Asia a number of species of the Olethreutidae are recorded as attacking stems, pods and seeds of legume crops. All of these groups may prove to be capable of attacking developing pods of tree legumes. An extensive trapping and breeding programme is necessary to establish the species involved.
