Biological Control of Insect Pests: Southeast Asian Prospects - EcoPort

4.11 Leucinodes orbonalis 193
Itamoplex sp. Hym.: Ichneumonidae
Adult Itamoplex sp., 8 to 10 mm in length, were reported from Kulu Valley,
Himachal Pradesh, India where the winter temperature drops as low as Ð8¡C.
L. orbonalis overwinters in the larval (?prepupal) stage in an earthen cocoon
attached to the host plant, usually 1 to 3 cm below the soil surface. The
parasitoid emerged from 9% to 15% of these cocoons. Itamoplex (= Cryptus)
sp. is recorded attacking a range of host Lepidoptera in cocoons (Verma and
Lal 1985).
Trathala (= Cremastus) flavoorbitalis Hym.: Ichneumonidae
This is a widespread, non-specific parasitoid of lepidopterous larvae. It
occurs naturally in India, Japan, Myanmar, Sri Lanka, the Philippines and
Singapore and has been established in Canada, Hawaii and continental USA
for biological control of several important lepidopterous pests. It is recorded
from at least 5 families of Lepidoptera, involving over 40 different hosts,
most of them pest species (Bradley and Burgess 1934). It is not known
whether there are strains that prefer to attack particular hosts.
T. flavoorbitalis is recorded from L. orbonalis in India and also in Sri
Lanka where L. orbonalis is its major host and where an average
parasitisation level of 36.2% is reported (Sandanayake and Edirisinghe
1992, 1993). In Hissar, India, Trathala was the only parasitoid of
L. orbonalis, with levels of attack on larvae ranging from 13.2% to 18.2% in
winter to 12.9% in summer at a time when 95.2% of fruit was infested
(Naresh et al. 1986a, b).
T. flavoorbitalis females commence ovipositing 4 days after emergence,
with a preference for 3rd, 4th and 5th instar host larvae. In the laboratory,
only a fraction of 1st instar larvae are stung and all soon die from the
encounter, a fate shared by about half the 2nd instar larvae that are stung. In
later instars 68Ð91% were stung, but without early mortality. Not all of these
received eggs, although some received up to 5, with only one parasitoid larva
developing beyond the first instar. Parasitoid development time from egg to
adult was about 23 days at 28¡C. Successful development occurred in 53%
of the 3rd, 57% of the 4th and 41% of 5th instar host larvae, adult wasps
emerging after pupation of the host. In the field, the parasitoid attacks the
host larva by inserting its ovipositor into the hole bored into the fruit and
through which the larva pushes out frass (Bradley and Burgess 1934; Naresh
et al. 1986a; Sandanayake and Edirisinghe 1992, 1993).