• Korean journal of applied entomology
• /
• v.46 no.1 s.145
• /
• pp.57-62
• /
• 2007

Reproductive incompatibility is an Important factor to select a specific biologlcal control agent for successful augmentation of the corresponding endogenous population. An endoparasitoid, Cotesia plutellae (Kurdjumov), is an effective control agent to diamondback moth, Plutella xylostella (L.) and has been known to be classified into two groups in terms of reproductive incompatibility. This study analyzed an Korean population of C. plutellae in terms of morphological characters and mitochondrial DNA marker, which did not match with either of two reproductive incompatibility groups. These results suggest that a Korean population of C. plutellae can be involved in a novel reproductive group. For any augmentation program of C. plutellae in Korea, reproductive incompatibility should be seriously considered to select a particular exotic population.

• Proceedings of the Korean Society of Applied Entomolohy Conference
• /
• 2005.05a
• /
• pp.198-198
• /
• 2005

• Proceedings of the Korean Society of Applied Entomolohy Conference
• /
• 2005.05a
• /
• pp.185-185
• /
• 2005

• Korean journal of applied entomology
• /
• v.43 no.3 s.136
• /
• pp.225-231
• /
• 2004

An endoparasitoid wasp, Cotesia plutellae, has been used for a biological control agent against the diamondback moth, Plutellae xylostella. It has a symbiotic polydnavirus in their reproductive tract, which is required for its successful parasitization. Here, we measured a specific replication time of the polydnavirus during female development of C. plutellae. We, also, analyzed the reproductive potentials of female C. plutellae under mating or different host conditions. At $25^{\circ}C$, pupal C. plutellae began to develop adult tissues such as compound eyes and wings since day 2. At day 5, all adult tissues including antennae were developed and were ready to emerge. With polyclonal antibody raised against C. plutellae polydnavirus, an immunobloting could confirm virus replication at day 4 during pupal stage. Virus particles could be visualized by transmission electron microscope in the oviduct lumen of day 5 pupae. After adult eclosion, venom gland and ovarian calyx increased in size, though ovarioles did not. Mated females layed large number of eggs (over $60\%$) at first 4 days during their mean longevity of ca. 8 days at $25^{\circ}C$. Unmated females showed less active ovipositional behavior, where all the eggs developed into males. C. Plutellae parasitized both P. xylostella and fall webworm, Hyphantria cunea. However, C. Plutellae developed faster and showed higher successful paarasitization in P. xylostella than in H. cunea.

• BMB Reports
• /
• v.44 no.6
• /
• pp.393-398
• /
• 2011

Polydnaviruses are a group of double-stranded DNA viruses and are symbiotically associated with some ichneumonoid wasps. As proviruses, the replication of polydnaviruses occurs in the female reproductive organ at the pupal stage. This study analyzed the effects of two developmental hormones, juvenile hormone (JH) and ecdysteroid, on the viral replication of Cotesia plutellae bracovirus (CpBV). All 23 CpBV segments identified contained a conserved excision/rejoining site ('AGCTTT') from their proviral segments. Using quantitative real-time PCR based on this excision/rejoining site marker, initiation of CpBV replication was determined to have occurred on day 4 on the pupal stage. Pyriproxyfen, a JH agonist, significantly inhibited adult emergence of C. plutellae, whereas RH5992, an ecdysteroid agonist, had no inhibitory effect. Although RH5992 had no effect dose on adult development, it significantly accelerated viral replication. The results of immunoblotting assays against viral coat proteins support the effects of the hormone agonists on viral replication.

• Proceedings of the Korean Society of Applied Entomolohy Conference
• /
• 2005.05a
• /
• pp.105-105
• /
• 2005

• Proceedings of the Korean Society of Applied Entomolohy Conference
• /
• 2005.05a
• /
• pp.108-108
• /
• 2005

• Proceedings of the Korean Society of Applied Entomolohy Conference
• /
• 2005.05a
• /
• pp.109-109
• /
• 2005

• Korean journal of applied entomology
• /
• v.45 no.3 s.144
• /
• pp.375-380
• /
• 2006

A solitary endoparasitoid, Cotesia plutellae, parasitizes diamondback moth, Plutellae xylostella. It has been suggested that its antennae are a major sensory organ to search host and recognize host developmental and other physiological condition during parasitization. This research was performed to understand the parasitic behavior of C. plutellae by analyzing sensory types and their numbers on the antennae using scanning electron microscope. There was no significant difference in antennal length in both male and female C. plutellae, in which both sexes had 16 flagellomeres. Three different types of sensilla (trichoid, seta, and placodea sensilla) were located mostly on flagella and analyzed in their density on the different antennomeres. Trichoid sensillum was the major sensory type and showed about 87% density among all sensilla. Both trichoid and placodea types of sensilla exhibited even numbers on all flagellomeres with some decrease at terminal segments. In contrast, seta form of sensilla showed drastic increase in its density at distal part after 9th flagellomere. When distal half of flagellomeres were cut off, the C. plutellae could not parasitize host larvae. Even when only four distal flagellomeres were removed, the parasitism showed only 30%. These results indicate that C. plutellae antennae are required for parasitism and suggest that seta form of sensilla may play significant roles in recognizing host for parasitization.

• Journal of Microbiology and Biotechnology
• /
• v.19 no.6
• /
• pp.610-615
• /
• 2009

As a provirus, polydnavirus has a segmented DNA genome on chromosome(s) of host wasp. It contains several genes in each segment that presumably play critical roles in regulating physiological processes of target insect parasitized by the wasp. A cysteine-rich protein 1 (CRP1) is present in the polydnavirus Cotesia plutellae bracovirus (CpBV) genome, but its expression and physiological function in Plutella xylostella parasitized by the viral host C. plutellae is not known. This CpBV-CRP1 encoding 189 amino acids with a putative signal peptide (20 residues) was persistently expressed in parasitized P. xylostella with gradual decrease at the late parasitization period. Expression of CpBV-CRP1 was tissue-specific in the fat body/epidermis and hemocyte, but not in the gut. Its physiological function was analyzed by inducing transient expression of a CpBV segment containing CpBV-CRP1 and its promoter, which caused significant reduction in hemocyte -spreading and delayed larval development. When the treated larvae were co-injected with double-stranded RNA of CpBV-CRP1, the expression of CpBV-CRP1 disappeared, whereas other genes encoded in the CpBV segment was expressed. These co-injected larvae significantly recovered the hemocyte-spreading capacity and larval development rate. This study reports that CpBV-CRP1 is expressed in P. xylostella parasitized by C. plutellae and its physiological function is to alter the host immune and developmental processes.