Seasonal abundance of the parasitoid complex associated with the diamondback moth, Plutella xylostella (Lepidoptera: Plutellidae) in Hangzhou, China

Abstract

An investigation of insect parasitoids of the diamondback moth, Plutella xylostella (Linnaeus), in brassica vegetable crops in the suburbs of Hangzhou was conducted during five periods from 1989 to 1997. Eight species of primary parasitoids were recorded: Trichogramma chilonis Ishii, Cotesia plutellae Kurdjumov, Microplitis sp., Oomyzus sokolowskii Kurdjumov, Diadromus collaris (Gravenhorst), Itoplectis naranyae (Ashmead), Exochus sp. and Brachymeria excarinata Gahan. Seven species of hyperparasitoids were also collected. Rates of parasitism of eggs of P. xylostella were usually very low. However, rates of parasitism of larvae and pupae were substantial and showed two peaks each year, around June-July and September-November respectively. Rates of parasitism during peaks were usually 10-60% and reached over 80% on a few occasions. Cotesia plutellae, O. sokolowskii and D. collaris were the major larval, larval-pupal and pupal parasitoids respectively. In the field, C. plutellae was active throughout the year. Oomyzus sokolowskii was active from May to October, entered a quiescent pupal stage in October-November to overwinter and did not emerge until next April-May. Diadromus collaris was recorded from April to July and October. Rates of parasitism of P. xylostella in radish and mustard fields were usually higher than those in cabbage and Chinese cabbage fields in the same locality. Negative correlations of parasitism rates between C. plutellae and O. sokolowskii indicate a competitive relationship for host larvae between these two larval parasitoids.

Trichogramma chilonis Ishii: A potential biological control agent of Crocidolomia pavonana in Samoa

“…Trichogramma chilonis has been recorded from a wide range of Lepidoptera hosts worldwide (Table 2) and in the Asia-Pacific region it has been recorded in China (Liu et al, 2000), Fiji (Hinckley, 1964), Guam (Nafus, 1993), Hawaii , Indonesia (Herlinda, 2005), Japan (Ishii, 1941), New Caledonia (Cochereau, 1977), Palau (Doutt, 1955), Papua New Guinea (Saucke et al, 2000), Philippines (Litsinger et al, 2007) and Taiwan (Nagarkatti and Nagaraja, 1971). However, significant taxonomic uncertainty surrounds many species within the genus Trichogramma (Noyes et al, 2000) and it is generally accepted that many of the records published before 1970 are unreliable (Polaszek, 2010;Noyes, 2013).…”

Spatiotemporal distribution and impact of diamondback moth parasitoids in the Dakar Niayes in Senegal

“…During this period, climate was favorable for this species whose optimum development occurs at 25 °C and low humidity (Sow et al, 2013a). Brachymeria sp the DBM pupal parasitoid identified in this study, is a facultative generalist hyperparasitoid attacking hymenopteran (Liu et al, 2000). This insect had a low parasitism rate during all seasons, whatever the agro-ecological areas and the sampling year, with the exception of the 2013 cold dry season when its parasitism rate reached 20%.…”

“…Additionally, this species attacks all DBM larval stages (Sow et al, 2013b), resulting in high efficacy during the host larval cycle duration. However, O. sokolowskii can be a facultative hyperparasitoid of C. vestalis (Liu et al, 2000) and therefore harm to the population development of this latter species which were very low during the two cold dry seasons.…”

Exigências térmicas e estimativa do número de gerações de Oomyzus sokolowskii (Kurdjumov) (Hymenoptera: Eulophidae), para regiões produtoras de crucíferas em Pernambuco

“…Por ser uma cultura explorada comumente por pequenos agricultores, o controle biológico, quer seja realizado com o uso de fungos entomopatogênicos (Vandenberg et al 1998), de predadores (Cordero & Cave 1992) ou de parasitóides (Cardona et al 1996, Liu et al 2000, pode ser uma alternativa que se for eficientemente adotada, contribuirá para a manutenção de cultivos de crucíferas satisfatoriamente produtivos, com o mínimo de efeitos indesejáveis ao homem e ao ambiente. Dentre os agentes de controle, o parasitóide Oomyzus sokolowskii (Kurdjumov) tem sido estudado e utilizado em programas de controle biológico em diferentes regiões produtoras de repolho no mundo (Ooi 1988, Mushtaque 1990, Wang et al1999.…”