Lack of intraspecific biological variation between two geographical populations of Oomyzus sokolowskii (Hymenoptera: Eulophidae), a gregarious larval–pupal parasitioid of Plutella xylostella (Lepidoptera: Plutellidae)

2004 ◽  
Vol 94 (2) ◽  
pp. 169-177 ◽  
Author(s):  
A.R. Mahmood ◽  
S.S. Liu ◽  
Z.H. Shi ◽  
X.H. Song ◽  
M.P. Zalucki

AbstractThe chalcid, Oomyzus sokolowskii Kurdjumov has been recorded in many parts of the world as a major larval–pupal, gregarious endoparasitoid of the diamondback moth, Plutella xylostella (Linnaeus), a serious pest of brassica vegetable crops worldwide. This study investigated intraspecific variation between two populations of O. sokiolowskii, one from Cape Verde Islands, West Africa and the other from Hangzhou, China. In all crosses and backcrosses between the two geographical populations, the numbers of progeny and sex ratio of progeny were similar to those obtained within each of the populations, demonstrating complete reproductive compatibility between the two populations. The two populations showed similar responses to temperature with respect to development time and survival of immature stages. Observations on the interactions between the two O. sokolowskii populations and Cotesia plutellae (Kurdjumov), another major parasitoid of P. xylostella, showed that neither population could achieve successful parasitism of P. xylostella larvae already parasitized by C. plutellae. However, both O. sokolowskii populations could achieve hyperparasitism by ovipositing into a mid-late stage larva of C. plutellae developing inside the primary host. Contrary to earlier reports, no evidence of intraspecific variations in ability to hyperparasitize between these two populations of O. sokolowskii was found.

2000 ◽  
Vol 90 (3) ◽  
pp. 221-231 ◽  
Author(s):  
Shu-Sheng Liu ◽  
Xin-Geng Wang ◽  
Shi-Jian Guo ◽  
Jun-Hua He ◽  
Zu-Hua Shi

AbstractAn 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 collariswas recorded from April to July and October. Rates of parasitism of P. xylostellain 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.


2021 ◽  
Vol 21 (1) ◽  
pp. 34-42
Author(s):  
Djoko Prijono ◽  
Maya Anggraini ◽  
Sri Riski Maryani ◽  
Eliana Diana Surya

Insecticidal joint action of ternary extract mixtures of four species of tropical plants against Plutella xylostella andCrocidolomia pavonana. The diamondback moth (DBM), Plutella xylostella, and the cabbage head caterpillar (CHC),Crocidolomia pavonana, were two main pests of cruciferous vegetable crops. Among the viable alternative ingredients thatcould be utilized to control those two pests were eco-friendly botanical insecticides. This study was conducted to evaluatethe joint action of ternary extract mixtures of four tropical plant species, i.e. Piper aduncum (Pa), Piper retrofractum (Pr),Sapindus rarak (Sr), and Tephrosia vogelii (Tv), against DBM and CHC. Results of leaf-residue feeding bioassays showedthat based on co-toxicity ratio at both LC 50 and LC levels, ternary mixtures of Pa extract with Sr and Tv extracts at concentrationratios of 1:5:1, 1:5:2, and 2:5:1 indicated synergistic joint action on DBM larvae. A mixture of Pa, Sr and Tv extracts at a ratio of2:5:1 was also synergistic to CHC at both LC level but antagonistic at the LC 95 50 95 and LC 95 levels. This mixture at the 1:5:1 ratio was synergistic on CHC at the LC level whereas at the 1:5:2 ratio was antagonistic to CHC at both LC levels. Furthermore, ternary mixtures of Pr extract with Sr and Tv extracts at the three concentration ratios were synergistic to CHC. Thus, ternary mixtures of Pa or Pr extract with Sr and Tv extracts at appropriate concentration ratios are potential alternatives for the control of DBM and CHC.


2007 ◽  
Vol 10 (2) ◽  
pp. 121-129 ◽  
Author(s):  
Seungbaeck Song ◽  
Jae Young Choi ◽  
Yeon Ho Je ◽  
Yonggyun Kim

2021 ◽  
Author(s):  
Rana M. Sarfraz

Abstract The diamondback moth (DBM) is one of the most studied insect pests in the world, yet it is among the 'leaders' of the most difficult pests to control. It was the first crop insect reported to develop resistance to microbial Bacillus thuringiensis insecticides, and has shown resistance to almost every insecticide, including the most recent groups such as diamide. DBM is a highly invasive species. It may have its origin in Europe, South Africa or East Asia, but is now present wherever its cruciferous hosts exist and is considered to be the most universally distributed Lepidoptera. It is highly migratory and wind-borne adults can travel long distances to invade crops in other regions, countries and continents. Immature stages also hitchhike on plant parts and can establish in new areas. DBM costs the global economy an estimated US$4 -5 billion annually, but its impacts on local biodiversity and habitats in exotic ranges are unknown.


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