Parasitism, host feeding and immature development of Encarsia formosa
 reared from Trialeurodes vaporariorum
 and Bemisia tabaci
 on Trialeurodes ricini

It is not unusual for parasite attack on insect hosts to have different consequences for individuals of the same species. An indication of the variation in types of alternative effects is given by a consideration of three host-parasite relationships. First, although most hosts in a population are susceptible to parasitization, some are immune to attack: about one in 3,000 larvae of the Mediterranean flour moth, Anagasta kühniella (Zeller), was found by Payne (1934) to be immune to attack by Bracon hebetor Say. Second, tile morphology of hosts may be modified differentially by parasitism: unhatched eggs of Aphdius platensis Brethes exert a juvenilizing effect on nymphs of Aphis craccivora Koch whereas parasite larvae sometimes cause the appearance of adult characters (Johnson, 1959). Third, some hosts are successfully parasitized whereas others are killed long before parasite progeny can mature: adult females of Metaphycus helvolus (Com.) kill the black scale, Saissetin oleae (Bern.), by parasitization, by mutilation with the ovipositor, and by host-feeding at wounds made by the ovipositor. Field tests showed that up to 97 per cent of a black-scale infestation may be killed by the parasite over a period of several months.

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The suitability of biotypes Q and B ofBemisia tabaci(Gennadius) (Hemiptera: Aleyrodidae) at different nymphal instars as hosts forEncarsia formosaGahan (Hymenoptera: Aphelinidae)

PeerJ ◽

10.7717/peerj.1863 ◽

2016 ◽

Vol 4 ◽

pp. e1863 ◽

Cited By ~ 7

Author(s):

Xin Liu ◽

Youjun Zhang ◽

Wen Xie ◽

Qingjun Wu ◽

Shaoli Wang

Keyword(s):

Biological Control ◽

Feeding Rate ◽

Trialeurodes Vaporariorum ◽

Host Feeding ◽

Encarsia Formosa ◽

Greenhouse Crops ◽

Commercial Strain ◽

Promising Tool ◽

Adult Parasitoid ◽

Biotype B

Encarsia formosaGahan (Hymenoptera: Aphelinidae) is a solitary endoparasitoid that is commercially reared and released for augmentative biological control of whiteflies infesting greenhouse crops. In most areas in China, the invasive and destructive whiteflyBemisia tabaci(Gennadius) (Hemiptera: Aleyrodidae) biotype Q has replacedB. tabacibiotype B and has become dominant between the two. A better understanding of the suitability of different nymphal instars ofB. tabacibiotypes Q and B as hosts forE. formosais needed to improve the use of this parasitoid for biological control. Parasitism of the four nymphal instars ofB. tabacibiotypes Q and B by the commercial strain ofE. formosamass reared onTrialeurodes vaporariorum(Westwood) (Hemiptera: Aleyrodidae) was assessed in the laboratory. The results indicated thatE. formosaparasitized and successfully developed on all instars of both biotypes but performed best on the 3rd instar ofB. tabacibiotype B and on the 2nd, 3rd, and 4th instars ofB. tabacibiotype Q. The host-feeding rate of the adult parasitoid was generally higher on nymphal instars ofB. tabacibiotype Q than on the corresponding nymphal instars of biotype B and was significantly higher on the 2nd and 3rd instars. For both whitefly biotypes, the parasitoid’s immature developmental period was the longest on the 1st instar, intermediate on the 2nd and 3rd instars, and the shortest on the 4th instar. The parasitoid emergence rate was significantly lower on the 1st instar than on the other three instars and did not significantly differ betweenB. tabacibiotype B and biotype Q. Offspring longevity was greater on the 3rd and 4th instars than on the 1st instar and did not significantly differ between the twoB. tabacibiotypes. The results indicate that commercially-producedE. formosacan parasitize all instars ofB. tabacibiotypes B and Q, making this parasitoid a promising tool for the management of the two biotypes ofB. tabacipresent in China.

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Molecular divergence of secondary endosymbiont, Cardinium in Bemisia tabaci (Gennadius) and associates

Bangladesh Journal of Agricultural Research ◽

10.3329/bjar.v40i1.23765 ◽

2015 ◽

Vol 40 (1) ◽

pp. 121-135 ◽

Cited By ~ 1

Author(s):

SMH Jahan ◽

KY Lee ◽

MIA Howlader ◽

HMK Bashar ◽

GN Hasan

Keyword(s):

Bemisia Tabaci ◽

Trialeurodes Vaporariorum ◽

The Philippines ◽

Encarsia Formosa ◽

Phylogenetic Groups ◽

Rdna Sequences ◽

Aleurodicus Dispersus ◽

16S Rdna Sequences ◽

Q Biotype ◽

Secondary Endosymbiont

Whitefly, Bemisia tabaci (Hemiptera : Aleyrodidae) harbors numerous secondary endosymbionts, which are transmitted from mother to offspring by both horizontally and vertically, that have crucial role on host selection, biology, and evolution. Bacteria, Cardinium was identified in B. tabaci as well as in other whitefly population from many different countries by comparing 16S rDNA sequences. Cardinium were detected in all tested indigenous B. tabaci populations of Bangladesh, Myanmar, Nepal, and the Philippines as well as Q1 biotype of Korea. It was absent in B biotype of Korea and Q biotype of China. Cardinium was also detected in three out of five tested Aleurodicus dispersus population as well as in five out of seven Trialeurodes vaporariorum, whereas they were not detected in Tetraleurodes acaciae populatuion. In adition, Cardinium was detected in parasitoid Encarsia formosa attacking B. tabaci. Among the 19 whitefly populations from different countries, present studies identified four phylogenetic groups of Cardinium, thereby demonstrating the high diversity of this genus. Cardinium phylogeny suggests a correlation of geographical range with ecological variation at the species level.Bangladesh J. Agril. Res. 40(1): 121-135, March 2015

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