Commercial availability of biological control agents.

Abstract.A suitable host provides, at least, the minimum nutritional and physiological conditions for the development of the immature stages of a parasitoid. Host quality may influence the developmental time, mortality rate, longevity and fecundity of parasitoids. This work evaluates the suitability and quality of Aphis gossypii Glover, Brevicoryne brassicae (Linné), Myzus persicae (Sulzer), Rhopalosiphum maidis (Fitch) and Schizaphis graminum (Rondani) as hosts for Aphidius colemani Viereck. Twenty second-instar nymphs of each aphid species were exposed to parasitism for one hour, and then kept in a climatic chamber at 22 ± 1°C, 70 ± 10% RH and a 12 h photophase. The aphid B. brassicae was unsuitable for the development of A. colemani. The different aphid host species varied in size: M. persicae > (R. maidis = S. graminum) > A. gossypii. Parasitoid fitness decreased accordingly when reared on (M. persicae = R. maidis) > S. graminum > A. gossypii. Large hosts seem to be better than small hosts based on parasitoid size. Egg load of A. colemani was related probably more on the ability of the parasitoid larva to obtain nutritional resources from the different host species than on host size.

Section: Introductionmentioning

confidence: 99%

The effect of the quality and size of host aphid species on the biological characteristics of Aphidius colemani (Hymenoptera: Braconidae: Aphidiinae)

Sampaio¹,

Bueno²,

Conti³

2008

“…Its hosts belong to the family Aphididae (Starý, 1975). It is a polyphagous parasitoid, which is widely used in the biological control of Aphis gossypii (Glover) (Homoptera: Aphididae) and Myzus persicae (Sulzer) infesting protected crops (van Schelt et al, 1990;Grasswitz & Reese, 1998;Elenberg et al, 2000;Bolckmans & Tetteroo, 2002;van Lenteren, 2003;Yano, 2006).…”

Section: Introductionmentioning

confidence: 99%

Studies on the identity of the parasitoids Aphidius colemani and Aphidius transcaspicus (Hymenoptera: Braconidae)

Garantonakis¹,

Perdikis²,

Lykouressis³

et al. 2009

Abstract. The taxonomic status of the aphid parasitoid Aphidius colemani Viereck has been questioned, especially in regard to Aphidius transcaspicus Telenga (Hymenoptera: Braconidae). The genetic association between A. colemani and A. transcaspicus was studied by cross mating individuals of A. colemani and A. transcaspicus (A.c.& × A.t.% and A.c.% × A.t.&) and applying appropriate molecular methods. The cross mating resulted in offspring (female and males) that were fertile. Therefore, the cross mating assays performed in an artificial environment showed that these two populations are potentially compatible. The mean number of mummies that developed and the sex ratio of the offspring of each cross were similar. Most of the male and female offspring from each cross were assigned to A. transcaspicus. Furthermore, the genetic divergence between the ribosomal internal transcribed spacers (ITS2) of the A. colemani and A. transcaspicus studied was 16%. These results indicate that A. colemani might be a complex of species with different morphological and biological characters attacking different host aphids.

“…Myzus persicae (Sulzer), and particularly Aphis gossypii Glover (Hemiptera: Aphididae), are suitable hosts for the development and reproduction of this parasitoid (van Steenis, 1993;Sampaio et al, 2008), and it prefers to oviposit in the first-and secondinstar nymphs (Perdikis et al, 2004). Although A. colemani is widely used in the biological control of A. gossypii and M. persicae infesting greenhouse crops (van Lenteren, 2003;Yano, 2006), the factors that influence its host selection are poorly studied (Grasswitz, 1998).…”

Section: Experimental Materialsmentioning

confidence: 99%

Effect of female size on host selection by a koinobiont insect parasitoid (Hymenoptera: Braconidae: Aphidiinae)

Lykouressis¹,

Garantonakis²,

Perdikis³

et al. 2009

Abstract. Body size is a main fitness component of insect parasitoids. We assessed the potential influence of maternal size of the parasitoid wasp Aphidius colemani Viereck (Hymenoptera: Braconidae: Aphidiinae) on its ability to parasitize the different instars of Aphis gossypii Glover (Hemiptera: Aphididae) on eggplant and cucumber. In the experiments "small" vs "large" parasitoid females were used. Females oviposited in all instars but more of the smaller hosts were parasitized. Host selection was affected by female size and the larger hosts were more frequently mummified by the large than the small females. Thus, parasitoid female size influenced host selection. This could affect the potential of the parasitoid to exploit populations of aphids that differ in their size structure. The importance of these results in terms of the ecological adaptations of the parasitoid and their implication for biological control are discussed.