Aphelinid parasitoids as sustainable biological control agents in greenhouses

Abstract

Aphelinid parasitoids have been used for control of pests in greenhouses since the 192Os, but large scale application started only some 25 years ago. Today, several aphelinid parasitoids are commercially used for the biological control of scale, aphid and whitefly pests in greenhouses. A success story is the biological control of greenhouse whitefly, Triulrurodes cuporuriorum, with the aphelinid Encursiu formom. Encursiu is applied on 5000 ha of vegetable crops worldwide. Weekly, more than 20 million individuals of E. jortnosu are mass reared and shipped to growers in 20 countries. About 10 years ago, another whitefly species, Bemisiu sp., developed to pest status and a search for control of scales and aphids in greenhouses is summarized, as well as the status of commercial biological control with aphelinid parasitoids. Further, the questions whether effective natural enemies can be identified before introduction and if autoparasitoids should be imported and released are addressed. Finally, the usefulness of parasitoid biotype studies to recognize suitable candidates for biological is considered.

Life-history parameters of Encarsia formosa, Eretmocerus eremicus and E. mundus, aphelinid parasitoids of Bemisia argentifolii (Hemiptera: Aleyrodidae)

“…This indicates an intrinsic or even heritable difference between the strains. Heritable differences have been found between these two strains in their host acceptance, host handling behaviour, immature development, immature survival and rate of parasitism (van Lenteren et al, 1997;. A large difference in the life-spans of the two E. formosa strains was found when hosts were present.…”

“…Our research group has for the past 25 years been working on the biological control of greenhouse pests, initially mainly on parastioids of greenhouse whitefly (Trialeurodes vaporariorum (Westwood), van and during the past 15 years also on parasitoids of Bemisia (van Lenteren et al, 1997;Drost et al, 2000). For B. tabaci, Gerling et al (2001) list 34 species of Encarsia, 12 species of Eretmocerus, one species of Signiphora and Methycus, and two Amitus species.…”

“…However, B. argentifolii is a less favourable host for the E. formosa strain that is mass produced in the Netherlands, and control with E. formosa in greenhouses is not successful at high release rates of 4-7 adult females per plant per week in North America (Hoddle & van Driesche, 1996). As a strain of E. formosa collected in Maryland, USA (the so called Beltsville strain) was considered to be a more promising agent for B. argentifolii control, according to laboratory and greenhouse evaluation (Heinz & Parrella, 1994;van Lenteren & Brasch, 1994;Hoddle et al, 1997;van Lenteren et al, 1997), it was included in the current study, together with the Dutch E. formosa strain for comparison. Field studies showed that in North America Eretmocerus species are the most abundant parasitoids (Goolsby et al, 1998) of B. argentifoliii.…”

Conservation and evaluation of natural enemies in IPM systems for Bemisia tabaci

“…The progress of these efforts have been primarily reported through published abstracts of symposia, conferences, and workshops (Naranjo et al, 2000). Efforts in augmentation have primarily focused on protected agricultural systems (e.g., van Lenteren et al, 1997;Hoddle et al, 1998;Gerling et al, 2001), although some research has examined the potential utility and efficacy of augmentation in field crops (e.g., Heinz et al, 1999;Simmons and Minkenberg, 1994;Joyce and Bellows, 2000). Biological control with parasitoids has received the most attention, followed by use of arthropod predators and fungal pathogens.…”

Selection of Bemisia nymphal stages for oviposition or feeding, and host-handling times of arrhenotokous and thelytokous Eretmocerus mundus and arrhenotokous E. eremicus

“…To date, several species of parasitoids are used with great success to control whitefly in large commercial greenhouses . The most efficient species belong to the aphelinid genera Encarsia, Eretmocerus and the Platygasterid genus Amitus (van Lenteren et al, 1997;Drost et al, 1999Drost et al, , 2000Manzano et al, 2000Manzano et al, , 2002de Vis et al, 2003;Qiu et al, 2004). Gerling et al (2001) list 34 species of Encarsia, 12 species of Eretmocerus, two species of Amitus, and one species each of Signiphora and Methycus as parasitoids of Bemisia tabaci (Gennadius) (Hom; Aleyrodidae), which is the most serious whitefly pest of vegetable, ornamental, and agronomic crops throughout the world (Gerling, 1990;Gerling and Mayer, 1995).…”