TY - JOUR

T1 - The edaphic phase in the ontogenesis of Frankliniella occidentalis and comparison of Hypoaspis miles and Plypoaspis aculeifer as predators of soil-dwelling thrips stages

AU - Berndt, Oliver

AU - Meyhöfer, Rainer

AU - Poehling, Hans Michael

N1 - Funding information: The German Science Foundation (Deutsche Forschungs Gemeinschaft) supported this research. We thank M. Langhof, M. Baalmann, and S. Schiele for technical help in rearing and maintaining cultures.

PY - 2003/10/23

Y1 - 2003/10/23

N2 - The life cycle of the western flower thrips (WFT), Frankliniella occidentalis Pergande (Thysanoptera: Thripidae), comprises an edaphic phase, which offers the opportunity to control this serious pest by the exploitation of soil-dwelling natural enemies. In the present study, the effect of the two soil-dwelling predatory mites, Hypoaspis miles (Berlese) and H. aculeifer (Canestrini) (Acari: Laelapidae), on the population development of the WFT feeding on French beans (Phaseolus vulgaris) was examined. The experiments were carried out in acrylglass tubes, which served as microcosms. The extent of the edaphic phase within a given population of synchronized WFT was investigated by the use of photo-eclectors (emergence traps). This method ensured (1) an easy determination of the proportion of a thrips population entering the soil for pupation and (2) the quantification of the efficiency of predatory mites on the thrips developmental stages in the soil. The results showed that 98% of the thrips population left the bean plant for pupation in the soil. The introduction of five predatory mites caused thrips mortality of at least 44.9%. Doubling the predator density to 10 H. miles increased thrips mortality to 61%. A maximum thrips mortality of 80.5% was attained by the introduction of 20 H. aculeifer. As a result, H. aculeifer showed a greater efficiency as a natural enemy against soil-dwelling developmental stages of the WFT. Both species can be important antagonists of the WFT in protected crops. Opportunities to enhance biocontrol efforts are discussed.

AB - The life cycle of the western flower thrips (WFT), Frankliniella occidentalis Pergande (Thysanoptera: Thripidae), comprises an edaphic phase, which offers the opportunity to control this serious pest by the exploitation of soil-dwelling natural enemies. In the present study, the effect of the two soil-dwelling predatory mites, Hypoaspis miles (Berlese) and H. aculeifer (Canestrini) (Acari: Laelapidae), on the population development of the WFT feeding on French beans (Phaseolus vulgaris) was examined. The experiments were carried out in acrylglass tubes, which served as microcosms. The extent of the edaphic phase within a given population of synchronized WFT was investigated by the use of photo-eclectors (emergence traps). This method ensured (1) an easy determination of the proportion of a thrips population entering the soil for pupation and (2) the quantification of the efficiency of predatory mites on the thrips developmental stages in the soil. The results showed that 98% of the thrips population left the bean plant for pupation in the soil. The introduction of five predatory mites caused thrips mortality of at least 44.9%. Doubling the predator density to 10 H. miles increased thrips mortality to 61%. A maximum thrips mortality of 80.5% was attained by the introduction of 20 H. aculeifer. As a result, H. aculeifer showed a greater efficiency as a natural enemy against soil-dwelling developmental stages of the WFT. Both species can be important antagonists of the WFT in protected crops. Opportunities to enhance biocontrol efforts are discussed.

KW - Acari

KW - Biological control

KW - Edaphic phase

KW - Frankliniella occidentalis

KW - Ground foraging

KW - Hypoaspis aculeifer

KW - Hypoaspis miles

KW - Laelapidae

KW - Microcosm

KW - Phaseolus vulgaris

KW - Predator efficiency

KW - Predatory mite

KW - Thripidae

KW - Thysanoptera

KW - Western flower thrips

UR - http://www.scopus.com/inward/record.url?scp=11144357915&partnerID=8YFLogxK

U2 - 10.1016/j.biocontrol.2003.09.009

DO - 10.1016/j.biocontrol.2003.09.009

M3 - Article

AN - SCOPUS:11144357915

VL - 30

SP - 17

EP - 24

JO - Biological control

JF - Biological control

SN - 1049-9644

IS - 1

ER -