TY - JOUR

T1 - Performance of two Trichogramma brassicae strains under greenhouse and field conditions for biocontrol of the silver Y moth in spinach cultures

AU - Klug, Thomas

AU - Meyhöfer, Rainer

N1 - Funding information: Acknowledgments The authors thank BBA Darmstadt and AMW-Nützlinge GmbH for recommendations and provision of the two Trichogramma strains and Trichoballs®. Katrin Schildknecht and Jür-gen WiethoV assisted during laboratory and Weld work. The research was funded by Unilever Deutschland GmbH. All Weld experiments were conducted on spinach Welds of contract growers of the company Iglo-Langnese.

PY - 2009

Y1 - 2009

N2 - The suitability of Trichogramma brassicae Bezd. (Hymenoptera: Trichogrammatidae) to control the silver Y moth, Autographa gamma (L.) (Lepidoptera: Noctuidae) in spinach was investigated under greenhouse and field conditions. Two strains of T. brassicae were selected to study host searching efficiency and dispersal ability of the wasps on spinach. The experiments were conducted with defined release densities. The results show that T. brassicae strain I failed to locate host eggs in all experiments. In contrast, T. brassicae strain II females were able to locate 37% of the exposed egg clusters in the greenhouse within 48 h. Individuals colonised rapidly at least an area of 0.25 m2. At distances up to 26 cm to the release point of the T. brassicae females, parasitization rate was 100%. Moreover, under field conditions silver Y moth eggs were exposed two times for 48 h on 12 experimental plots of 100 m2 in two spinach fields. During the first exposure interval, i.e. 4 days after mass release of T. brassicae strain II, overall parasitization rates reached 20% on both fields. Furthermore parasitization rates still reached 16 and 19% during the second exposure interval, i.e. 9 days after natural enemy release, indicating a constant Trichogramma activity over time. Parasitization rates were highest in the close vicinity of the release point, i.e. 86%, whereas 6.5 m away the mean parasitization rate decreased to 3%. In conclusion results indicate a high potential of T. brassicae strain II as antagonist of A. gamma . Nevertheless the dispersal ability of T. brassicae strain II was limited, but adjustment of release densities and techniques might compensate this disadvantage.

AB - The suitability of Trichogramma brassicae Bezd. (Hymenoptera: Trichogrammatidae) to control the silver Y moth, Autographa gamma (L.) (Lepidoptera: Noctuidae) in spinach was investigated under greenhouse and field conditions. Two strains of T. brassicae were selected to study host searching efficiency and dispersal ability of the wasps on spinach. The experiments were conducted with defined release densities. The results show that T. brassicae strain I failed to locate host eggs in all experiments. In contrast, T. brassicae strain II females were able to locate 37% of the exposed egg clusters in the greenhouse within 48 h. Individuals colonised rapidly at least an area of 0.25 m2. At distances up to 26 cm to the release point of the T. brassicae females, parasitization rate was 100%. Moreover, under field conditions silver Y moth eggs were exposed two times for 48 h on 12 experimental plots of 100 m2 in two spinach fields. During the first exposure interval, i.e. 4 days after mass release of T. brassicae strain II, overall parasitization rates reached 20% on both fields. Furthermore parasitization rates still reached 16 and 19% during the second exposure interval, i.e. 9 days after natural enemy release, indicating a constant Trichogramma activity over time. Parasitization rates were highest in the close vicinity of the release point, i.e. 86%, whereas 6.5 m away the mean parasitization rate decreased to 3%. In conclusion results indicate a high potential of T. brassicae strain II as antagonist of A. gamma . Nevertheless the dispersal ability of T. brassicae strain II was limited, but adjustment of release densities and techniques might compensate this disadvantage.

KW - Autographa gamma

KW - Biologicalcontrol

KW - Massrelease

KW - Spinach

KW - Trichogramma brassicae

UR - http://www.scopus.com/inward/record.url?scp=59349086352&partnerID=8YFLogxK

U2 - 10.1007/s10340-008-0224-y

DO - 10.1007/s10340-008-0224-y

M3 - Article

AN - SCOPUS:59349086352

VL - 82

SP - 73

EP - 79

JO - Journal of pest science

JF - Journal of pest science

SN - 1612-4758

IS - 1

ER -