caa a22 4500 606161465 CHVBK 20210128100634.0 cr unu---uuuuu 210128e20151201xx s 000 0 eng 10.1007/s10526-015-9685-0 doi (NATIONALLICENCE)springer-10.1007/s10526-015-9685-0 Hot-spot application of biocontrol agents to replace pesticides in large scale commercial rose farms in Kenya [Elektronische Daten] [Catherine Gacheri, Thomas Kigen, Lene Sigsgaard] Rose (Rosa hybrida L.) is the most important ornamental crop in Kenya, with huge investments in pest management. We provide the first full-scale, replicated experiment comparing cost and yield of conventional two-spotted spider mite (Tetranychus urticae Koch) control with hot-spot applications of the predatory mite Phytoseiulus persimilis (Acari: Phytoseidae) in large commercial rose greenhouses. Hot-spot treatments replaced acaricides except at high infestations and the two treatments were applied in seven greenhouses each. With the conventional treatment, acaricides were applied when T. urticae populations exceeded 250 motile individuals per plant based on scouting. Treatments with acaricides and P. persimilis were guided by weekly scouting and hot-spot treated greenhouses with infestations exceeding 1000 individualsm−2 (calculated as average mites/leaflet×average leaflets per plant) were first blanket-treated with an acaricide to decrease infestations. Roses subjected to the hot-spot treatment had significantly lower T. urticae infestations compared with conventionally treated roses. In addition, significantly fewer high spider mite infestations were recorded in roses with the hot-spot treatment. The cost of pest management was significantly lower in the hot-spot-treated greenhouses than in the conventional treatment. However, there was no significant difference in the number of harvested stems from the two treatments. It can therefore be concluded that acaricides can be replaced by P. persimilis hot-spot treatments in commercial cut rose production, effectively reducing pest management costs with no loss in crop yield. International Organization for Biological Control (IOBC), 2015 Acari nationallicence Phytoseidae nationallicence Cost-benefit nationallicence Rose nationallicence Phytoseiulus persimilis nationallicence Tetranychus urticae nationallicence Gacheri Catherine Dudutech -A Division of Finlays Horticulture Kenya Limited, Kingfisher Farm, P.O. Box 1927, 20117, Naivasha, Kenya aut Kigen Thomas Dudutech -A Division of Finlays Horticulture Kenya Limited, Kingfisher Farm, P.O. Box 1927, 20117, Naivasha, Kenya aut Sigsgaard Lene Department of Plant and Environmental Sciences, Faculty of Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871, Frederiksberg, Denmark aut BioControl Springer Netherlands 60/6(2015-12-01), 795-803 1386-6141 60:6<795 2015 60 10526 https://doi.org/10.1007/s10526-015-9685-0 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s10526-015-9685-0 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Gacheri Catherine Dudutech -A Division of Finlays Horticulture Kenya Limited, Kingfisher Farm, P.O. Box 1927, 20117, Naivasha, Kenya aut NATIONALLICENCE 700 1- Kigen Thomas Dudutech -A Division of Finlays Horticulture Kenya Limited, Kingfisher Farm, P.O. Box 1927, 20117, Naivasha, Kenya aut NATIONALLICENCE 700 1- Sigsgaard Lene Department of Plant and Environmental Sciences, Faculty of Sciences, University of Copenhagen, Thorvaldsensvej 40, 1871, Frederiksberg, Denmark aut NATIONALLICENCE 773 0- BioControl Springer Netherlands 60/6(2015-12-01), 795-803 1386-6141 60:6<795 2015 60 10526