| Persistence of two insecticides on tomato plants to determine releasing time of Bracon hebetor Say (Hymenoptera: Braconidae) |
| Paper ID : 1288-3IICE (R1) |
| Authors: |
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َAtefeh Khosroabadi *1, Ali Afshari2, Vahid Rahiminejad3 1Gorgan university og Agricultural sciences and natural Resources-faculty of plant production-Department of plant protection 2Department of Plant Protection, faculty of Plant Production, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran 3Department of Plant Protection, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran. |
| Abstract: |
| Abstract Bracon hebetor (Say) (Hymenoptera: Braconidae) is a well known cosmopolitan ectoparasitoid that also attacks larvae of the tomato fruitworm, Helicoverpa armigera (Hübner), the most destructive pest of tomato (Lycopersicon esculentum) in northern Iran. One of the major purposes of Integrated Pest Management (IPM) strategies is to combine the safe and sustainable use of pesticides with biological control agents and using reduced-risk chemicals is a principal tool to reach this goal. The safe time interval between tomato field spraying and B. hebetor releasing is an important question that is often asked by tomato producers. International Organization of Biological Control (IOBC) has recommended a standard method for assessing the duration of harmful activity (persistence) of pesticides against natural enemies and identifying selective pesticides for use in integrated control programs. Therefore, this study was carried out to study the persistence of two insecticides, Proclaim Fit (as a new registered insecticide) and Thiodicarb (as a conventional insecticide) on tomato plants and their residues lethal and sublethal effects on this parasitoid under laboratory conditions (25±1 °C, 65±5% RH, and 16:8 h L: D). Field recommended concentration of these insecticides was sprayed on tomato plants. Then, tomato leaves were removed at one-day intervals and placed within a container with a population (30 individuals) of female B. hebetor. The mortality and fecundity of parasitoid were assessed every day until insecticide toxicity reach to harmless category, according to IOBC standards. Our results showed that, Proclaim Fit was a short-lived (non-persistent) insecticide and its residues on tomato plants caused only 14.1% mortality (harmless category) in parasitoid population one day after treatment. Moreover, Proclaim Fit residues had no sublethal effect on parasitoid fecundity in the first seven days after treatment. In contrast, Thiodicarb was a more persistent insecticide than Proclaim Fit and its mortality and reduction of fecundity reached to harmless category 7 and 14 days after treatment, respectively. In conclusion, B. hebetor can be recommended to release about one day after Proclaim Fit spraying, whereas at least a14-days interval should be considered between thiodicarb spraying and B. hebetor releasing in tomato fields. |
| Keywords: |
| Key words: Bracon hebetor, Insecticides, IOBC, Persistence, Tomato |
| Status : Paper Accepted (Poster Presentation) |
