ISHS Acta Horticulturae 542: VII International Symposium on the Processing Tomato
HIGH-VOLUME APPLICATIONS TO IMPROVE CANOPY PENETRATION AND EFFICACY OF REDUCED RISK INSECTICIDES IN PROCESSING TOMATOES |
| Authors: | E. Cullen, F. Zalom, W. Steinke, N. Hummel |
| Keywords: | Spray volume, nozzle type, droplet distribution, IPM, FQPA |
| Abstract:
The potential for high-volume application of reduced risk insecticides to improve efficacy of these materials in processing tomatoes, Lycopersicon esculentum Miller, was assessed. Restriction and potential cancellation of organophosphate insecticides are anticipated as a result of the 1996 U.S. Food Quality Protection Act (FQPA). Regulatory constraints will mandate reduced-risk control options for tomato insect pests commonly treated with organophosphates, yet reduced-risk insecticides applied at standard volumes have consistently failed to provide effective field control in tomatoes. Lack of canopy coverage is a plausible explanation for poor field control since efficacy of reduced risk materials is dependent upon contact activity with minimal residual effect. Treatments consisted of horticultural mineral oil applications using hollow cone, flat fan, and air assisted hollow cone nozzles at 283, 568, 1,135, and 1,700 L/ha, respectively. Three 5.1 × 7.6 cm2 water-sensitive dye cards per plant, positioned in upper, interior, and soil surface canopy locations, were used to assess canopy coverage by treatment in a completely randomized block design. Water volume was statistically significant for improved canopy coverage at all three card positions, with 1,135–1,700 L/ha providing the best coverage. Nozzle type was significant for improved canopy coverage at upper and interior positions, and marginally significant at the soil surface. Hollow cone nozzles without air assist provided the best coverage at all three card positions. Overall, interactions between water volume and nozzle type were not significant. Results of this study can be used to increase field efficacy of reduced-risk insecticides by improving canopy penetration. This knowledge will allow growers to consider costs and benefits of targeting inner-canopy and soil-level insect pests with high-volume applications. | |
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