Maximizing Pesticide Application Efficiency Paul Jepson IPPC Oregon State University. OSU Integrated Plant Protection Center

Transcription

1 Maximizing Pesticide Application Efficiency Paul Jepson IPPC Oregon State University OSU Integrated Plant Protection Center

2 Drift happens: waste, risky losses and reduced efficacy

3 PRINTABLE FACT SHEET AVAILABLE AT IPMNET.ORG ENGLISH AND SPANISH VERSIONS AVAILABLE

4 PESTICIDE APPLICATION AND WEATHER CONDITIONS The three kinds of pesticide drift that are caused by the weather 1. Wind drift 2. Thermal drift 3. Inversion Drift

5 WIND DRIFT WIND DIRECTION

6 The risk of wind drift is highest when wind speeds exceed 9mph. The risk of wind drift is greater if sprayers are poorly calibrated or if nozzles are worn. Excessive boom height, and poor boom suspension can also exacerbate drift.

7 AVOIDING WIND DRIFT Spray in wind speeds of 2-9 mph, and when temperatures are less than 70 degrees F. Keep boom height to a minimum, moderate ground speed and moderate tank pressure. Use an unsprayed buffer or offset to protect sensitive sites downwind.

8 THERMAL DRIFT Spray drops evaporate rapidly in warm, dry conditions, and are carried away on convection currents

9 There is a high risk of thermal drift when temperatures exceed 70 degrees F and humidity falls below 40%.

10 AVOIDING THERMAL DRIFT Use weather forecasts and spray in cooler conditions. With air blast sprayers, target the tree, turn off the sprayer at row ends, spray inwards in the outer rows, and moderate ground speed, nozzle flow rate and air speed. Unsprayed crop buffers reduce contamination of sensitive downwind sites.

11 INVERSION DRIFT

12 Inversions cause spray clouds to remain buoyant for long periods. They can move large distances on air currents. Avoid cool, stable conditions with low surface mixing of the atmosphere.

13 AVOIDING INVERSION DRIFT Spray in wind speeds of 2-9 mph so the spray can be carried into the crop canopy. Increase drop size by moderating nozzle pressures and ground speed on marginal days.

14 General Drift Management Guidance Plan ahead (NOW!) to protect sensitive sites Map each field, including areas to be protected Consider climate at the different times you spray (including wind direction) Site buffer zones to intercept possible drift, downwind from sprayed sites Invest in drift reduction technologies (DRT s)

15 Seasonal drift risk There is a high risk of drift occurring when: 1. Wind drift: Wind speeds > 9mph 2. Thermal drift: Temperatures > 70 o F, RH <40% 3. Inversion drift: Stable air, following cool, cloudless nights in spring and fall THE FOLLOWING TABLES ARE BASED ON LONG-TERM AVERAGES AND ARE FOR GUIDANCE ONLY, TO ASSIST DISCUSSIONS ON HOW YOU SHOULD PLAN YOUR APPLICATION AND DRIFT MANAGEMENT PRACTICES IN THE SEASON AHEAD

16 Calendar of LOW risk, CAUTION and HAZARD for wind, thermal and inversion drift, Portland J F M A M J J A S O N D Mean wind speed Low wind drift risk (%<7 mph) Caution (7-11 mph) Hazard (>12 mph) Mean max temp RH 10am RH 4pm Proportion calm

17 Calendar of LOW risk, CAUTION and HAZARD for wind, thermal and inversion drift, Salem J F M A M J J A S O N D Mean wind speed Low wind drift risk (% <7 mph) Caution (7-11 mph) Hazard (11 mph) Mean max temp RH 10am RH 4pm Proportion calm

18 Calendar of LOW risk, CAUTION and HAZARD for wind, thermal and inversion drift, Medford J F M A M J J A S O N D Mean wind speed Low wind drift risk (%<7 mph) Caution (7-11 mph) Hazard (>12 mph) Mean max temp RH 10am est RH 4pm est Proportion calm

19 Calendar of LOW risk, CAUTION and HAZARD for wind, thermal and inversion drift, Pendleton J F M A M J J A S O N D Mean wind speed Low wind drift risk (% <7 mph) Caution (7-11 mph) Hazard (>12 mph) Mean max temp RH 10am RH 4pm Proportion calm

20 General Drift Management Guidance Develop a strategy for responding to marginal and hazardous conditions Use weather forecasts Buy equipment to measure wind speed and direction, air temperature and humidity on spray days Spray less sensitive areas on marginal days, or only spray part of fields that are upwind of sensitive sites Use less hazardous materials, increased drop size, lower ground speed, lower air volume, in parts of field near sensitive sites

21 Annual wind rose for Salem Dominated by southerly winds (about 8% of the time), but winds blow from all directions and can be >7 knots (*red and above on the chart) Is this the year-round pattern?

22 May to July Between May and October, the wind shifts from southerly to omnidirectional, to northerly, and back to southerly August to October For a given field, the designation of sensitive sites downwind could shift by 180 degrees, depending upon the predominant wind direction Buffer zone siting depends upon the times of year when you apply the most hazardous products

23 Obtaining weather forecast data National weather service graphical forecasts: IPPC, weather-based decision support tools:

24 Sprayer adjustments and drift reduction technologies

25 Boom sprayers: nozzle selection NOZZLE CATEGORIES CONVENTIONAL FLAT FAN PRE-ORIFICE LOW-PRESSURE AIR INDUCTION HIGH PRESSURE AIR-INDUCTION COMMENTS Fine spray, reliable, but drift prone 50% drift reduction, reliable at low volumes 50-70% drift reduction 70-90% drift reduction USE GUIDE 20-60psi, >3gpa psi, >5gpa psi, >5gpa psi, >7gpa

26 TeeJet XR 40 psi in 12 mph crosswind Turbo Drop 11003@ 70 psi in 12 mph crosswind

27 Drift management for air-blast sprayers Air-blast sprayers require wider buffers and greater attention to drift mitigation Spray outer rows using nozzles on one side, spraying inwards in small tree and bush crops Increase drop size in outer rows Where spraying from both sides, aim nozzles and air flow at tree, and avoid under and over-spraying, and shut off outward spraying nozzles when treating outer rows Shut off spray at row end and in gaps Reduce ground speed, which reduces air speed necessary for penetration

28 Dormant spraying near Mill Creek Spray emerging above a 20ft high mature tree canopy Photo s by Mike Omeg: htm

29 Maximizing the proportion of applied spray that remains on the tree Increased within-crop efficiency Spray when wind is >3mph, <9mph; temp. >10F, <70F; >40%RH Adjust nozzles to target tree Moderate air volume Moderate ground speed Larger drop size (mid pressure, volume range for nozzle) Sensor-equipped sprayer Reduced off-crop losses Vegetated buffer strip 6m crop-free zone Inward spraying, outer 6 rows Particular caution for dormant sprays IPM adoption

30 Air-blast sprayer with air induction nozzles

31 Deposition (ul/cm2) Spray Deposition (ul/cm2) Air-Induction Nozzles on Airblast Airblast No Donut Air-Induction Nozzles on Airblast Airblast No Donut B 15M 15T 30B 30M 30T 50B 50M 50T Distance from spray swath (m) and sampling height 0 1L 2L 3L 4L 5L 6L 7L 8L Row Number and 1m Sampling Height Drift potential of airinduction and hydraulic cone nozzles. Spray coverage from air-induction and hydraulic cone nozzles.

32 Conclusions Drift management is achievable with all sprayer types Coverage with DST s vary strikingly and efficacy studies are required to understand impacts on biological effects Multi-row penetration from air-blast sprayers requires further work: Are doses elevated excessively, particularly downwind, after several passes? Are upwind rows at edge of orchard under-sprayed?

33 uspest.org/wea Website home page

34 USPEST.ORG/WEA constantly updating features: e.g. click in degree-day map to get clock report Clock report click

35 MyPest Page: 98 models, 15K+ weather stations

36 Pesticide risk assessment as a component of maximizing efficiency

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38 Pesticide Application Information

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42 Typical examples from individual farm programs INDEX Rye g. Orch g. Brocc. Bean Grape Hazel Inhalation Aq. invert Aq. algae Fish chr. Earthw. Small mam. Avian repr. Avian Ac. LOW, INTERMEDIATE, HIGH RISK Responses vary by crop, pesticide, index Risk reduction and mitigation options include IPM, substitution, reduced use, BMP s, buffers, offsets, spray technology

43 IF YOU PLAN AHEAD, SPRAYS CAN BE SCHEDULED FOR MAXIMUM IMPACT AND THE RISK OF PESTICIDE LOSS CAN BE REDUCED WITH BENEFITS FOR PEST CONTROL EFFICIENCY, COST SAVING, THE ENVIRONMENT AND HUMAN HEALTH OSU Integrated Plant Protection Center