Targeting pesticide applications

Spray drift is defined for this topic by the National Coalition On Drift Minimization (NCODM) as The physical movement of pesticide through the air at the time of pesticide application or soon thereafter from the target site to any non- or off-target site . Secondary drift, defined by NCDOM as vapor drift or subsequent dust and particle movement after the application , is only partially addressed, although most key principles discussed will still also apply to such secondary movements. 

In Tables 14.9 and 14.10, the last column reports the environmental impact points (EIPs) for typical applications of organic and conventional pesticides derived from the Pesticide Environmental Assessment System, or PEAS. This model produces relative rankings of risks based on defined use rates and use patterns (the formulation used to apply a pesticide, timing, target of the application, spray equipment used, etc). PEAS scores reflect an equal balancing of acute pesticide risks to farm workers, chronic risks via dietary exposure and exposures to birds, Daphnia and bees. 

Deaths of target organisms associated with intentional pesticide applications to insect-infested crops, weed-choked roadsides, and nematode-laced fields are predictable, desirable, and relatively easy to measure. Likewise, catastropic releases of chlorine from ruptured tank cars or of crude oil from scuttled supertankers may produce a spectrum of biological effects including toxicity. These events are easily associated with exposures to toxic substances and particular environmental circumstances. 

One of the major reasons for the interest in insect pheromones is their potential for use to control pests. In one method a large number of traps, baited with small amounts of the sex attractant of the female insect, are used to trap enough males that the breeding of the insects is decreased. In another method that requires fewer traps, a small number of traps are used to monitor the population of the target insect. The best time to apply pesticides can be determined by monitoring these traps. In one case, 10 to 15 applications of a pesticide to control the pink bollworm still resulted in damage to 30% of a cotton crop. This was decreased to almost no damage with only one to two pesticide applications when the ideal times for these applications were determined by the use of traps. 

Wind—Wind speed and direction can greatly alter the effectiveness of a pesticide application. Excessive wind can blow the pesticide off target and resnlt in inadeqnate control. Even moderate winds can greatly alter the coverage of ULV and mist blower applications. Sometimes the applicator can compensate for minor winds by applying the pesticides at an angle where the winds blow the chemical towards the area to be protected. 

Many factors affect the ability to place a pesticide on the target in the manner and amount for most effective results, with the least undesirable side effects, and at the lowest possible cost. Certainly the selection and use of equipment are of utmost importance and deserve major emphasis when considering pesticide application. However, without proper consideration to calibration, formulation, adjuvants, compatibility, and use records, successful appli-... 

Pesticides may harm nontarget organisms that are present during a pesticide application. Poorly timed applications can kill bees and other pollinators that are active in or near the target site. Pesticides may harm other wildlife, too. Even tiny amounts of some pesticides may harm them or destroy their source of food. 

The efficient application of pesticides and other xenobiotics to crops relies on targeting. The optimum use of pesticides requires not only correct timing, but also efficient transfer of active ingredients to those areas within a crop where the pests, weeds or diseases are located. Because a large majority of pesticide applications are made using liquid sprays, this chapter is devoted to the targeting of sprays where the whole field is treated. In a later chapter the selective application of pesticides to areas within a field, or patch spraying , is discussed. 

In order to optimise pesticide application, knowledge of its performance is required. We will examine here some of the fundamental features of pesticide application techniques, so that later we can introduce a systematic approach to targeting and examine how specific applications in specific crops can be targeted. More detail on pesticide application fundamentals is found in Mathews (1992) and Mathews and Hislop (1993). 

Pesticide transport by surface runoff and soil erosion is a function of time lag between rainfall and application the chemical nature and persistence of the pesticide the hydrological, soil, and vegetative characteristics of the field and the method and target of application (43). Wauchope (44) found that unless severe rainfall occurred shortly after pesticide application, total losses for the majority of pesticides due to runoff were less than 0.5% of the amount applied in most cases, although single-event losses from small plots or watersheds can be much greater. 

In addition to the use inconsistent statement, the Directions for Use must enumerate the site or sites of application, e.g., the crops, animals, areas, or objects to be treated by the pesticide, the target pest or pests associated with each site and pest combination. They must also include instructions on methods of applying the pesticide, including, when required, directions on dilution and or... 

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