Operation of Hand Sprayers
Although most hand sprayers are limited to small plantings, the handgun can supply a high application rate because the pump is powered and the spray mix is portable. Be sure, however, to practice with water while gaining application competence.
Hand sprayers place the operator near the nozzles and discharge point of the sprayer. Therefore, all operators should wear a hat, a long-sleeve shirt, and trousers, or a spray suit. Depending on the toxicity of the chemical, other protective wear such as a respirator, goggles, waterproof gloves, and waterproof boots might be required. The spray should be discharged when there is little or no wind, so drift is minimized and the chemical is not blown on the operator. Always follow the instructions on the pesticide label attached to the container.
Drift from a hand sprayer can be dangerous, especially when the spray mix is concentrated. The best solution is to spray only when winds are less than 5 mph, which is a very mild breeze. Operators should also use as low a pressure and as large a nozzle orifice as is practical to minimize the number of small droplets. Herbicides should be applied at 15 to 40 psi, depending on nozzle design. A drift control agent added to the spray mix might also help.
Thoroughly spraying the entire plant is necessary for satisfactory pest control. Amounts of spray material per plant for various fruits are listed in Table 2.3. Pesticide suggestions are based on the need for pest control under average conditions. Applying reduced amounts of pesticide is practical under relatively ideal conditions, which include using highly effective chemicals and efficient sprayers, as well as having a fruit planting with no special pest problems. Conditions can change rapidly, especially during periods of unusually moist weather. The fruit grower must be prepared to adjust the amount and frequency of pesticide applications to handle such situations in accordance with label limitations.
Pesticides have specific ranges of activity. In other words, a particular insecticide might kill one type of insect but not another type. Some insecticides have a very broad spectrum of activity, killing a wide variety of pests. Other insecticides have a narrow spectrum, killing only a few kinds of pests.
Knowledge of the properties of insecticides is just as important as knowledge of the biology of the pest. In addition, some insecticides might be harmful to the plant in some situations. An insecticide that successfully controls insects on apples might cause all of the leaves to fall off a raspberry plant. It pays to read the label on the pesticide container and pay attention to the recommendations, cautions, and warnings in this guide to avoid disastrous results from the misuse of pesticides.