Texas Pesticide Applicator Practice Exam

What formulation should be chosen if there is a concern about phytotoxicity?

1. Emulsifiable concentrate

2. Granular

3. Wettable powder

4. Fumigant

The correct answer is: Wettable powder

When considering the potential for phytotoxicity, wettable powders are often the formulation of choice. This is primarily because wettable powders generally consist of solid particles that are suspended in water. They tend to have a lower risk of causing harm to plants compared to other formulations, as they allow for more uniform application and can be mixed with a larger volume of water, which dilutes the active ingredient. This dilutive effect minimizes the concentration of pesticide that comes into contact with the plant foliage, thereby reducing the likelihood of damaging sensitive plants. In contrast, emulsifiable concentrates can have a higher potential for phytotoxicity due to their ability to penetrate plant tissues more effectively and rapidly, which can lead to injuries if the plant is susceptible. Granular formulations, while often less likely to cause immediate burn or injury, still pose risks if they come into contact with foliage or are applied near the root zone of sensitive plants. Fumigants, on the other hand, are gaseous and can cause extensive damage if not managed properly, as they disperse quickly and can affect large areas very intensely. Therefore, selecting a wettable powder formulation is a prudent choice in scenarios where the risk of phytotoxicity is a concern, as it strikes a balance between effectiveness and