Applying certain fumigants to which depth can help keep them on target without requiring tarping or water treatment?

The application of fumigants at a depth of 18 to 30 inches is ideal for maintaining effective targeting without the need for tarping or water treatment. This depth strikes a balance between ensuring that the fumigant is adequately contained within the soil and allows for effective gas penetration to control pests.

When fumigants are applied at this depth, they can concentrate the gas closer to the target pest population, while also minimizing the risk of environmental loss or escape into the atmosphere. This depth is also deep enough to protect against potential dispersal from surface activities, allowing for optimized efficiency in pest control.

In contrast, applying fumigants at shallower depths, such as 6 to 12 inches, may lead to higher risks of volatility and loss of efficacy, as the gas could escape more readily. Similarly, deeper applications, such as 30 to 36 inches, may hinder the effectiveness of fumigation because the gas may not reach the target pest population effectively. Therefore, the specified depth of 18 to 30 inches allows for a controlled and efficient application of fumigants.