Which option lists a factor NOT listed as a potential cause of white grub control failure?

• A. Lack of sufficient post-treatment irrigation
• B. Drought conditions
• C. Over-irrigation
• D. Too much thatch

Answer: (B)

The key idea is that grub-control success depends on getting the active ingredient into the soil where the grubs feed and keeping it there long enough to work. After you apply a product, some form of irrigation is needed to move it into the root zone. If you don’t provide enough post-treatment irrigation, the chemical stays on the surface and won’t contact many grubs, leading to poor control. Conversely, too much irrigation can wash the product away or push it past where the grubs are feeding, reducing effectiveness. Excessively thick thatch creates a barrier that slows or blocks the product from reaching the soil and reaching the grubs. Drought conditions, while they affect turf health, aren’t typically cited as a direct cause of grub-control failure in these guidelines, so they’re not considered a factor in the listed reasons for reduced efficacy.