Which is the most important cultural method that decreases the Heterodera avenae population?

✅Explanation:
Crop rotation is the most effective cultural method for reducing Heterodera avenae (cereal cyst nematode) populations. This nematode has a narrow host range, primarily infecting cereal crops like wheat and barley. By rotating with non-host crops such as legumes, oilseeds, or vegetables, the nematode population is deprived of its primary food source and its numbers decline significantly.