Studies on effects of russian knapweed (Acroptilon repens (L.) DC) and butter cup (Ranunculus damascenus boiss and gaill), causing problem in winter wheat, on yield and determination of their economical thresholds in van Van ve yöresinde kişlik buǧdayda sorun olan kekre (Acroptilon repens (L.) DC) ve dügün çiçeǧinin (Ranunculus damascenus boiss and gaill) verime etkileri ve ekonomik zarar eşiklerinin saptanmasi üzerinde araştirmalar
