North Island farmers claim chicken manure is helping to spread one of the world's worst cropping weeds, but the Ministry of Primary Industries won't do anything about it.As of last Friday the aggressive weed, velevetleaf, which damages crops by competing with them for nutrients and water, has been found on 248 properties throughout 11 regions of New Zealand. The culprit in the South Island has been identified as fodder beet seed, sourced from Italy and certified by Danish authorities and imported and planted last year.In the north Island MPI says the source is not new, rather the result of an old incursion back in 2011. Farmers in Bay of Plenty and Waikato, disagree. Hew Dalrymple is the Maize Vice Chairman from the Federated Farmers. Colin MacKinnon is the Bay Of Plenty Chairman of the Arable section. Trevor James from AG Research in Hamilton is in charge of the identification of weed seed.