Although genetically engineered crop plants carrying traits like disease/herbicide/pest resistance would be very advantageous, they may yet pose a serious threat to the environment due to:
1
excessive use of herbicides to maintain such plants
2
excessive use to synthetic fertilizers to nourish such plants
3
sudden loss of the introduced gene as a result of genotypic competition
4
unpredictability of the consequences of introducing a gene in a new host