Further problems may develop as the acreage of amaranth increases. Damping-off of young seedlings can be a problem under some conditions, caused by Pythim and Rhizoctonia and stem canker, caused by Phorma or Rhizoctonia. Flea beetles damage young leaf tissue. The adult amaranth weevil feeds on leaves, but the larval stage is more damaging because they bore into the central tissue of roots and occasionally stems, causing rotting and potentially lodging. It is currently unknown whether our insect control measures are cost-effective, but significant loss of yield and quality due to Lygus damage has been observed.
Harvest is the most critical stage in grain amaranth production.
Without careful harvest techniques, it is possible to lose or damage the majority of the seed. If the stems and leaves are too wet, the seeds become sticky and adhere to the inside of the combine as well as the straw discharge. Shattering during the cutting process can also cause losses, so adjustments should be made to minimize shattering of the heads. When reel heads are used it may be helpful to remove several reel bats or raise the height of the reel. Row headers perform better than reel heads for combining amaranth.